ProPhoto RGB | Dan Margulis | Photoshop

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Dan Margulis Applied Color Theory

The Merits of ProPhoto RGB

Posted by: "Andrew Rodney"

Thu Oct 19, 2006 9:29 am (PST)

Re: Moderator notice: stay on topic

---

Dan Margulis wrote:

Also, next month I will be teaching two advanced courses where I am being

joined by people who are roughly as good at color correction as I am. If useful

images surface before then, we can certainly bring them to that group's

attention. For example, Vladimir Yelisseev provided a very useful image on the

question of whether to acquire images into ProPhoto RGB.

Here are two .DNG files you can acquire and see what ProPhoto RGB brings to the party. You are welcome to download one or both from my public iDisk (info below).

I acquired both through Adobe Camera RAW using Camera RAW defaults. Bring one in as ProPhoto RGB 16-bit. Bring one in as Adobe RGB (1998) and for torture sRGB. Do a small saturation move (plus or minus) of say only +7 on each, view the images at 100%. What do you see? Try Channel Mixer and other edits that affect color/tone.

Both images were shot at ISO 100 on a Canon 5D but I have another file from Jeff Schewe from a Mark II that shows the same issues in yellows and greens.

Convert the Adobe RGB (1998) file to LAB and do the saturation move too (interesting but requires a conversion getting us back full circle to doing this in 8-bit or high bit). No need for this move if you stick with the ProPhoto RGB file. Additionally, viewing the image in ColorThink shows it clips in Adobe RGB (1998) and that Adobe RGB (1998) is also too small a color space for output to an Epson running K3 inks (the gamut of the inks in useful areas is larger). Have fun.

Andrew Rodney

My public iDisk:

thedigitaldog

Name (lower case) public

Password (lower case) public

Public folder Password is "public" (note the first letter is capitalized).

To go there via a web browser, use this URL:

http://idisk.mac.com/thedigitaldog-Public

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Posted by: "Iliah Borg"

Mon Oct 23, 2006 7:21 pm (PST)

Re: A case of clear 16 bit superiority -- Follow Up

I understand that anything but ACR is off-topic to this list.

But advocacy of ProPhoto space based on the problems ACR has with other spaces is over my head.

If anybody is interested I can render the file to RGB without any colour space conversions, and then we will see what colour space and bit depth it can be mapped into.

Best regards,

Iliah Borg

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Re: Moderator notice: stay on topic

Posted by: Andre Dumas

Thu Oct 26, 2006 3:55 am (PST)

Hello Andrew,

I downloaded "flower_06 october 18_001" and did the test that you suggested and I found that an RGB1998 16bit version showed some bad posterization while a ProPhoto 16bit version did not show any, I conclude that in this particular test the ProPhoto is clearly superior and that the difference between the two is probably due to the larger gamut of the ProPhoto space (like you said or implied).

I also compared a ProPhoto 16bit and a Prophoto 8bit and there was no posterization in either of them, however, colorwise, the 8bit version ended up better than the 16bit, the tones from dense areas to light areas were much more gradual. In the 16bit, the transitions were more abrupt (occurred within a shorter distance) isn't this a "mild" form of posterization?

I also corrected your RAW in the sRGB 8bit space using my own RAW settings in the Adjust and Curve tabs, using settings that suited the sRGB space best and then, in Photoshop, I did a very simple RGB all-in-one Curve (sorry Dan) instead of the Hue/Saturation move that you suggested so as to achieve an image that appears to have all the qualities of the ProPhoto 16bit image. The sRGB showed no posterization and was a match for the ProPhoto.

This last test supports my contentions that if an image must be handed over to a print shop as an sRGB file (like Wai-hong Chung mentioned) it can very well be done within the sRGB 8bit space all the way, starting with the RAW input right up to the final output file. I also think that, with some difficult images (lots of details in the reds), doing those very important RAW adjustments in the *same space* as the final output space will result in a better final image detail wise.

Andre Dumas

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Re: Moderator notice: stay on topic

Posted by: "Richard Wagner"

Thu Oct 26, 2006 4:11 pm (PST)

On Oct 25, 2006, at 6:03 PM, colorman042000 wrote:

I also compared a ProPhoto 16bit and a Prophoto 8bit and there was no

posterization in either of them, however, colorwise, the 8bit version

ended up better than the 16bit, the tones from dense areas to light

areas were much more gradual. In the 16bit, the transitions were

more abrupt (occurred within a shorter distance) isn't this a "mild"

form of posterization?

Andre,

How are your getting the 8-bit file for this comparison? I can't reproduce what you're seeing, even at 400% mag.

I also corrected your RAW in the sRGB 8bit space using my own RAW

settings in the Adjust and Curve tabs, using settings that suited the

sRGB space best and then, in Photoshop, I did a very simple RGB all-

in-one Curve (sorry Dan) instead of the Hue/Saturation move that you

suggested so as to achieve an image that appears to have all the

qualities of the ProPhoto 16bit image. The sRGB showed no

posterization and was a match for the ProPhoto.

Well, at best it could have all the qualities of ProPhoto except the larger gamut, which the sRGB image would not be expected to be able to match.

I haven't tried this, but I agree that the ACR settings need to be optimized for whichever output space one is planning to use. You can see a large shift in the histograms when the destination profile is changed. ACR uses both RIMM and ROMM in its processing path (ignoring the gamma encoding). After the white balance and initial camera profile application, the data is basically in RIMM space. The tone curve and other user controls transform the image into ROMM space, which is then converted to the final selected RGB working space. An image that is almost identical to the output from ACR in sRGB (at a given set of settings) can be obtained from the ProPhoto image by converting in PS to sRGB, since ProPhoto and ROMM are very similar. The conversion will be with the RelCol intent (since ProPhoto does not have all 3 rendering intents), which is what ACR appears to use internally to convert from ROMM. It might be possible to get a better conversion to sRGB from ProPhoto by first converting back to ROMM, then to sRGB, as the perceptual table in the ROMM profile can be used to "pull in" the out-of-gamut colors.

This last test supports my contentions that if an image must be

handed over to a print shop as an sRGB file (like Wai-hong Chung

mentioned) it can very well be done within the sRGB 8bit space all

the way, starting with the RAW input right up to the final output

file.

I get, at most, a one-level difference in pixels between the 16-bit output from ACR and the 8-bit output, after the former is converted to 8-bit. I suspect that ACR is using 16-bit math until the image is saved, when it would be converted to 8-bit before writing the file.

I also think that, with some difficult images (lots of details

in the reds), doing those very important RAW adjustments in the *same

space* as the final output space will result in a better final image

detail wise.

This has been my experience also, although I have found that converting an image from ProPhoto to ROMM RGB before conversion to sRGB (using the Perceptual rendering intent) seems to work well. It is still not clear to me why Adobe chose to use ProPhoto as an output profile, rather than ROMM RGB. Of course, the "final" profile is seldom sRGB - it will often be a flavor of CMYK or an inkjet printer profile. Tuning images in ACR for sRGB (or AdobeRGB) as well as ProPhoto does not seem to be an efficient workflow, and certainly if one is making fine-art prints or archiving high-res TIFs, the larger gamut of ProPhoto is very desirable. If the only output I was interested in was sRGB, I would tune images in ACR with the output profile set to sRGB.

--Rich Wagner

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Re: Moderator notice: stay on topic

Posted by: "Andrew Rodney"

Thu Oct 26, 2006 7:15 pm (PST)

By all means, run the files through other converters. I still see the issues (but lesser so) when I use Raw Developer on the same .DNGs.

I don(c)ˆt see this as being attributable to just ACR.

Andrew Rodney

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Andrew's Flowers

Posted by: "Ric Cohn"

Thu Oct 26, 2006 10:22 am (PST)

I downloaded the flower dng's from Andrew's site and wanted to share what I see. I took both images and adjusted them in ACR as I normally would and exported them as both AdobeRGB and ProPhotoRGB. Sharpening was turned off for output.

I think I'm finally getting a handle on when this "gamut" stuff might matter to me. Now I'm trying to get a better handle on the best way to deal with it. I recently adjusted a photograph of a woman in a bright Aqua/Cyan workout outfit that I treated in a similar way to how I adjusted this image. For my image I was most interested in maintaining detail in the out of gamut cloths, for Andrew's image I was most interested in maintaining detail in the out of gamut yellows. There are lots of ways to do this, but I think if we're aware of the problem at the Raw stage it makes sense to deal with it as early as possible. It appears to me that a large part of the problem with these images is the poor way that RGB transformations are handled at this point in the technology. It seems crazy that when going from one gamut RGB space to another there's no control over gamut mapping. It all seems so last century.

Another problem is the limitations of our monitors. The same image rendered to different color spaces almost always appears identical on screen because even the smallest gamut spaces are all, or mostly, within our monitor's gamuts. With many printing methods exceeding the monitor in some areas (even CMYK has always had this problem with yellows), I acknowledge it can be important not to lose printable colors. However, when edited, the differences in the channels can make even a bigger difference. I have had images where maintaining detail after necessary corrections requires a lot of extra work.

I am still working under the assumption that I do not want to make ProPhotoRGB my main editing space and that for now AdobeRGB is fine for all or virtually all of my commercial and personal work. Hence I want to handle the gamut mapping into AdobeRGB and then do my image corrections.

I looked at Flower_06October18_001 with an eye toward how I would want to adjust it. When looking at the Blue channel of the AdobeRGB version the first thing I see is total black in the purest yellows. If I convert this file to ProRGB I don't get more detail, I just get a gray blob in the Blue channel. I see 2 choices: 1. Output both ProRGB and AdobeRGB and use the ProRGB Blue channel to blend with. or 2. Output as ProRGB, bring the yellows down to the AdobeRGB gamut and then convert. I think #2 is much simpler.

I took the ProRGB image (16 bit), converted to Lab (no dither), opened a Curves adjustment layer, Command Clicked on some yellow points in the b channel. I then brought down the most extreme yellows to the point where I could just barely see the saturation decrease. I then backed off a little so I couldn't see any difference on my Sony Artisan monitor and converted this to AdobeRGB. Result: a virtually identical looking version with a much better Blue channel. At this point I would normally convert to 8 bit and begin my adjustments.

Any thoughts, comments, criticisms of this working method?

Ric Cohn

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Re: Moderator notice: stay on topic

Posted by: "Andre Dumas

Fri Oct 27, 2006 6:15 am (PST)

Rich your message created a doubt in my mind and I checked back on my tests and realized that the 8bit ProPhoto was Andrew's RAW *but* with modified ACR settings while the 16bit image was Andrew's exact settings. So I'm sorry for this error, my comments are wrong.

I did the test again and could not detect any *obvious* differences between the two images but still the 8bit version appeared to be just slightly darker than the 16bit one, could be an optical illusion, I don't know (?) I compared the two images in ColorThink and there is a difference between them but it seems to be very slight.

My comments about using sRGB as a working space have a lot to do with keeping the workflow as simple as possible when the final output is sRGB and besides I'm not convinced that converting a 16bit Prophoto RGB image to 8bit sRGB at the very end of the process will yield as good an image as one that has been kept in sRGB from beginning to end. Specially if the "process" involves a lot of manipulations.

Your comments about ACR's limitations regarding profiles are very interesting, I'm having a look at Bibble which does not seem to have those limitations.

Thanks,

Andre Dumas

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Re: Moderator notice: stay on topic

Posted by: "Iliah Borg"

Fri Oct 27, 2006 6:20 am (PST)

Dear Andrew,

Thursday, October 26, 2006, 7:26:34 PM, you wrote:

By all means, run the files through other converters.

Here is a rendition of your CRW_0775 with all colour conversions skipped. The "colour" you see is how the camera recorded it.

The file was rendered in the mode we use to profile our converter. Demosaicing is done by binning (substitution of four "incomplete colour" pixels with one RGB; both greens are averaged to form new value)

Only gamma adjustment and normalisation to 16 bit were applied

http://www.pochtar.com/CRW_0775_RM_HDRstraight.zip

-- Best regards,

Iliah Borg ___________________________________________________________________________

Re: Moderator notice: stay on topic

Posted by: "Richard Wagner"

Fri Oct 27, 2006 11:26 am (PST)

Iliah,

Why is the left-hand side of the histogram showing such jaggedness? Aliasing? Something else?

Is binning your standard demosaicing algorithm?

What do you use as an internal color space after profiling - RIMM/ ROMM? Something else?

Where in the process do you usually switch from floating point 16-bit/ 8-bit?

Thanks!

--Rich Wagner

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Re: Moderator notice: stay on topic

Posted by: "Andrew Rodney"

Fri Oct 27, 2006 11:26 am (PST)

This image is from the original challenge not the newer flower image which suggests advantages in ProPhoto RGB and my remarks about using a different converter (I see the same issues with RAW Developer). I(c)ˆm not sure what I(c)ˆm supposed to do with the image you converted scene referred.

Andrew Rodney

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Re: Moderator notice: stay on topic

Posted by: Andre Dumas

Fri Oct 27, 2006 11:27 am (PST)

Hello Rich,

You wrote: "ACR uses both RIMM and ROMM in its processing path (ignoring the gamma encoding). After the white balance and initial camera profile application, the data is basically in RIMM space. "

Rich, you seem to know a lot about ACR's inner chemistry, is there a document somewhere that explains all these internal processes that go on inside ACR? Where can I find it?

Andre Dumas

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Re: Moderator notice: stay on topic

Posted by: "Ric Cohn"

Fri Oct 27, 2006 11:27 am (PST)

Thursday, October 26, 2006, 7:26:34 PM, Andrew wrote:

By all means, run the files through other converters.

I was going to try it through CaptureOne for comparison before I realized that it doesn't support DNG.

Ric Cohn

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Re: Moderator notice: stay on topic

Posted by: "Andrew Rodney"

Fri Oct 27, 2006 11:31 am (PST)

On 10/26/06 9:06 PM, "colorman042000" wrote:

My comments about using sRGB as a working space have a lot to do with

keeping the workflow as simple as possible when the final output is

sRGB...

You mean the final output is an sRGB behaving display? Cause that(c)ˆs the only sRGB output device on the planet.

Your comments about ACR's limitations regarding profiles are very

interesting, I'm having a look at Bibble which does not seem to have

those limitations.

Some find this so called limitation a feature. It greatly reduces the complications in the product. Lightroom is going even further with this use of color management.

Andrew Rodney

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Re: Moderator notice: stay on topic

Posted by: "Richard Wagner"

Fri Oct 27, 2006 1:54 pm (PST)

I wish! I keep an eye out for tidbits and try to reconstruct the bigger pieces from the scraps. Thomas Knoll seems to stay on the cutting edge, so one way to check out what's going on is to follow the imaging literature. There is a book called the Digital Color Imaging Handbook that has several good chapters on color management for digital imaging systems and color image processing for digital cameras, published by the well-respected CRC Press in 2003. Much of the cutting-edge theory is coming out of Kodak, particularly from Giorgianni and Spaulding. If you Google RIMM ROMM RGB you will find several papers by these authors, as well as white papers on RIMM and ROMM and updates by various standards committees. (RIMM and ROMM are now standards - check the Society for Imaging and Science updates. ) ROMM is nearly identical to ProPhoto. RIMM is the "scene-referred" counterpart. The future of digital imaging is in wide-gamut color spaces. Adobe is already there.

As for the quote above, it came from Thomas Knoll himself.

http: //adobe.groupbrowser.com/searchthread137621-RIMM.html

--Rich Wagner

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Re: Moderator notice: stay on topic

Posted by: "Rick Gordon"

Fri Oct 27, 2006 1:56 pm (PST)

Could somebody please change the name of this thread to "Anderw's DNGs" or something? Having this ongoing as "Re: Moderator notice: stay on topic" is the height of irony.

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RICK GORDON

EMERALD VALLEY GRAPHICS AND CONSULTING

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WWW: http://www.shelterpub.com

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Re: Moderator notice: stay on topic

Posted by: "Richard Wagner"

Fri Oct 27, 2006 1:58 pm (PST)

On Oct 26, 2006, at 8:06 PM, colorman042000 wrote:

Rich your message created a doubt in my mind and I checked back on my

tests and realized that the 8bit ProPhoto was Andrew's RAW *but* with

modified ACR settings while the 16bit image was Andrew's exact

settings. So I'm sorry for this error, my comments are wrong.

Andre,

I wish I had a quarter for every time I've done something similar - usually at the beginning of a bunch of work. It happens.

Best,

--Rich Wagner

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Re: Moderator notice: stay on topic

Posted by: "Richard Wagner"

Fri Oct 27, 2006 2:04 pm (PST)

I almost forgot - I3A 7466 also defines an extended dynamic range version of ROMM encoding known as ERIMM RGB. This color encoding has a logarithmic nonlinearity function and a large enough dynamic range to handle the full range of information captured on color negative film, but it requires a minimum bit-depth of 12 bits. (ROMM is defined for 8, 12, and 16-bit encoding.) The times, they are a changin'!

Besides RIMM-ROMM-EROMM, there is also e-sRGB, which is generally similar to sRGB except that it allows for extended encoding of RGB values that range from -0.53 to 1.68. This allows for the encoding of a larger or extended color gamut compared to sRGB. e-sRGB requires 10 bits per component as a minimum encoding bit depth. While both sRGB and e-sRGB are output-referred, sRGB was designed for display-based imaging systems, while e-sRGB was designed for high quality printing.

All of the great new inkjet printers coming out are handicapped without wide-gamut input, so that's where the imaging industry is putting its resources.

--Rich Wagner

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "murraydejager"

Fri Oct 27, 2006 1:59 pm (PST)

Hello Everyone,

Rich, I used your cropped Tiffs to do the test as you suggested. What I found is correct, the ProPhoto file is better!

But why does this effect only seem to happen with Photoshop's Hue/Saturation command? If I do any other adjustments (even radical curves) to any of the files, in any of the three color spaces the same effect doesn't show up. Is this defect limited to this Photoshop command only?

Also, I converted all the files to 8 bits in Photoshop and did the same test. I couldn't tell the difference between any of the 16 bit or 8 bit photos. The same defect to the non-ProPhoto photos existed to the same degree. I don't know why but I was expecting the effect to be worse when doing the saturation adjustment to an sRGB 8 bit file.

Any thoughts would be appreciated,

Murray DeJager

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: Stephen Marsh

Fri Oct 27, 2006 11:08 pm (PST)

Murray, there is a 'secret' option to be used with the Hue/Sat command that not all users are familiar with - which has a profound effect on the effect and thus the useability of the command. Fading to color blend mode or using the command in an adjustment layer set to color (or saturation) blend mode.

Another alternative are AB channel moves to increase saturation.

I have not had time yet to test these files, so I would be interested in your findings if you were simply using hue/saturation in normal blend mode.

Best,

Stephen Marsh.

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Re: Andrew's Flowers

Posted by: Andre Dumas

Fri Oct 27, 2006 1:57 pm (PST)

Hello Ric,

Thanks for an interesting message about Flower_06October18_001, I can see that the AdobeRGB output is inferior to the Prophoto RGB output, and whatever moves one does in ACR will not change that, I tried. Important areas in the blue channel of the AdobeRGB version are out-of-gamut, so details are missing and when you compare the composites, the differences between the two images are obvious.

I tried a different (simpler) recipe: as I came out of ACR into Photoshop with the ProPhoto RGB 16bit image I immediately converted to AdobeRGB 8bit and did a small correction in Levels to match the appearance of the ProPhoto 16bit. The blue channel is as bad as before but when you compare the two composites (16bit ProPhoto - 8bit AdobeRGB) they look identical on the monitor, I assume that the conversion process used the other two channels to compensate for the missing details in the blue channel. In ColorThink the difference between the two can be seen, it is obviously there but is not that great.

By the way many of the dark and denser pixels in both versions are out-of-gamut of my display and of my 8-color printer.

Is it possible to work in AdobeRGB 8bit or even in sRGB 8bit with results that match ProPhoto 16bit?

Andre Dumas

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: murraydejager

Sat Oct 28, 2006 5:18 pm (PST)

Hi Stephen,

I consider myself an 'Advanced Beginner' but I've never heard of this 'secret' option with the Hue/Saturation command. So from now on I'll refer to myself as a beginner!

I had done the tests on the Flower_06October18.001 cropped version files using the normal blending mode.

I redid the tests today using the color blend mode on an adjustment layer and the results were different. The negative effects were greatly reduced but not totally eliminated in the 16 bit sRGB file. I don't think the negative effects were totally eliminated in the 16 bit AdobeRGB file either, but it was close.

But again, this only held true for the Hue/Saturation command. At the, supposed, extreme end I converted the 16 bit sRGB file to 8 bits in Photoshop and then converted to LAB and gave the B channel a saturation boost by bringing in the end points 10 points each. This move closly matched the saturation of the 16 bit Prophoto file after it had received a +7 saturation boost with the Hue/Saturation command on an adjustment layer with a normal blend mode. I then converted back to 8 bit sRGB. Again, I couldn't tell the difference between the 8 bit sRGB file and the 16 bit Prophoto file. No negative effects.

Now, just to make sure, I took the 8 bit sRGB file and converted back into LAB and made another couple of moves in Curves before converting back to 8 bit sRGB. Still no negative effects, until that is, I made a move with Hue/Saturation with a normal blend. Viola! the negative effects appeared!

Now, what I also found interesting is that the negative effects of this last test on the final image, with all the extra moves, was no worse then the negative effects of an otherwise 'pristine' 16 bit sRGB file that took only a +7 move in Hue/Saturation. I would have thought the componding effect all those prior moves would have made the image such a mess that by the time it got to the final Hue/Saturation move it would have collapsed into a random mass of pixels!

So the moral of the storey for me is to stay away from the Hue/Saturation command, with or without any 'secret' options.

Murray DeJager

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "David Marley"

Sat Oct 28, 2006 7:33 pm (PST)

In one of the recent "Professional Photoshop" editions, Dan pointed out the significant improvement when a Saturation adjustment layer's blending is changed to Saturation mode. In normal mode, a saturation increase converts some of the color noise into luminosity noise because, in RGB and CMYK, color and luminosity are inextricably linked.

I tested a 16-bit ProPhoto version of one of Mr. Rodney's excellent flower photos against an 8-bit Adobe RGB version. I added adjustment layers to each with saturation settings of +75 to make the effect obvious--and ugly. When I changed their blending mode to Saturation, the difference was almost completely eliminated. However, neither approach comes close to the quality of increasing saturation in Lab mode as Dan illustrates quite early in "Canyon Conundrum". Also, when I tried a version in Lab mode, I had opened the image as a 16-bit Adobe RGB file and immediately converted to 8-bit before converting to Lab.

David Marley

I don't think I'll ever make a large saturation move outside Lab mode again.

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "Andrew Rodney"

Sat Oct 28, 2006 7:33 pm (PST)

On 10/28/06 4:22 PM, "murraydejager" wrote:

So the moral of the storey for me is to stay away from the

Hue/Saturation command, with or without any 'secret' options.

IF you(c)ˆre referring to my Flower image and the banding with working spaces other than ProPhoto RGB, moral of this story should be, use the appropriate working space for this kind of image (ProPhoto RGB), then there(c)ˆs no issues at all with Hue/Sat and no need for all kinds of extraneous moves into LAB to boast saturation.

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: Stephen Marsh

Sun Oct 29, 2006 3:07 am (PST)

Murray DeJager wrote:

Hi Stephen,

I consider myself an 'Advanced Beginner' but I've never heard of

this 'secret' option with the Hue/Saturation command. So from now on

I'll refer to myself as a beginner!

Hi Murray, well at face value one would presume that adjusting saturation in normal blend mode via the hue/saturation command would only affect saturation! This is obviously not the case. One must change from normal blend to color or saturation blend so that the luminosity component is not adversly affected. This provides a cleaner, more natural saturation increase (but LAB is better).

I had done the tests on the Flower_06October18.001 cropped version

files using the normal blending mode.

I redid the tests today using the color blend mode on an adjustment

layer and the results were different. The negative effects were

greatly reduced but not totally eliminated in the 16 bit sRGB file.

I don't think the negative effects were totally eliminated in the 16

bit AdobeRGB file either, but it was close.

Your moves were much larger than mine, as I had no issues in A98 or sRGB. Saturation was lesser, but detail was better in the sRGB, as expected. There are many ways to combine the higher saturation and the detail if one backs off a little bit on the overall saturation (still keeping high saturation in areas where there is lesser detail).

But again, this only held true for the Hue/Saturation command.

For increasing saturation in normal blend mode this is a poor choice of tool. I prefer LAB, one can even use duped high bit files and blend them back into the original 8bit RGB in color blend mode, perhaps with masks if one is concerned about issues with LAB mode. If not using LAB mode, color/saturation blend mode is a must for the hue/saturation command, in my opinion. There are many options and variations.

Now, what I also found interesting is that the negative effects of

this last test on the final image, with all the extra moves, was no

worse then the negative effects of an otherwise 'pristine' 16 bit

sRGB file that took only a +7 move in Hue/Saturation. I would have

thought the componding effect all those prior moves would have made

the image such a mess that by the time it got to the final

Hue/Saturation move it would have collapsed into a random mass of

pixels!

It is often intersting to observe *theory* and how it holds up when it is *applied* to our various workflows.

So the moral of the storey for me is to stay away from the

Hue/Saturation command, with or without any 'secret' options.

That is one viable approach. For others that do use it, I would suggest that they at least toggle between normal and color/saturation blend modes when using this command to see what effect it has on a given image (results vary).

Sincerely,

Stephen Marsh.

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: Richard Wagner

Sun Oct 29, 2006 3:09 am (PST)

On Oct 28, 2006, at 7:23 PM, David Marley wrote:

Also, when I tried a version in Lab mode, I had opened the

image as a 16-bit Adobe RGB file and immediately converted to 8-bit

before converting to Lab.

I can't for the life of me understand how this could help improve the image - it can only make it worse.

--Rich Wagner

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "David Marley"

Sun Oct 29, 2006 10:41 am (PST)

Richard Wagner wrote:

I can't for the life of me understand how this could help improve the

image - it can only make it worse.

It's not a matter of understanding. It's a matter of looking. I made the LAB version this way, because, for me, editing high-bit, wide-gamma color is a waste of time.

I work for a small commercial printer in Boston. Our clients include universities, museums, architects and small design houses. I spend about 20 hours a week using Photoshop. Most of the pictures with which we work are of poor quality. The improvements that I and my coworkers produce are usually quite large.

Even when adjusting very good photos or art reproductions for architects and museums, Dan's concepts and methods produce a very high level of customer satisfaction. The notion that your theories say something bad is happening holds no import to our clients.

Maybe you could experiment with these techniques and see for yourself.

David Marley

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "murraydejager"

Sun Oct 29, 2006 6:07 pm (PST)

Hi Andrew,

Actually, I agree with your logic. If the problem is caused by a narrow colorspace then the best solution is to widen that space.

If, however, the problem is really the Hue/Saturtion command and by using a wide colorspace like Prophoto RGB one merely covers up the real problem then I don't think justice is being served.

If the Hue/Saturation command is the real problem then I would be very nervous that even the Prophoto file is suffering from some sort of damage, even though it may not be visible on screen. And maybe only after further moves or sharpening may the problem start to rear its ugly head!

The bottom line for me is, what's the real cause of the problem in your flower photos? I'm just having a hard time believing that it's a wide vs. narrow colorspace issue.

Murray DeJager

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "Richard Wagner"

Sun Oct 29, 2006 6:08 pm (PST)

On Oct 29, 2006, at 8:56 AM, David Marley wrote:

It's not a matter of understanding. It's a matter of looking. I made the

LAB version this way, because, for me, editing high-bit, wide-gamma

color is a waste of time.

No one said anything about changing the color space to wide-gamut, and you conveniently avoided answering the question of why converting to 8-bit before conversion to LAB would improve the image. It simply cannot. The rest of your comments are irrelevant to the discussion, but if your output is only directed toward offset printing, and especially if what you usually start with are "poor originals," I would agree that wide-gamut workspaces have no role in your workflow. If you were producing images for fine-art inkjet printing, you would be doing your clients a big disservice by not utilizing the full gamut of the inkjet printers that are currently in widespread use.

--Rich Wagner

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "Andrew Rodney"

Mon Oct 30, 2006 12:54 pm (PST)

On 10/29/06 2:49 PM, "murraydejager" wrote:

Actually, I agree with your logic. If the problem is caused by a

narrow colorspace then the best solution is to widen that space.

Seems pretty clear the issue IS the gamut of the image and working space.

If, however, the problem is really the Hue/Saturtion command and by

using a wide colorspace like Prophoto RGB one merely covers up the

real problem then I don't think justice is being served.

It(c)ˆs not. The image doesn(c)ˆt degrade using the correct working space using those controls. Nor do other images exhibit an issue when they fall within a smaller gamut in context to the working space.

The bottom line for me is, what's the real cause of the problem in

your flower photos? I'm just having a hard time believing that it's

a wide vs. narrow colorspace issue.

Not at all when you plot the gamut of the image within Adobe RGB (1998) versus ProPhoto RGB. Should I provide a 3D Quicktime animation? It(c)ˆs very, very clear that Adobe RGB (1998) hasn(c)ˆt the gamut to hold those yellows while ProPhoto does.

Andrew Rodney

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "Richard Wagner"

Mon Oct 30, 2006 12:58 pm (PST)

Murray,

I don't think that there is a "problem" with the flowers photos. I have *many* images that are comparable. The digital captures have a wide gamut that can easily be shown in ProPhoto. Scans from Velvia into a custom scanner profile are often similar. ACR does a good job of keeping all of the "scene-referred" data and translating it to a wide-gamut "output-referred" color space. If Andrew wanted to produce the best Epson 9800 prints possible, the ProPhoto-based image would be ideal, as there are many colors that can be printed by the Epson 9800 that do not exist in AdobeRGB or sRGB. (Even in the year 2000, a large percentage of the colors that could be printed from an inkjet printer did not exist in sRGB.) The same is true with good scans in scanner space. A lot is lost if the images are converted to sRGB or AdobeRGB - and whether or not this is important depends on the final destination. Trying to compress this information into a small-gamut color space *can* be a problem. The *real* image can only be contained within a wide-gamut color space - be that RIMM, ROMM, ProPhoto, or something else.

I uploaded a gamut plot of the one flower image so that you can see how many colors, out of a 500x500-pixel crop, are out-of-gamut in sRGB. Many of these colors are still out-of-gamut in AdobeRGB, but many can still be printed from an Epson 9800 printer if the colors are maintained in a wide-gamut color space like ProPhoto up until the conversion to the printer space.

http://www.wildnaturephotos.com/Private/AndrewRodney/

I have gamut plots of a Hutcheson Velvia film target (http:// www.hutchcolor.com/hct.htm) that also show the large numbers of **measured** colors that are out-of-gamut for AdobeRGB here:

http://www.wildnaturephotos.com/Public/GamutComparison/

Using a wide-gamut color space for digital masters is not just "my theory" or Andrew Rodney's - it is a recommendation of the American Society of Media Photographers (ASMP) and The Universal Photographic Digital Imaging Guidelines Working Group (http://www.asmp.org/ publications/updig/tools.php#master).

I hope this helps.

--RIch Wagner

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Re: A case of clear 16 bit superiority - Follow up.

Posted by: "murraydejager"

Mon Oct 30, 2006 5:05 pm (PST)

Hi Richard,

I'm glad you responded with the following email. I actually turned on my Epson 2400 printer and printed some flower photos today.

I believe my Epson 2400 and Andrew's Epson 9800 use the same K3 inks so the gamut of both these printers should be comparable. I printed the 16 bit flower photos after giving each a +7 Hue/Saturation move with Normal Blending in Photoshop. Each photo was printed with exactly the same printer settings and on the same paper, etc.

There were No color differences between them!

The only way I could tell the prints apart was from the obvious banding in the sRGB file and the slight banding in the Adobe RGB file. I know that the Histograms showed that the sRGB file was being drastically clipped in the yellow channel and yet in the final print it's undetectable.

Now I'm not suggesting that photos don't exist that have colors that extend beyond the gamut of my monitor, but maybe the histogram isn't the best tool for distinguishing just how far out of gamut those colors really are and whether a more expensive printer with a wider gamut is necessary.

But wait! I saved the best for last. I also took the sRGB flower photo and converted it into LAB and did a mild saturation boost in the B channel as I described in an earlier post. I then converted back into sRGB and printed it the same way I printed the other photos. When comparing all 4 photos together it now appears that I have 3 photos with banding problems and one photo with very smoooth transitions between tones. Yes, now even the Prophoto photo doesn't look that great!

Once again, I'm leaning toward NOT using the Hue/Saturation command for anything important.

Thanks for the uploads and links I will look at them all!

Murray DeJager

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Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: Stephen Marsh

Mon Oct 30, 2006 12:52 pm (PST)

Murray DeJager wrote:

Hi Andrew,

Actually, I agree with your logic. If the problem is caused by a

narrow colorspace then the best solution is to widen that space.

I agree as far as this explanatoin goes Murray, but as you go on to say:

If, however, the problem is really the Hue/Saturtion command and by

using a wide colorspace like Prophoto RGB one merely covers up the

real problem then I don't think justice is being served.

If the Hue/Saturation command is the real problem then I would be

very nervous that even the Prophoto file is suffering from some sort

of damage, even though it may not be visible on screen. And maybe

only after further moves or sharpening may the problem start to rear

its ugly head!

The bottom line for me is, what's the real cause of the problem in

your flower photos? I'm just having a hard time believing that it's

a wide vs. narrow colorspace issue.

There is more going on here than attempting to fill a near full container with more than it can hold. It is more than about moving to a larger container.

The color/saturation blend seems to prove the point for me, when using the hue/saturation command to boost saturation. Normal blend mode is almost next to useless for increasing saturation without hosing the image.

There is no problem when correct technique is used, even in sRGB.

Hue/saturation in normal blend is known to create problems and there are better ways to apply the command, namely color or saturation blend or LAB mode straight line steepening AB channel curve edits that do not move the mid neutral point, or apply image blends.

So for me, in *any* RGB editing space - even ProPhoto, if I was to use a positive value in the H/S saturation slider, it would be done in saturation or color blend and not normal blend mode. After all, this is what one wishes to do, alter saturation independently of hue or tone. Why do the edit in normal blend when it is known to have negative issues? It sort of reminds me of zero threshold sharpening.

I repeated the test in third party software that supports saturation curves and the sRGB 8bpc dupe did not break as it did when using the Photoshop saturation command in normal blend mode. The sRGB does not break when using color/saturation blend mode either.

Sincerely,

Stephen Marsh.

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Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: "murraydejager"

Mon Oct 30, 2006 5:05 pm (PST)

Hi Stephen,

Why do the edit in normal blend when it is known to have

negative issues? It sort of reminds me of zero threshold

sharpening.

Oh my God, what's up with zero threshold sharpening? I just bought, and read, Bruce Fraser's new book: Real World Image Sharpening. I know he doesn't use the Threshold command in any of his teachings.

Shapening is another subject that as a beginner I've been trying to understand thoroughly. I thought it was finally starting to settle in... now this!

I noticed that Dan's next book's chapter on sharpening has been rewritten and I've actually pre-ordered that book so I might have to wait a little while longer before I commit to a final sharpening workflow.

Murray DeJager

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Is sRGB the ideal color space for fine-art inkjet printing in 2006?

Posted by: "Richard Wagner"

Tue Oct 31, 2006 3:50 am (PST)

Murray,

You're right - the histogram is not the best way to determine how far out-of-gamut colors are.

The best way is by actually printing all the colors that a printer is capable of, then measuring those colors and checking to see if a particular color space is capable of encoding those colors. Fortunately, this experiment was done in the year 2000.

The paper I'm referring to was authored by Henry R. Kang and was published in a well-respected, peer-reviewed scientific journal by The Society for Imaging Science and Technology for the 2000 International Conference on Digital Imaging Technologies. The paper is titled, "Computational Accuracy of RGB Encoding Standards." (https://www.imaging.org/store/epub.cfm?abstrid=4231)

The author wanted to look at the output from an inkjet printer and see if the colors that he could print could be represented by different RGB profiles (or RGB encodings). Obviously, if a given color space or RGB encoding is not capable of representing a given color, that color can't be printed, even if the RGB printer is physically capable of doing so.

The technique he used was similar in concept to what I described for looking at the "quantization loss" from converting from RGB profiles to Lab, using a "round-trip" conversion to compare the round-trip image with the original. In Kang's case, he started by printing 150 color patches with an inkjet printer and then measuring the patches to obtain their CIE LAB values under D65 illumination. He then converted these CIELAB values to 13 different different RGB color spaces and back, and looked to see if the colors were the same, and if not, how much error there was. The computational accuracy was judged by calculating deltaE value between the input LAB and the reversed LAB.

Using sRGB encoding, Kang found that an astounding 38 out of the 150 color patches, or 25.3% of all the colors tested, were out-of-range colors. These colors, spread across the spectrum, could not be reversed back to their original LAB values, indicating that the sRGB gamut was too small for a typical inkjet printer. (This was in the year 2000 - inkjet printer gamuts have increased significantly since then.) AdobeRGB showed 15 out-of-range colors (10%), mostly in the yellow, red and purple regions, thanks in large part to the higher chroma of the green primary. sRGB was by far the worst-performing color space out of the 13 tested.

At 8-bit depth, further accuracy could be obtained for "in gamut" colors by increasing the bit-depth. There was practically no visually detectable error beyond 12 bits. Not surprisingly, the out-of-range (or out-of gamut) colors produced the biggest color errors on round- trip conversion, and the errors remained the same for out-of-gamut colors regardless of bit-depth. The lesson from this is that out-of- gamut colors cannot be brought into range by extending the number of bits for encoding sRGB. Increasing the bit-depth increases the accuracy of colors that are "in gamut" by creating finer measurement granularity, but this will not help those colors that are "out-of- gamut."

Out-of-gamut colors can be eliminated, or brought "into gamut" by expanding the RGB gamut with properly selected primaries. RIMM/ROMM RGB and ROM RGB were able to enclose most, if not all real-world producible colors within their gamuts. (ProPhoto is a simplified version of ROMM RGB.) These colors can be printed on inkjet printers.

The only way that the full gamut of current ink-jet printers can be realized is to use a wide-gamut color space. Using sRGB severely limits the color output of inkjet printers. Whether or not you, personally, can visualize the difference is a different question. Many people can. In fact, this is the entire basis for the CIELAB color system. (http://en.wikipedia.org/wiki/CIELAB#CIE_1976_L.2A. 2C_a.2A.2C_b.2A_Color_Space_.28CIELAB.29)

--Rich Wagner

___________________________________________________________________________

Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: Stephen Marsh

Tue Oct 31, 2006 3:55 am (PST)

--- "murraydejager" wrote:

Oh my God, what's up with zero threshold sharpening?

It sharpens everything - even noise.

In Andrew's previous wide gamut test, the image broke after a zero threshold sharpen, but visually same sharpness could be obtained when using different settings with a threshold and then ProPhoto did not show any great advantage and the image did not break (the older shot of the tradesman working and bird feeder image). That test also contained a hue/sat move as well but I can't recall if that compounded the sharpening errors or not (another reason to sharpen the tone and not the colour component of an image).

Zero threshold USM with no edge mask or other limiting and H/S command positive saturation slider moves in normal blend are not workflows that quality conscious users would/should be embracing for real life workflows.

I just bought,

and read, Bruce Fraser's new book: Real World Image Sharpening. I

know he doesn't use the Threshold command in any of his teachings.

And smart sharpen does not have a threshold.

One is pretty much forced to use an edgemask when using a zero threshold, which Bruce advocates (so I am not picking bones with BF here as I too use edgemasks, but not for every image sharpen).

Best,

Stephen Marsh.

___________________________________________________________________________

Re: Is sRGB the ideal color space for fine-art inkjet printing in

Posted by: "murraydejager"

Wed Nov 1, 2006 1:30 pm (PST)

Thanks Richard,

Color... it's a fasinating subject and although its not my intent to become a color scientist, I really just want to take nice photographs, I find the desire to understand is great!

To digress a little bit, it was only a couple of years ago that I purchased a Gretag Color Chart with the idea that if I included it in all my photos I would be able to reproduce the scenes colors 'exactly' as they were! I even once tried to color correct an image so that all the colors of the chart matched the numerical values that I had obtained from some web site on color. I'm learning!

I think its kind of ironic, some people say that ghosts exist, they can see them they just don't have any real scientific data to back them up. Here we have a subject where the scientific data of data loss exists, we just can't often see it!

Murray

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Re: Is sRGB the ideal color space for fine-art inkjet printing in

Posted by: "Richard Wagner"

Wed Nov 1, 2006 10:51 pm (PST)

On Nov 1, 2006, at 4:15 PM, murraydejager wrote:

I think its kind of ironic, some people say that ghosts exist, they can

see them they just don't have any real scientific data to back them up.

Here we have a subject where the scientific data of data loss exists,

we just can't often see it!

Ah, but often you can! Try it, and you'll see.

Best,

--Rich Wagner

___________________________________________________________________________

Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: "murraydejager"

Wed Nov 1, 2006 10:47 pm (PST)

Hi Stephen,

Bruce Fraser does a pretty good job of describing why he doesn't like the Threshold command and what he does instead. So now I understand both of your points.

I'm still very curious to hear what Dan has to say in his new book however, because in his LAB book he talked about the 'Surface Blur' command which Bruce doesn't bring up at all.

Plus Bruce's book doesn't take into account any type of LAB workflow.

Murray DeJager

___________________________________________________________________________

Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: "George Machen"

Thu Nov 2, 2006 7:09 am (PST)

Bruce Fraser does a pretty good job of describing why he doesn't

like the Threshold command and what he does instead.

I haven't read Fraser's recent sharpening book, but I have read some of his old sharpening articles at creativepro.com. I know about edge masks, which often can be used with zero threshold USM, but could someone please summarize the reasons for his objections to non-zero thresholds per se? (Or a link to a Fraser article where he describes his problem with non-zero threshold.) Thanks!

George Machen

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Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: "murraydejager"

Thu Nov 2, 2006 1:46 pm (PST)

Hi George,

I'll quote you what Bruce Fraser has to say from his new book: "The Threshold control is designed to allow you to protect textured areas such as skin tones or slightly noisy skies from being sharpened...

...At higher settings, it has a attendency to create unnatural-looking transitions between the sharpened and unsharpened areas. Because of this tendency, I tend to rely on layer masks..."

Murray DeJager

___________________________________________________________________________

Ghosts

Posted by: "Peter Leyland"

Thu Nov 2, 2006 7:11 am (PST)

Murray - I think its kind of ironic, some people say that ghosts exist, they can see them they just don't have any real scientific data to back them up.

Here we have a subject where the scientific data of data loss exists, we just can't often see it!

Certainly ironic BUT surely in much the same way as the ghost the scientific data that represents a real life image is no more than an arguably poor interpetation of what we actually 'see'. Not so sure about seeing a ghost but seeing red or even double is sometimes on the cards. Obviously, a camera, even a digital one is of little use in these situations - too stupid perhaps?

Peter Leyland

PDQ Print Services

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Re: Is sRGB the ideal color space for fine-art inkjet printing in

Posted by: "williamtheis"

Thu Nov 2, 2006 8:47 am (PST)

Thanks Rich,

I have read much and not fully understood or appreciated these issues. so if I get this, there are at least 3 relevelant colorspaces (with possible excursions to and from LAB) that matter:

1) the scan or digital capture is tagged or assigned it's color space (say sRGB),

2) the monitor we are viewing on has a colorspace (and if callibrated, a color profile) which the image is mapped into for display and our manipulations and

3) the gamut of our printer defines yet another colorspace which will have different extent than either of the two above (for any given color, greater or lesser range)

so let's say we do expand the colors out by going through LAB or ProPhoto which we know is a space LARGER than out printer. On output, photoshop will attempt to condense these colors (with perceptual rendering) into colors that our printer can handle.

But if our color space is SMALLER then my guess from what you have said is that photoshop will not expand it to fit the printer's space?

Is that why you are suggesting the larger-than-the-printer colorspace (like proPhoto or EktaSpace or...) so that you fill or even slightly overfill the range of the printer and then count on Photoshop to map it down to fit?

I'm sorry if this has been covered previously; I have been looking at the archives for a while but am interested in the bottom line, in a way that I think I can understand.

Thanks in advance,

William M. Theis

___________________________________________________________________________

Re: Is sRGB the ideal color space for fine-art inkjet printing in

Posted by: Richard Wagner

Thu Nov 2, 2006 6:00 pm (PST)

William,

Here's the longer response to your question on input profiles (e.g., scanner profiles) as described by Steve Upton, a true color geek who writes well for those who are not color-geeks.

INPUT PROFILES and COLOR SPACE CONVERSION GUIDELINES

http://www.chromix.com/colorsmarts/smartNote.cxsa?snid= 1081

You can find other informative information on his site here:

http://www.chromix.com/colornews/

--Rich Wagner

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Re: Is sRGB the ideal color space for fine-art inkjet printing in

Posted by: Richard Wagner

Thu Nov 2, 2006 6:04 pm (PST)

On Nov 2, 2006, at 10:47 AM, williamtheis wrote:

[snip] So if I get this, there are at least 3 relevelant

colorspaces (with possible excursions to and from LAB) that matter:

1) the scan or digital capture is tagged or assigned it's color

space (say sRGB),

Aieee! Right idea - sort of. You can tag (or more properly, assign) a profile to a scanned image from a transparency, but it is unlikely that sRGB will be the correct profile (unless color management is turned on in the scanner software and sRGB is chosen). Hopefully, someone has profiled the scanner (with color management turned OFF) and created a custom profile for the scanner/film. (With a film like Velvia the gamut of the profile will not be contained by sRGB - it will "poke out" a lot in several directions.) That profile is the one that would be assigned to the scan. For a great reference on scanning, see Don Hutchison's excellent free download, which can be found on this page describing the use of his very-high-quality scanner target: http: //www.hutchcolor.com/HCT_instructions.htm

For a scan, the next step will be converting the image in scanner profile to a "working space" such as sRGB, AdobeRGB, or ProPhotoRGB. This is done in part because *device* profiles are not neutral - e.g., grays will not be equal amounts of R,G, B like 128, 228, 128, and because you need "elbow room" to work in. It will also make it easier when compositing images from multiple sources, etc. This choice of "working space" is critical, as described below.

For digital captures, the "scene-referred" profile is often internal to the RAW processing software, and you chose an output profile. In Adobe Camera RAW, the choices are sRGB, ColorMatch, AdobeRGB, and ProPhotoRGB. (Some RAW processing software, like Phase One's Capture One, will allow you to build and use a custom camera profile.)

Note that, whether starting from a raw scan or a digital capture, the choice of working space (or output profile) is critical. Once the image gets compressed into a smaller space, it cannot be "expanded back" into a larger color space, and the color information that is lost is lost forever (unless you go back to the raw scan or digital file and start over).

2) the monitor we are viewing on has a colorspace (and if

callibrated, a color profile) which the image is mapped into for

display and our manipulations and

Correct. This is the Display Profile that is used by color-managed apps like Photoshop to convert from your working space to the display space, thus color-correcting your image on your monitor.

3) the gamut of our printer defines yet another colorspace which will

have different extent than either of the two above (for any given

color, greater or lesser range)

Correct again. Printer profiles are device profiles - unique for each printer, ink, and paper combination (and many printer driver settings). That's why you have lots of them. Each will have a specific gamut - or range of colors that can be printed. Gamut plots are useful for comparing profiles, to see the advantages and disadvantages of each (or to pick up a bad profile!). You can download a demo version of ColorThink (or ColorThink Pro) to plot profiles in Lab space (or Luv or Yxy) here - it's a great way to visualize the differences between color spaces and profiles. (If you're on a Mac, you can also use the free ColorSync utility to do the same - it's just not as fancy.) These utilities will also allow you to "look inside" of profiles to see how they work. http://www.chromix.com/colorthink/cxctpro/index.cxsa

so let's say we do expand the colors out by going through LAB or

ProPhoto which we know is a space LARGER than out printer.

OK, you can't really "expand the colors out." You can *start* with an image in ProPhoto, or AdobeRGB from a digital capture or scan like we described above.... but if someone gives you an image in sRGB, that's essentially what you're stuck with. Thomas Knoll hasn't written a "gamut expander" function yet. ;-) Picture the colors of an image plotted in Lab. Those colors may fit inside sRGB, AdobeRGB, ProPhoto, or a printer gamut, but you've got what you've got, and it's too late to change it. But let's say that you have a wide-gamut image from a scan or digital capture in ProPhoto...

On output, photoshop will attempt to condense these colors (with

perceptual rendering) into colors that our printer can handle.

We use the word "compress" but the idea is the same. You can also soft-proof this step in Photoshop to see what rendering intent works the best. It might be Perceptual, and it might be RelCol. This step is done through Photoshop's Color Management Module, or CMM. The image's profile is used by the CMM to convert to the Profile Connection Space, then the CMM uses the printer profile to convert from the Profile Connection Space to your printer profile space. (The PCS is usually Lab.) The details aren't important now.

But if our color space is SMALLER then my guess from what you have

said is that photoshop will not expand it to fit the printer's space?

Way correct!!! There are lots of colors that the printer will never print if you always use a color space that is smaller than the printer's gamut. Picture a sphere inside another sphere, both plotted in Lab, where the inner sphere represents your working space gamut and the outer sphere represents your printer gamut. If the colors on the inner sphere "max out" at RGB 255, 255, 255, as do the colors on the outer sphere, you can never give RGB coordinates for the inner sphere that will "reach out" to the outer sphere. You can't address that empty space between the spheres, thus you can't print any of those colors. In the real world, the gamuts are not spherical, and they don't overlap nicely. But to print all the colors that a printer is capable of, the working space must enclose the printer space.

Is that why you are suggesting the larger-than-the-printer colorspace

(like proPhoto or EktaSpace or...) so that you fill or even slightly

overfill the range of the printer and then count on Photoshop to map

it down to fit?

Correct again. Congrats!!!! I think you've got it! That's the big picture. I created a web page describing this a couple of years ago, using AdobeRGB rather than sRGB, but you might find it helpful. It includes a scanner profile for comparison, as well.

http://www.wildnaturephotos.com/Public/GamutComparison/

Hope this was helpful.

Best,

--Rich Wagner

___________________________________________________________________________

Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: "Lee Clawson"

Fri Nov 3, 2006 7:19 am (PST)

Murray,

To me it's a simple warning of the effect of too high a setting. Why this is enough to scare everyone off using it at all (setting it to 0) surprises me.

This isn't unique to Photoshop's USM. Its been around in scanners for a long time. PhotoShop's filter may not be the best implementation of the technique but I'd recommend you do some experiments with the lower settings. Also, you can read what Curvemeister (www.curvemeister.com) has tried to do with their version.

Lee Clawson

2/\V/\7 Studio

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Re: Andrew's Flowers (blend modes & editing spaces)

Posted by: "murraydejager"

Fri Nov 3, 2006 1:35 pm (PST)

Hi Everyone,

In defence of Bruce's techniques he does use the Threshold command in one area of his book, and that's the final Output Sharpening for Inkjet prints.

Also, and most importantly, Bruce makes it clear that these are the techniques he as learned, through much experimentation, to produce the best final results and that others may NOT agree.

Murray DeJager

___________________________________________________________________________

Color space conversion mysteries

Posted by: "klaus_nordby"

Tue Nov 7, 2006 5:14 pm (PST)

I've used Photoshop since v. 1.03 in 1990, studied two of Margulis' books and read heaps of other writings on color theory and pre-press, so I am not a total newbie -- and I'm still having a damnably hard time understanding some odd things concerning color spaces and conversions.

Here is what I do and which mystifies me. I open a DNG or other digital camera raw file in ACR. When I set sRGB as the color space, some parts (usually highlight areas) of some images are flagged in the preview as out-of-gamut. When I change to the ProPhotoRGB space these gamut warnings often disappear -- good! So I convert and open the file in PSCS2, keeping the ProPhotoRGB profile. I then convert the file to sRGB -- and see no change. OK, so I reason that the conversion has gone well. Then I open and convert the same raw file again, this time to sRGB. I take this file -- which had very bad gamut flags in ACR -- and copy it as a layer into the former ProPhotoRGB file, now in sRGB. I set the blend mode to Difference, expecting to see some subtle differences -- but I never see any! Given these conversions, should I not have been able to detect at least some difference -- i.e., that the ProPhotoRGB>sRGB had retained at least a little of what the ProPhotoRGB space seemed to deal with better, in that there were no gamut flags?

Either something funny is going on in this causal chain -- or there are some wrong ideas in my head which makes me not understand what's happening here. Yes, it might very likely be the last! But can any of you here, who undoubtedly understand these things far better than me, please explain what purpose, if any, it serves to open a gamut-flagged raw file into a wider color space -- when it appears that that "extra" information just isn't retained inside PS?

Thanks!

Klaus Nordby

(Oslo, Norway)

___________________________________________________________________________ ‘

Re: Color space conversion mysteries

Posted by: Richard Wagner

Tue Nov 7, 2006 7:15 pm (PST)

Klaus,

You ask some very good questions which I have only recently started to unravel.

Here is what I do and which mystifies me. I open a DNG or other

digital camera raw file in ACR. When I set sRGB as the color space,

some parts (usually highlight areas) of some images are flagged in

the preview as out-of-gamut.

They are.

When I change to the ProPhotoRGB space these gamut warnings often

disappear -- good!

This shows that, in ProPhoto, those colors are in gamut.

So I convert and open the file in PSCS2, keeping the ProPhotoRGB

profile.

Fine. A ProPhoto master.

I then convert the file to sRGB -- and see no change.

When you say, "I see no change" what exactly do you mean? Grossly, visually? This conversion is done with a RelCol rendering intent, so in-gamut (in sRGB) colors will remain the same, and out-of-gamut colors will be clipped to the sRGB gamut boundary.

OK, so I reason that the conversion has gone well.

Maybe. ;-)

Then I open and convert the same raw file again, this time to sRGB.

This will produce *exactly* the same output as taking the ProPhoto image and converting to sRGB in Photoshop, unless you specifically optimize the RAW converter settings to bring everything into gamut before outputting the file from ACR.

I take this file -- which had very bad gamut flags in ACR

-- and copy it as a layer into the former

ProPhotoRGB file, now in sRGB. I set the blend mode to Difference,

expecting to see some subtle differences -- but I never see any!

Correct - they are identical.

Given these conversions, should I not have been able to detect at

least some difference -- i.e., that the ProPhotoRGB>sRGB had retained

at least a little of what the ProPhotoRGB space seemed to deal with

better, in that there were no gamut flags?

Nope. All advantage of ProPhoto is lost in the relative colorimetric conversion to sRGB. It would be different if you converted to a table-based printer profile that could do perceptual rendering into the (bigger than sRGB) printer color space. Even a RelCol conversion from ProPhoto to printer space would likely be better than a conversion first to sRGB, then to printer space, as you would not take advantage of the full gamut of the printer when using this route.

Either something funny is going on in this causal chain -- or there

are some wrong ideas in my head which makes me not understand what's

happening here.

Yea, it took me a while to figure this one out, too.

...please explain what purpose, if any, it serves to open a gamut-

flagged raw file into a wider color space -- when it appears that

that "extra" information just isn't retained inside PS?

First off, PS doesn't "retain" anything. The gamut of your image is determined by the color space that it is in, and how the data got there. You have to follow the data step-by-step, conversion-by- conversion. See above for why a wide-gamut space is better for fine- art inkjet printing (or with some greens and blues, initial conversion to CMYK). The same phenomenon occurs with AdobeRGB --> sRGB conversions.

If your goal is to produce sRGB (or AdobeRGB) masters (say, that's what a client requires), you can make a better master by optimizing the image in Adobe Camera RAW for sRGB (or AdobeRGB).

I refer you to the excellent paper by Spaulding et al on RIMM/ROMM RGB, which is essentially what ACR uses internally. (Camera Raw uses both RIMM and ROMM in its processing path (ignoring the gamma encoding). After the white balance and initial camera profile application, the data is basically in RIMM space. The tone curve and other user controls transform the image into ROMM space, which is then converted to the final selected RGB working space.) http: //www.colour.org/tc8-05/Docs/colorspace/PICS2000_RIMM-ROMM.pdf See in particular the 6th page, bottom left column, paraphrased below.

[Not all the colors that can be encoded within ROMM RGB (ProPhoto) will be within the sRGB color gamut. As a result, it will be necessary to perform some kind of gamut mapping to limit the colors to the appropriate gamut. The simplest form is to just clip all the linear sRGB values... Superior results can be obtained using more sophisticated gamut mapping strategies.]

Conversion of ProPhoto images to sRGB for web use, etc. can be problematic, as described above. Unfortunately, as far as I know, there is not a good gamut-mapping transformation available. ProPhoto and sRGB are both simple matrix-based profiles and use RelCol for conversions. On the other hand, big, table-based printer profiles usually do a great job of gamut-mapping from ProPhoto or AdobeRGB and this makes maximal use of the printer gamut and yields superior prints compared with initially outputting an sRGB image.

It is unfortunate that Adobe Camera Raw cannot do a better job of conversion (in particular, gamut-mapping) from a ProPhoto-optimized image to sRGB. I was also dumbfounded when I discovered that PS- based conversions from ProPhoto to sRGB gave identical results as the ACR conversions (with both being less-than-ideal). It would be nice if ACR gave some control over gamut-mapping to the output profiles. It would also be nice if ACR could save multiple sets of settings, depending on the output profile chosen, so that if you had a set of images optimized for ProPhoto you would not wipe out those settings by re-optimizing the images for sRGB, AdobeRGB, or ColorMatch. Perhaps some of this can/will be addressed in Lightroom.

Hope this helps.

--Rich Wagner

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Re: Color space conversion mysteries

Posted by: "Stephen Marsh"

Wed Nov 8, 2006 12:39 am (PST)

Klaus, in the case of say a wide gamut yellow detail, the yellow is Out of Gamut (OoG) for sRGB or the monitor so when rendering the image into wider gamut space the colour display is simply clipped and they both look the same.

Where you will see the difference is in a softproof/conversion preview to an output device that can contain the bright yellow detail - or even if the output device is smaller gamut one can use perceptual rendering. Over and above this one can then use channel blends and other things to bring out detail lost in the transform, perhaps trading off extreme saturation for some detail while still keeping high saturtion in non detailed areas.

There is a profile that one can use as an intermediate step between matrix based working space profiles. This profile does have perceptual gamut compression, so one can attempt to retain the detail before going into sRGB by going from ProPhoto > PhotoGamut RGB (perceptual) > sRGB (relcol). There will still be clipping going into sRGB, but less.

This is not a magic bullet though, I have mixed feelings about results of using PhotoGamut as an intermediate space due to my experience with different conversion results, but it depends on the image and gamut issues.

http://www.photogamut.org/E_ICC_profile.html

Of course, sRGB is a poor print output space, even for devices that request it. Better results are obtained if one has the true device profile rather than having to use sRGB (as is often the case for Fuji Frontier ouptut).

Regards,

Stephen Marsh.

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Re: Color space conversion mysteries

Posted by: Richard Wagner

Wed Nov 8, 2006 8:48 am (PST)

On Nov 8, 2006, at 1:05 AM, Stephen Marsh wrote:

This is not a magic bullet though, I have mixed feelings about

results of using PhotoGamut as an intermediate space due to my

experience with different conversion results, but it depends on the

image and gamut issues.

I agree - it is not the silver bullet that I had hoped it would be when I first heard about it. In addition to the clipping problem that still remains, there is a significant amount of the sRGB gamut that lies outside of PhotoRGB. Conversion from ProPhoto to PhotoRGB before conversion to sRGB will compress or clip the gamut *more* than is needed in many areas, and a significant part of the sRGB space will never be used. This affects mostly blues/magenta from L* 20 - 70 and reds from L* = 50 - 70 and greens/yellows from L* = 65 - 100. Unfortunately, the shapes of the two gamuts are significantly different from one another. While this trick may work well for some images, I don't think it will work well enough for a standardized workflow.

--Rich Wagner

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Re: Color space conversion mysteries

Posted by: "Stephen Marsh"

Thu Nov 9, 2006 10:03 am (PST)

I agree Richard, I see two main workflow approaches if the final space that the image is being converted to has a perceptual table (presuming that preserving OoG detail is important):

1) Work in a smaller gamut space, convert to final output space and use channel blends/luminosity blends to add lost detail.

2) Edit in a wide/r gamut RGB editing space while using a perceptual softproof. Convert to output space using perceptual intent.

The first approach is more 'traditional' and predates wide gamut editing spaces and ICC profiles and gamut compression. The second approach is the conventional textbook approach offered by most industry players today.

One can build upon this second approach by using Dan's methods, such as channel blends/luminosity blends to enhance the detail.

For example, I might do two CMYK conversions, one from a ProPhoto image using perceptual, the other from an sRGB using Relcol. The Detail from the wide gamut perceptual transform is blended into the more highly saturated sRGB/RelCol transform (normal or luminosity blending or combinations of both). Then one can blend in more detail from wide gamut RGB channels etc. This is just channel blends in CMYK, one can obviously do them up front in RGB prior to conversion. There are many variations on the theme!

Sincerely,

Stephen Marsh.

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Re: Color space conversion mysteries

Posted by: Richard Wagner

Thu Nov 9, 2006 2:12 pm (PST)

Thanks for all of your comments on this, Stephen. You describe several useful tricks that will work well on individual images.

I think the bigger problem is when the smaller destination profile does *not* have a perceptual table, and it is a simple matrix-based TRC profile like AdobeRGB or sRGB. If you want to convert wide-gamut (ProPhoto) images to AdobeRGB or sRGB, OoG detail often becomes obliterated. The best way to deal with this from a RAW image is to re- convert the image from RAW and optimize it for the output destination (AdobeRGB or sRGB), but again, this becomes a huge workflow hassle. (With ACR you can duplicate and save a copy of the sidecar files for ProPhoto then modify the existing sidecar files for the new conversion, or duplicate a set of DNG images to keep the originals.) This obviously won't work if the original was a high-res scan converted from scanner space to a wide-gamut color space. I really don't know of any good options that can be used with a (photographer's) production workflow. ProPhoto -->sRGB often leaves a lot to be desired. I think there's a good market out there for a new tool/utility for making this type of conversion, giving the user control over the gamut-mapping.

Best,

--Rich Wagner

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Re: Color space conversion mysteries

Posted by: "Andrew Rodney"

Thu Nov 9, 2006 7:30 pm (PST)

On 11/9/06 12:39 PM, "Richard Wagner" wrote:

ProPhoto --> sRGB often leaves a lot to be desired.

In what way? I convert to sRGB to go off to the web. The web isn©ˆt color managed but the sRGB files in an ICC application look fine to me. I©ˆm going to Satanic RGB, what©ˆs the big deal about out of gamut colors? We map em all the time. How does the file look?

I©ˆm for better tools but I don©ˆt see the mapping here to be anything to

worry about.

Andrew Rodney

http://www.digitaldog.net/

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Re: Is sRGB the ideal color space for fine-art inkjet printing in

Posted by: "williamtheis"

Thu Nov 9, 2006 11:16 pm (PST)

WOW! I did the following simple experiment. I did a capture into AdobeRGB, converted to LAB and blew the colors out and then into BestRGB (not quite as wide as WideRGB but big nonetheless!). Only a very few colors were out of gamut. I printed it using the printer's profile onto some glossy paper. (Epson 4800, K3 inks, Epson Premium Gloss)

Then I just did a "convert to profile" from BestRGB to AdobeRGB98 and printed it exactly as before with the same printer profile and paper.

WHAT A DIFFERENCE where I had expected none! Hard to put this into words but there was a more "cartoonish" color to the greens, less variation in the reds, etc.

OK. I'm sold.

Bill Theis

___________________________________________________________________________

Re: Color space conversion mysteries

Posted by: Richard Wagner

Fri Nov 10, 2006 3:54 pm (PST)

On Nov 9, 2006, at 4:02 PM, Andrew Rodney wrote:

In what way? I convert to sRGB to go off to the web. The web isn©ˆt color

managed but the sRGB files in an ICC application look fine to me. I©ˆm going

to Satanic RGB, what©ˆs the big deal about out of gamut colors? We map em all

the time. How does the file look?

Although the web isn't color managed, there are attempts to take it that direction. (http://www.w3.org/TR/css3-color/) Just because it's in Satanic RGB doesn't mean it shouldn't look good. ;-)

How does the file look? You're right, most of the time there is not much difference, but at times there is. YMMV...

I©ˆm for better tools but I don©ˆt see the mapping here to be

anything to worry about.

Maybe I'm looking for differences that most would not notice. After all, I have no guarantee that the person on the receiving end has even calibrated/profiled their monitor. ;-)

--Rich Wagner

___________________________________________________________________________

Re: Color space conversion mysteries

Posted by: "Andrew Rodney"

Fri Nov 10, 2006 6:48 pm (PST)

On 11/10/06 12:38 PM, "Richard Wagner" wrote:

Although the web isn't color managed, there are attempts to take it

that direction. (http://www.w3.org/TR/css3-color/) Just because it's

in Satanic RGB doesn't mean it shouldn't look good. ;-)

I don©ˆt disagree. My point is, I make the images look good in ProPhoto RGB. When they go to the web, the convert to sRGB. They basically look the same after conversions. I don©ˆt see a problem here using the current tools.

Maybe I'm looking for differences that most would not notice. After

all, I have no guarantee that the person on the receiving end has

even calibrated/profiled their monitor. ;-)

Then it would be useful to identity what kinds of imagery produces unacceptable results and under what situations. Then if posting to the web, how can be sure that rendering is unacceptable to some or all users (an impossible task I'll suggest).

Andrew Rodney

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RGB Working Space, Part 1 of 2

Posted by: Dan Margulis

Sat Nov 11, 2006 10:33 am (PST)

This list has traditionally taken the position that exotic RGB definitions, those with ultra-wide gamuts or ultra-low gammas, are so unlikely to be used as working spaces by those serious about color correction that extended discussion of them should be considered off-topic.

The broader question of what RGB workspace to use has come up many times on this list and there are several threads have been archived at www.ledet.com/margulis/ACT_postings/ACT.htm. Recently, however, two images have been submitted that again raise the question of whether there can be value to something wider-gamut than most of us use. I have tested them and have uploaded the image files to the Ledet site and analyzed them in the second part of this post. First, it is appropriate to review the basics.

TWO GROUPS, TWO NEEDS

Most list members prepare almost all of their files either for CMYK or for some RGB output where the gamut resembles that of CMYK. Some members, on the other hand, also have to prepare for output devices that have a greater gamut. The two groups have different needs. This half of the posting concentrates on those who do *not* have access to such extended-gamut printers and instead are limited roughly to traditional CMYK.

Narrow-gamut RGBs, by which we almost always mean sRGB although Apple RGB also qualifies, exceed the CMYK gamut in many areas, but in some areas they do not cover all the colors. Moderate-gamut RGBs, like ColorMatch RGB or certain others that have been developed by people who are dissatisfied with sRGB and Adobe RGB, cover almost all of the CMYK gamut, at the price of exceeding it considerably in certain areas. Wide gamut RGBs, of which Adobe RGB is the most prominent example, exceed the CMYK gamut everywhere and exceed it wildly in certain areas. Ultra-wide gamut RGBs like ProPhoto RGB enormously exceed the CMYK gamut everywhere, as does LAB.

For whatever reason, the professional community has split between sRGB and Adobe RGB. Polls at recent Photoshop Worlds suggest that around 95 percent of serious users have chosen one or the other, with the remainder using either moderate-gamut RGBs, sometimes of their own design, or ProPhoto RGB.

Choosing which to use involves several factors, but these posts consider only gamut—the range of colors that each can portray. An RGB gamut that isn't big enough to encompass what the output device can print means that certain colors can never be achieved. A gamut that's too big can result in massive loss of detail when the file is converted into colors that can be printed.

In a perfect world, we would certainly find an RGB gamut that matched the output conditions exactly, neither larger nor smaller. Unfortunately, in our vale of mortal sorrows, all output devices use CMY colorants, which dictate that there is going to be a gross mismatch no matter what RGB we use. The only question is which mismatch does the least damage.

All output devices, presses, inkjet, and otherwise, are relatively poor when producing reds, greens, and blues, because these colors are made up of at least two inks. As inks aren't completely transparent, they can interfere with each other's performance. Solid or nearly solid cyans, magentas, and yellows are the strength areas of all output devices. These are the areas in which narrow- and moderate-gamut RGBs do not cover the entire output gamut.

All output devices also perform relatively poorly as the colors get lighter. This is because they depend on the paper to add lightness, and no paper is perfectly reflective. The worse the paper, the faster the problem occurs. Solid magenta ink on press is outside of the sRGB gamut, but dropping even down to 85% coverage brings it back in. If you're working with extremely white paper, such as many people use on inkjets, possibly a little lower would still stay outside the sRGB gamut.

THE LESSONS OF HISTORY.

As those who follow the history of these conflicts will know, the general pattern is that the group that I sometimes describe as the Conventional Color Management Wisdom lags around five years behind me. Many things *used* to be controversial--whether embedded profiling would ever be a reliable way of passing files to strangers; whether one profiles the proof or the press; whether an inkjet printer can ever be used for a contract proof; whether digital cameras can ever achieve film-like quality; the merits of Photoshop 5; the need for a module to read raw camera data so as to bypass any automated correction; whether a "pushbutton color" situation would ever develop; whether cameras can be profiled for shooting in the field; whether color management cannot succeed without a strong commitment to process control; whether 16-bit color correction creates "a night and day difference, totally obvious to anyone who looks,"; whether conversion to LAB causes "catastrophic damage" to a file; whether printers can be relied upon to convert RGB to CMYK; whether Perceptual or Relative Colorimetric is the right intent for photographic images; whether CMYK images should be tagged; and on and on. In each case, the CCMW argued strenuously against my position before eventually adopting it several years after I did.

In fact, if you go to the ColorSync users list today, and ignore the extremist wing and those who demonize me out of habit, you'll find that it basically occupies the terrain that I have since around 1998, with one notable exception. There is still paranoia about using too small an RGB space.

WHEN THE TARGET IS CMYK OR SIMILAR.

The conventional wisdom has insisted that the RGB definition exceed the gamut of the output device in every respect, forgetting the dangers of *grossly* exceeding it in reds, greens, and blues. People who attend my classes and bring in images that have caused them significant problems. One of the most consistent varieties is detail loss caused by using Adobe RGB on capture when the target is CMYK. One of the most common reader requests for coverage in Professional Photoshop was how to treat RGB and LAB images that contain colors outside of the gamut of the output conditions, and I have page after page of that information in response.

The idea that sRGB could cause problems for CMYK (or photo lab users) is a chimera. As noted above, the only colors that could possibly provoke a problem are heavy, saturated cyans, magentas, and yellows. As a practical matter, the first two don't exist. I have not seen an example in the last five years. Prior to starting work on that section of the book, I asked list members if they had any. Nobody had anything cyan. A couple of people had magenta images (one image of flowers, one of a brilliant silk scarf), and I was already using (in a different context) a picture shot by David Moore of an extremely magenta blouse. All of these were close--but none contained any areas that were out of gamut for sRGB yet printable in CMYK.

As for yellows rich enough to be printable in CMYK, yet out of the sRGB gamut, they exist--yellow peppers, bananas, etc. But we have poor perception of yellows that intense, and such objects tend to be soft, lacking in detail. So it's something to keep in mind, yet not particularly serious.

In the book, I illustrated this with a picture of a yellow pepper whose brightest parts were quite close to 0c0m100y, and therefore out of the sRGB gamut. I printed this CMYK version side-by-side with one that had been converted to sRGB and then reconverted to CMYK. The numbers are considerably different but nobody in the pressroom could tell whether the two images were identical or not.

To show the *potential* problem, I swapped channels and produced one magenta and one cyan pepper. Once again, I converted the CMYK to and from sRGB and printed side-by-side. In both, particularly the cyan pepper, the damage, and the color shift, is clear. I commented that this illustrated the sorts of damage that would be incurred if any pictures actually existed with these kinds of magentas or cyans, but inasmuch as they don't (otherwise, I wouldn't have to manufacture a magenta and a cyan pepper), why saddle yourself with the disadvantages of a large-gamut RGB?

As list members know, I am no fan of either sRGB or Adobe RGB, but if those are the only two choices in the world, most CMYK-oriented users should adopt sRGB. The exceptions would be those who aren't good at color correction or don't have as much time as they would like to devote to correcting the images. These folks would likely get more vivid colors at the expense of detail, a fair tradeoff under the circumstances.

Certainly, there must be photographs somewhere that contain detail in areas that are out of the sRGB gamut but printable in CMYK. At some point in history, some tasteless designer must surely have created a garment in the same color as my magenta or cyan peppers. We should, however, be disinclined to make workflow decisions based on images that show up once every five years or so. If we find a CMYK-bound image for which sRGB isn't big enough, we always have LAB or Adobe RGB.

If would, of course, be senseless to use ProPhoto RGB when the normal output is CMYK. All it would do is add more nonprintable colors--Adobe RGB already covers everything that can be printed, and then some.

WHEN THE TARGET IS BIGGER.

Some of us are fortunate enough to have output conditions that have a greater gamut than that found in CMYK commercial presswork and conventional photo labs. Usually there are extra inks in play beyond the standard CMYK. In the early days it was believed that these extra inks should be vivid colors, like the orange and green of Pantone's Hexachrome system. Such inks have proven too clunky to control easily, and nowadays it's more common to find much subtler secondary inks, often pink and light cyan, sometimes others.

As even more inks are added the point of diminishing returns is reached. There is only so much that one can do with a subtractive process regardless of how many inks are in play, plus, as we all know, there are significant challenges associated with separating an RGB file into four channels, let alone eight or twelve. Unfortunately, it's a powerful sales tool: just as when one camera manufacturer comes up with a 10-megapixel camera somebody else feels they need to introduce a 50-megapixel models and to imply that any photographer who doesn't own one isn't a professional, when one printer manufacturer touts an 8-color printer somebody else comes out with one with 24 inks and says that anything else looks drab.

Vendor claims as to how much these extra inks add aren't completely baseless but they are greatly exaggerated. Most additional gamut comes from the quality of the paper, not the extra inks. Solid colors can be improved marginally; the real gain is in pastels, where light-colored inks can do wonders, provided that the vendor has a decent separation algorithm, which some don't. Particularly, the gamut charts that vendors provide are, in my experience, worthless because they don't represent what their own algorithms can achieve with real photographs.

If you frequently work with such a device, sRGB may be an inconveniently narrow working space, unless you're comfortable with LAB, in which case you could divert brilliantly colored images to that. Some of the heavily magenta images referred to above had sections that were out of the sRGB gamut, but they were also out of the CMYK gamut, so no harm, no foul. With a better inkset and good paper, if you shoot a lot of pink flowers and the like, that safety net may disappear.

Therefore, I think that ColorMatch RGB, or even something as wide as Adobe RGB, is appropriate for people who commonly have to worry about such output. Regrettably, in the last few years there has been advocacy of ultra-wide RGBs as working spaces. Such clumsy editing spaces create many handling problems. These have been discussed frequently on this list and there is no point in rehashing them. The question is whether there are ever any advantages that might compensate for having to put up with them.

This refers to editing only, not temporary storage. I frequently acquire images from Camera Raw into ProPhoto RGB, which is its resident ultra-wide space, because the resulting file is often the best for channel blending purposes, even if I'm headed for CMYK. But I make a copy of it and convert to a more rational RGB as the base file, and use the ProPhoto version only for blending.

We are speaking of photographs here. If you have some other plan, like creation of artificial images with colors far more intense than found in the original photograph, then all bets are off. Limiting it to photographs, I have said for a number of years that I have never seen a single one for which Adobe RGB is insufficient, regardless of output condition. In the second half of this post, we will look at two images that challenge this.

Dan Margulis

___________________________________________________________________________

RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Sat Nov 11, 2006 10:35 am (PST)

This continues the discussion of the preceding post, which ended by questioning whether a natural photograph exists containing detailing in colors that can be printed on any existing output device, yet are beyond the gamut of Adobe RGB.

If one were ever to be found, it would, I wrote, almost have to be something yellow. No matter how many inks are in use, output devices still have trouble with reds, greens, and blues. There theoretically can be a problem in certain magentas and cyans, but few if any photographs exist that contain these colors. Only in yellows, which are much more common, is there a respectable chance that the original capture might contain something that can be printed yet Adobe RGB can't accommodate. But it would have to be not only a brilliantly yellow object, but one with heavy detail. We don't have good perception in yellows that intense.

We now turn to two images that are intended to suggest that an ultra-wide RGB is useful. Surprise! They're both strongly detailed yellow flowers. One is from Vladimir Yelisseev, the other from Andrew Rodney. I have extracted and posted several sub-images from each and posted them at http://www.ledet.com/margulis/2006HTM/RGB_Workspace_Images.zip

(BEWARE: It's a 60 mb file!) All variants are based on files opened with Camera Raw defaults into either sRGB, Adobe RGB, or ProPhotoRGB. Andrew has posted his raw images on his site. For space reasons Vladimir's raw image is not here, but it is on the CD of the new book [PP5E].

These files are large enough that anyone inclined to test them on printers should be able to do so. They are not JPEGged, in the interest of preventing artifacting.

DESCRIPTION AND WARNING.

Vladimir's image is of a flower with brick-reddish outer petals but an intensely yellow center, from which filaments emerge. Andrew's shows a yellow, but much paler, flower, also with prominent filaments. It is one of two substantially similar images that he posted in .DNG format. Because he was apparently unaware that .DNG files may derive from various sources, I requested that he repost the files in raw format. He did not post the same images, but two others that made it clear that the original .DNGs had not been altered before being saved. I chose this one as offering the fairest comparison to Vladimir's.

We have heard on this list how there is never any harm in acquiring images in ProPhoto RGB. The first set of examples demonstrates how wrong that idea is. In setting up this demonstration, when there's a question of which version is superior, the images are only identified by letter and are placed randomly. In this way, you are invited to decide which is better without being prejudiced by knowing in advance which is which. The identifications--if you need them--are kept in a separate text file, which is posted in the Files section of this group at http: //tech.groups.yahoo.com/group/colortheory/files

Nobody advocates working in sRGB if you have an extended-gamut printer; the only question is whether you should use something bigger (meaning, to most people, Adobe RGB) or whether an ultra-wide RGB is needed. It is, however, useful to *test* sRGB vs. ProPhoto, because any problems Adobe RGB might have would be worse in the sRGB version. If we conclude that sRGB is not sufficient, *then* we can look at whether Adobe RGB is good enough.

We'll start, oddly enough, in CMYK. Images A and B are Vladimir's flower, C and D Andrew's. In each case, one version was opened in ProPhoto and converted into CMYK using SWOP v2; the other opened in sRGB and treated similarly. It has been asserted that the two pairs should be identical. As you can see, they aren't. The images opened in sRGB are superior, particularly in Vladimir's shot. In Andrew's, you have to paste one image on top of the other and toggle back to see the difference, which is subtle (the ProPhoto version goes green in the shadows). Again, I'm not identifying which is which--you can get that information from the text file. If you agree that the sRGB-to-CMYK versions are better, this also suggests that printing the sRGB files to any printer without an extended gamut would also give better results.

What you see as composite on the monitor in these CMYK images is reasonably accurate. All remaining examples, however, are ProPhoto RGB files. Most are beyond the capability of your monitor to display accurately, so you need to look at the red and green channels to get an idea of what detail is lost. (We are insensitive to contrast variation in the blue channel, so that can be ignored.)

THE TEST RESULTS.

To know whether there is any point to using a wider gamut space requires looking at several factors. We need to know whether colors are actually present that the smaller RGB does not contain; whether any such colors can actually be printed by any known device; whether we would even wish to print those colors if possible, and whether the area contains significant detail. In the current images, the results are as follows:

1. Do any colors exist in the ProPhoto versions that cannot be replicated in the sRGB versions? Yes. Versions E and F show these areas, exaggerated to the same extent. Vladimir's image has a considerably larger area that encompasses almost the entire center of the flower and implicates the red channel even more than the blue. Andrew's is limited to the blue channel.

2. Are these colors achievable on any current printer? In Vladimir's case, probably, in Andrew's, unlikely. Versions G and H show how the CMYK versions vary from the ProPhoto originals. If we were to assume an extended-gamut printer, the shapes of the areas would be about the same, but they would be somewhat smaller.

Compare Versions E and G, and F and H. In Vladimir's case, there is only a fair correspondence between the two. Not all the areas shown as being out of the sRGB gamut are out of the CMYK gamut--and that's even assuming we are talking about offset presswork. If we assume something better, obviously this problem gets worse.

Andrew's image does not have this issue. The entire area that's out of gamut in sRGB is also OOG in CMYK, and quite a bit more. Even if it's area is significantly reduced there will be no problem.

This finding was confirmed by Murray DeJager, who tested it using the same inks and printer advocated by Andrew and Rich, and found no color difference between files output in sRGB and ProPhoto.

3. Do we really wish to achieve these colors? In Vladimir's case, some of them; in Andrew's, definitely not. Cameras don't see flowers the way we do. We break the colors apart (simultaneous contrast) and we dislike reproductions that overwhelm us with similar colors. Neither of these images is acceptable as shot for that reason--the both blast us with too much yellow.

In Vladimir's case, we want to tone down some of the center so that the brightest yellows seem more intense by comparison. I will talk about how to do that in a bit. The very yellowest parts, however, need to be as yellow as possible. So, if extra gamut is available, we want to make use of it.

In Andrew's case the flat yellow area is not an important part of the flower. It distracts from the pale yellow petals, which no printer has much of a chance of matching, but which need to be as yellow as we can make them.

4. Does the area contain significant detail? This is another way of asking whether opening in the narrower-gamut RGB can damage the file. Vladimir's image, yes; Andrew's, no.

When Andrew presented his image he suggested that running the Saturation slider of Hue/Saturation or Channel Mixer on the sRGB version of his file would show that it was inferior. These suggestions were so quickly debunked by other members of the list that little time need be spent on them. Channel Mixer is inappropriate for comparing *any* two RGBs because of the variance in channel structure. Running the Saturation slider on an areas that is already near the edge of a colorspace's gamut is something that most beginners would know not to do. Also, it is well known that increasing saturation works significantly better in LAB than any RGB, as verified by Murray's testing, where he reported that a saturation increase in LAB with Andrew's picture resulted in output clearly superior to either the sRGB or ProPhoto version.

If we wish to know whether opening a file in sRGB has damaged it in a way that ProPhoto would not, there is only one valid way of finding out, which versions J and K (Vladimir's) and L and M (Andrew's) allow you to test for yourself. In each pair, one of the unidentified variants was opened directly into ProPhoto. The other was opened into sRGB, but then converted in ProPhoto. You now need to ask whether there is anything you could possibly do to one variant that you couldn't duplicate in the other. In Andrew's case, the answer is no. For most purposes, the version acquired in sRGB and converted to ProPhoto is actually superior because the affected area has been desaturated slightly, which is desirable. There is no loss of detail except in the blue channel, which has no impact on overall contrast.

I conclude, then, that Andrew's image handles at least as well, and probably better, if acquired in sRGB as opposed to ProPhoto. There is therefore no point in testing it further. In Vladimir's, however, I conclude the opposite. All three channels are damaged in the sRGB version, especially the red. This could be repaired with some effort but obviously the scenario is not desirable. I therefore regard it as proven that at least one real-world image exists for which opening in sRGB causes problems if the destination is an extended gamut printer.

The next step, then, is to find out if the problem persists if Vladimir's image is opened in Adobe RGB rather than sRGB. Version N corresponds to the earlier Version E: it shows the area in which AdobeRGB version falls short of the one acquired in ProPhoto. Of course, the affected area is much smaller than the sRGB version, but it's still there, and it's still conceivable that the colors are printable, and we would still wish to achieve some of them if they are.

So the question boils down to what would happen next. I think that anybody who knows anything about color would attempt to add shape to the yellow area because as it stands there would just be a yellow blob in the center of the flower. The likely way to do this would be to lightly stamp the green channel into the luminosity of this area, while assuring that the very brightest parts become as yellow as possible. There are several ways to achieve this effect. If you would like to experiment with one, I provide version O, a two-layered blank document with the top layer at reduced opacity and with Blend If options enabled to restrict the move largely to the yellow areas.

In testing this, I used a ProPhoto file plus a ProPhoto to Adobe RGB back to ProPhoto file. The results were equivalent because the green channels of the two were basically identical. The approach would be to convert a copy of the image to LAB, increase saturation in the yellows to taste, and put copies on both layers of version O. Then, on the top layer, replace the L channel with the green channel of either of the RGB versions. Where to set opacity and Blend If is a matter of taste, I like the settings in Version O, but you should get the same results with whatever you like.

The last two paragraphs, however, are relevant to nothing, because a sensible person would not open that image into Adobe RGB. The moment I saw the preview of Vladimir's image in the dialog I knew that it might be that exceptional image for which Adobe RGB might not be sufficient. I did not know, as I do now, that I could get just as good a result from opening it in Adobe RGB. So, had it been a real job, I would not have wasted time finding out. I would simply have opened the file in ProPhoto RGB and gotten out of it when convenient.

CONCLUSION.

Ultra-wide colorspaces serve an important role in conversions and file interchange. It's not dangerous to store a file in such a space if you are careful with what happens to it thereafter; Photoshop, for example, uses ProPhoto RGB as a reference space in Camera Raw. As editing spaces, they have grave disadvantages. This is as true for LAB as it is for ultra-wide RGBs. LAB, however, has many important advantages that make it suitable for many kinds of images. Ultra-wide RGBs have none. The argument, heavily subsidized by vendors whose profit depends on ink sales more than printers, is that the printers are so incredibly capable that only an ultra-wide RGB can feed them. If that were true, it might or might not be a justification for accepting all the disadvantages.

As these files show, however, it isn't true. Charts showing that certain printable colors are out of an RGB's gamut are meaningless if no pictures exist that attempt to access those colors. As I have previously pointed out, just about the only photograph that could require the use of an ultra-wide RGB and still potentially be printable would involve brilliant yellows containing critical detail. Vladimir's image meets that description, but it's a rare case. If you get a raw file of a brilliant yellow flower that has significant detail, you recognize it for what it is, and use ProPhoto to acquire it.

Meanwhile, you need to consider that the image being offered by the proponents of ultra-wide spaces is the best they can do--but it doesn't even need Adobe RGB, let alone something wider. Andrew's image works perfectly well in sRGB, possibly better than ProPhoto RGB.

If you are planning to force a file into the deep magentas and cyans that don't exist in photographs but are achievable on certain printers, you will get better quality from LAB, but an ultra-wide RGB may serve. However, those who think that they are getting something out of editing normal photographs in an ultra-wide RGB are only fooling themselves. If they are lucky, their quality won't be hurt too badly. If not, they'll wind up with clunky corrections and lots of problems with out of gamut colors. This is not a workflow for those serious about image quality, so I reiterate the traditional policy of this list that extended discussion of editing in exotic RGBs belongs elsewhere.

Dan Margulis

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Re: RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Tue Nov 14, 2006 11:05 am (PST)

On Nov 11, 2006, at 7:05 AM, dmargulisnj wrote:

Nobody advocates working in sRGB if you have an extended-gamut

printer; the only question is whether you should use something

bigger (meaning, to most people, Adobe RGB) or whether an ultra-

wide RGB is needed.

Well, that's good to hear. Essentially every inkjet printer made today is an "extended-gamut printer" with a gamut that will not be contained by sRGB or often AdobeRGB.

To know whether there is any point to using a wider gamut space

requires looking at several factors. We need to know whether colors are actually

present that the smaller RGB does not contain; whether any such

colors can actually be printed by any known device;

These questions were settled long ago nearly everywhere in the world outside of this List. You must have missed (or didn't understand) my earlier post on this topic (http: //tech.groups.yahoo.com/group/ colortheory/message/15447) and the work by the many Standards groups on expanded gamut color spaces (e.g. http: //www.imaging.org/pubs/ reporter/standards/standards16_5.pdf and http: //www.color.org/ IST_182_Color_Stds_Activity.pdf). You must have also missed Bill Theis's post, where he personally discovered the wider gamut of his printer by doing his own experiment (http://tech.groups.yahoo.com/ group/colortheory/message/15479). The issues you raise were answered - scientifically - in the year 2000 (https://www.imaging.org/store/ epub.cfm?abstrid=4231). Henry Kang showed that there are a *lot* of colors that can be printed on inkjet printers that don't exist in sRGB, and therefore can never be printed from an sRGB source document. The fact that this is still in dispute on this List baffles me. In the study by Kang, sRGB was the *worst-performing* colorspace of the 13 that he tested, to the point that some of the tests with sRGB could not even be completed. (ROMM-RGB, a.k.a. ProPhoto, did quite well.) sRGB was designed as a monitor profile - it was not designed to be used as a working space for print, and it often does quite poorly when it is forced into that role. The small gamut of sRGB relative to even consumer-level inkjet printers was the reason Epson, Canon, Eastman Kodak, Fuji and Matsushita developed the *expanded-gamut* YCC-based DPOF - Print-Image-Matching system (PIM) for consumer digital cameras and printers (http:// www.printimagematching.com/pdf/what_is_pim/pim_wp.pdf) which was then rolled into Exif 2.2. sRGB simply doesn't cut it, even for consumer- grade inkjet printers.

It is quite easy to prove that inkjet printers can print colors outside of sRBG or even AdobeRGB. It is done every time someone profiles an inkjet printer, especially for glossy/luster paper. Simply look at the measured values of the test chart and plot them in Lab. Many will be outside of sRGB and AdobeRGB - just like the gamut plot shows. You don't even have to make the measurements yourself - just open up a printer profile that has stored measurement data and you can see/plot the measured values - many are clearly outside of sRGB/aRGB. Obviously, the printer can print these colors, because that's where the measurement data come from, and people can see these colors, because they're in CIELAB. Why there is such resistance to accepting this is beyond me.

Of course, the best way to "prove" that wide-gamut images are better for inkjet printing is to simply print a wide-gamut image, then compare it to the same image that has been converted (dumbed down) to sRGB. The wide-gamut print will easily win in side-by-side comparisons. Real-world practice confirms the scientific study results. Camera-Printer manufacturers discovered this and developed a consumer-level alternative to sRGB. Bill Theis did the experiment himself, and easily convinced himself that the "theory" was both accurate and relevant. Anyone who disputes this should do the same, so that those on this List attempting to make quality inkjet prints - either professionally or for family-friends, can get the most out of their images/printers. It's time to end the myth that sRGB is a "good enough" color space for print. Quite simply, it is not.

--Rich Wagner

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Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "Iliah Borg"

Tue Nov 14, 2006 12:40 pm (PST)

Dear Richard,

Take a reverse approach. Print a reasonably wide target on a well-profiled printer, shoot it and see what colours are reproduced by the camera and how they are reproduced. But do not use invented colours coming from ACR or other raw processors. Look into raw data itself.

Best regards,

Iliah Borg

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Tue Nov 14, 2006 11:34 pm (PST)

Iliah,

The question of whether or not there are colors that can be printed that do not exist in sRGB has nothing to do with ACR or cameras or RAW data. You are confusing two completely different issues. A significant portion of common inkjet printer gamuts cannot be printed using image colors that are in sRGB. Those colors *do* exist, just not in sRGB. Many of these out-of-sRGB-gamut yet printable colors can be easily obtained by methods other than digital cameras - e.g. scanning film. Scans of transparencies shot on Velvia, for example, are often very much out-of-gamut in sRGB and AdobeRGB, yet many of these OoG colors are printable. Of course, digital cameras can capture these colors, too, and the marketplace is far more concerned with digital capture than with scanned images.

Your example using output-referred image data as a source will not demonstrate what the scene-referred image capture data of the camera will look like - you are essentially treating the camera as a color copier, which it is not. Viewing conditions are not comparable, the dynamic range is not comparable, etc. A colorimetrically accurate digital capture of a scene will not represent a pleasing image of a scene. The encoding states are different, and a transform is needed to go between scene-referred data and output-referred data.

Please see the ICC white paper:

http://www.color.org/ ICC_white_paper_17_ICC_profiles_with_camera_images.pdf

and http: //www.colour.org/tc8-05/Docs/colorspace/PICS2000_RIMM-ROMM.pdf

There is a lot of effort being made to develop imaging systems that will handle the the larger "gamut" and dynamic range of typical consumer digital capture images without resorting to RAW data storage. Why? Because these additional colors *can* be printed, and "soccer moms" want great prints without using a RAW processor. Besides the earlier references that I cited (especially the pdf on Print Image Matching which describes the use of the sYCC color space), you should look at:

Technical Overview: Using a Residual Image to Extend the Color Gamut and Dynamic Range of an sRGB Image

http: //wwwpl.kodak.com/global/plugins/acrobat/en/professional/ products/cameras/erit/whitePaper_ecgadr.pdf

The goal of the authors was to make a file that "looks like" a plain sRGB image for monitor use, yet has additional gamut information stuffed inside that can be used for printing. (It is OoG for display.) By some neat tricks using metadata, they can re-create the RIMM image from an image stored as sRGB, which can then be used for wider-gamut output.

If you look at the references I cited, you will see that the trend/ direction of the industry (and international standards committees) is toward wide-gamut capture/encoding/output. sRGB is simply inadequate for today's output devices. If you don't accept this, you will get left behind.

Best,

--Rich Wagner

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "John Denniston"

Wed Nov 15, 2006 11:18 am (PST)

At 07:51 PM 11/14/2006 -0700, Richard wrote:

The goal of the authors was to make a file that "looks like" a plain

sRGB image for monitor use, yet has additional gamut information

stuffed inside that can be used for printing.

Hi Richard,

Will these images on an uncalibrated sRGB monitor match the prints?

Regards,

John Denniston

www.dennistonphoto.com

www.dirtbikephoto.com

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Wed Nov 15, 2006 1:47 pm (PST)

I doubt that anything on an uncalibrated monitor will match prints - except by sheer luck.

Kodak has used this "Extended Range Imaging" technology with pro- level cameras. "This proprietary technology offers an innovative image file format similar to a JPEG, but with the dynamic range and color gamut information of raw DCR camera files." It uses a Photoshop plugin to read/write the file format and extract the additional image data. If you look at the gamut of the Kodak pro cameras (e.g., 560_660_strobe_std_product.pf), it greatly exceeds sRGB in essentially all directions, and aRGB except for greens. Pulling this off was quite a feat.

http: //www.kodak.com/global/en/professional/products/cameras/erit/erit.jhtml

--Rich Wagner

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Wed Nov 15, 2006 3:44 pm (PST)

Rich Wagner writes,

You must have missed (or didn't understand) my

earlier post on this topic

(http://tech.groups.yahoo.com/group/ colortheory/message/15447)

I missed the part of it that referenced a photograph. The point of the post seemed to have been that we should be using ProPhoto RGB as a workspace. So I was looking for an example of a real photograph that would benefit by such handling. Instead, all that I could find was a link to some charts. I don't sell charts, or print charts. My clients do not care about charts.

Andrew Rodney posted a photograph that he claimed would benefit from use of ProPhoto, but as it turned out sRGB, let alone Adobe RGB, would have been more than sufficient.

Your charts and your rhetoric seem to suggest that there are powerful incentives for working in ProPhoto. If so, it would seem to be a simple matter to produce a photograph that handles better when acquired in ProPhoto than elsewhere. Until you can do so--and Andrew certainly can't--charts are worthless.

and the work by the many Standards groups

on expanded gamut color spaces (e.g. http: //www.imaging.org/pubs/

reporter/standards/standards16_5.pdf

That document doesn't seem to reference any photographs either. It has a bunch of mathematical tables. Tables don't pay the bills. Tables are not judged on their aesthetic virtues. Tables cannot be opened in Photoshop. Clients care very little for tables. If photographs cannot be produced where ProPhoto is beneficial, tables are of no value.

You must have also missed Bill Theis's post, where he personally discovered the wider gamut of his printer by doing his own experiment (http://tech.groups.yahoo.com/

group/colortheory/message/15479).

No, I saw that one. It began, "WOW! I did the following simple experiment. I did a capture into

AdobeRGB, converted to LAB and blew the colors out and then..." This rendered the rest of the message irrelevant. In real life, we do not deliberately blow out colors. Demonstrations that require sabotage of images prove nothing.

The issues you raise were answered

- scientifically - in the year 2000 (https: //www.imaging.org/store/

epub.cfm?abstrid=4231). Henry Kang showed that there are a *lot* of

colors that can be printed on inkjet printers that don't exist in

sRGB, and therefore can never be printed from an sRGB source

document.

Good, but did he answer--scientifically--whether any natural photographs exist that access these colors? Did he reference any photographs that do?

It's time to end the myth that sRGB is a "good enough" color space for print.

It sounds like you're just the man to do it, Rich. It seems that you are or have been a photographer. You must have quite a storehouse of photographs. If any of them show why sRGB is not good enough for print (I am assuming you are referring to conventional CMYK) or why Adobe RGB is not good enough for an inkjet, then by all means let's have a look at them.

If not, please recall that this is the APPLIED color theory list. Theories that cannot be backed up with real photographs have no application. The post that you responded to was an analysis of two real images. If your claims can't be backed up with photographs, please take them to some list that is more interested in rhetoric than results.

Speaking of which, you also had a theory that converting a photograph to LAB and back resulted in 24-level differences. Did you ever find a photograph to back up that claim?

Dan Margulis

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "john castronovo"

Wed Nov 15, 2006 7:59 pm (PST)

With all due respect Dan, many of us don't only print "real photographs".

Just today I was scanning some artwork for the purpose of inkjet reproductions. The original designs were created with Prisma colored pencils and some of them are quite saturated. It's my job to retain as much of the original color gamut as possible. My Betterlight scanner is producing color that's way beyond what Adobe98 will hold and if I have any chance of printing those colors accurately I feel that I have to use a working color space large enough to contain them without clipping. I often find that artists use colors that are beyond what I can view on a monitor or even print and they really don't care about what is in gamut for a real photograph. How much of the Pantone book can be reproduced in sRGB or aRGB? Can I tell an artist not to use those colors?

Even photographers who shoot films like Velvia want scans that capture more than "normal" reality and they don't want me telling them that they have to settle for the way I think their work should look because I know the colors of the real world better than they do in their mind's eye. Instead, some want me to saturate their work beyond what's in the film if I can.

I fully understand where you are coming from in that the typical file will be quite comfortable in sRGB and be safe for everyone's use in that space. We hand off files in sRGB all the time. But for many of us who are using printers that can do more, I think there are good reasons to have to go beyond that.

Maybe I'm kidding myself though, so please tell me, is it your contention that none of today's output (think about Lambda and Lightjet Duratrans, film output, wide gamut dye inks on polyester media, varnished canvas, etc. and not only Epson inks) is capable of taking advantage of color gamuts larger than aRGB, or just that it doesn't matter if they can because no "important" colors are in those spaces?

john castronovo

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Wed Nov 15, 2006 8:00 pm (PST)

On Nov 15, 2006, at 4:26 PM, Dan Margulis wrote:

That document doesn't seem to reference any photographs either. It

has a bunch of mathematical tables. Tables don't pay the bills.

Tables are not judged on their aesthetic virtues. Tables cannot be

opened in Photoshop. Clients care very little for tables. If

photographs cannot be produced where ProPhoto is beneficial, tables

are of no value.

Actually, that reference is a standards update from 2001, and it has one table, called "Comparison of RGB Definitions." I don't think any of the ICC definitions/standards have photos in them, nor the ANSI standards, nor the ISO standards, nor the I3A standards, and so on. Yet these standards have allowed interoperability and compatibility between computer platforms, cameras, printers, scanners, etc. Without them, there would be no JPEG files, or TIFF files, or color correction as we know it. Anyone doing image correction would need to have their own closed-loop system. Rendering intents and gamut mapping wouldn't exist. Monitor calibration wouldn't exist. The 20- page AdobeRGB (1998) spec has not one photo in it, yet it allows us to use it as a common language for predictably combining images and re-purposing them. Color theory is by its nature mostly mathematical.

If I tell you that an inkjet printer has no yellow ink, you don't need to print a photograph to see that you can't print an orange sunset. Likewise, if a color space like sRGB can't send the correct numerical values to an inkjet printer to print particular colors, you don't need a photograph to prove it. If the LAB colors that a printer can print in a test chart aren't within the sRGB color space, no photograph in sRGB will *ever* print those colors on that printer - there's no sense in even trying. If, on the other hand, those colors *do* exist in a different color space - regardless of what the color space is called - those colors *will* be printed in a photograph containing those colors. By definition, if you can't print all of the colors of a device, you have limited the gamut of that device. That's what's happening with current inkjet printers and sRGB. That's also why gamut maps are so helpful to those who understand them.

ProPhoto is not the answer to all color management problems, but sRGB is increasingly being recognized as a limiting factor in high-quality inkjet printing and photofinishing. Papers are better, inks are better, the printing technology is better... to the point that now the gamut of inkjet printers is being limited by an image encoding format that was initially designed for CRT viewing on the Internet. Even the gamut of LCD monitors like the Eizo CG221 have exceeded sRGB and matched AdobeRGB. Why should it be a surprise that printer gamuts have exceeded sRGB?

My comments were in response to your statement that,

"We need to know whether colors are actually

present that the smaller RGB does not contain; whether any such

colors can actually be printed by any known device;

As I pointed out, the answers to these questions have been known for a long time, and the answers are a resounding Yes and Yes. That's why so many groups have been working on expanded gamut color spaces. Otherwise, why bother? There would be no use for them. Clearly, that is not the case.

--Rich Wagner

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Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "Andrew Rodney"

Wed Nov 15, 2006 8:05 pm (PST)

On 11/15/06 4:26 PM, "Dan Margulis" wrote:

Andrew Rodney posted a photograph that he claimed would benefit from use of

ProPhoto, but as it turned out sRGB, let alone Adobe RGB, would have been more

than sufficient.

NO, it©ˆs NOT! Did you output the file on a decent, modern ink jet? I have an Epson 3800 (and 2400) and there ARE colors in the image that are reproducible and visible on output that are clipped when using sRGB. If you edit the file in sRGB or Adobe RGB (1998) to do something as reasonable as boast the saturation or other edits, it breaks up in any working space but ProPhoto RGB. So I have an image that shows colors upon output and without degradation only by using ProPhoto RGB. This isn©ˆt at all complicated. You just need the right output device.

Your charts and your rhetoric seem to suggest that there are powerful

incentives for working in ProPhoto. If so, it would seem to be a simple matter

to produce a photograph that handles better when acquired in ProPhoto than

elsewhere. Until you can do so--and Andrew certainly can't--charts are

worthless.

Look do I have to send you output to prove that there©ˆs a visible difference on output to an Epson 3800 from a flower shot I submitted even without editing the files? I have a print, output at 2880 on glossy paper. The sRGB image doesn©ˆt show the subtle tones in the yellow and greens in the flower that the ProPhoto RGB image does. I didn©ˆt edit the file a lick, not even output sharpening! When I do that, the differences are even more pronounced. Is it night and day? No but anyone who buys prints and has an eye for color WILL see the difference. I prefer the smooth tones of this gentle flower in the ProPhoto image, detail that©ˆs simply not being output on the 3800 using sRGB.

I©ˆm not about to print out hundreds of images for anyone on the list and I suspect that even if Dan got my print, he©ˆd find some reason to dismiss it. But if anyone out there in Color Theory land doesn©ˆt have a modern Ink jet that produces the qualities of the K3 inks, ping me and I'll send you an 8x10.

You all have access to the files. Those of you who understand the differences in RAW and DNG, the differences in working space and output gamut and know how to output the files can do so and see what I see. If you can©ˆt, I'll provide a few prints. But there©ˆs no question there©ˆs a quality difference and this is a single image without a single edit. And yes, buy doing a slight saturation move, the ProPhoto image looks far better and yes, that edit does make the differences even larger. There©ˆs no reason why this image can©ˆt use such an edit if the end user (in this came me) feels it provides a better rendering.

Andrew Rodney

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Re: RGB Working Space, Part 2 of 2

Posted by: "Olivier"

Wed Nov 15, 2006 11:20 am (PST)

I must admit Dan has lost me too in the reply :

If you are planning to force a file into the deep magentas and cyans

that don't exist in photographs but are achievable on certain

printers, you will get better quality from LAB, but an ultra-wide RGB

may serve.

We surely do force those and others on occasions, for what we aim at is a better looking print not necessarily a more scene-realistic one, this is the way I went through the whole Lab book. I take for granted I did not understand Dan's point properly in this discussion.

Let's see if he (and others) is willing to further expand on the topic and eventually consider reviewing some Lab workflow hints and in this very issue the bit depth advocation given wide-gamut ouput or if he considers it is all non-sense.

Olivier Desmaison

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Re[4]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "Iliah Borg"

Wed Nov 15, 2006 11:29 am (PST)

Dear Rich,

Iliah,

The question of whether or not there are colors that can be printed

that do not exist in sRGB

I believe I never mentioned sRGB. I also believe you neglected to read my short post to understand what it is about. Maybe you can try what I said both with digital camera and with film.

BTW one can assume that all the colours from the target are resolved. That is not always the case.

Papers you linked are well-known here. I also know people who argue that sliced bread is the second best thing since ProPhoto. If they do not resort to personal attacks, accusations of other folks (successfully earning their livings in the same field) in being stupid, and differentiate opinions and hypotheses from facts and practice; if they do not try to break my workflow - it's OK in my book.

I'm very careful with my workflow. I'm not going to change it unless I fully understand the alternative and its benefits, and unless the alternative is a whole and consistent workflow, not a set of tips and tricks.

Just 2 weeks ago I was to ask to resign a person who nearly ruined the job because of his misunderstanding (and misuse) of ProPhoto. Out of curiosity I edited several files he ruined using ProPhoto. Shots were taken in Regent's Park, Queen Mary's Gardens, and were mostly of roses, some being very saturated red, some yellow, some are very dark purple; close-ups and views. I was sure it is doable and it turned out it really is. However the prints were the same as with my "normal" workflow, but I spent more time and effort. I gained nothing quality-wise.

Important lesson for me was that it is not colour space, it is the operator. I think it works in both directions. ProPhoto will not help poor operator (chances are he will end up with worse results compared to what he would be able in sRGB), sRGB is no big limitation for a good operator. Truth is somewhere in the middle, depending on the targeted printing process. Same as it is in photography - it is not the camera... you know the rest.

The gap between camera-making companies and ICC is huge. The gap between our understanding of camera colour characteristics and what really takes place there is also huge. At the moment those gaps pose the major problem. It took 2 years to guess that D1 CFA was designed with NTSC in mind. When we try to study spectral characteristics of modern cameras we may be coming to a conclusion that attempts to invent a colour space that will cover as much as possible of the imaginary camera "gamut" we may end up with Jack-of-all-trades, master-of-none.

Best regards,

Iliah Borg

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Re: Re[4]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Wed Nov 15, 2006 12:37 pm (PST)

On Nov 15, 2006, at 9:23 AM, Iliah Borg wrote:

I believe I never mentioned sRGB.

Iliah,

If you go back to my original post, my comments were all about the inadequacy of sRGB as a working space for inkjet printing - they had nothing to do with digital capture.

I also believe you neglected to read

my short post to understand what it is about. Maybe you can try what I

said both with digital camera and with film.

I read it several times, trying to understand what your point is, and how it relates to the discussion, started by Dan, about color spaces and printing. I'm not sure what you want me to do re: "see what colours are reproduced by the camera and how they are reproduced. But do not use invented colours coming from ACR or other raw processors. Look into raw data itself." The "raw data" are just numbers - not colors. Do you mean after the color mixing function, but before the data is committed to a particular gamut? I don't see how this has anything to do with the fact that printers can print colors outside of sRGB, and that those colors exist in photographs (scanned film or digital capture).

Do you agree that printers can print colors outside of sRGB, and that limiting the source image to sRGB clips colors that the printer could otherwise print, reducing the effective gamut of the printer? This is the real issue, and it is why sRGB is an inadequate color space for inkjet printing.

I hope this helps clarify what I'm talking about.

Best,

--Rich Wagner

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Re: Re[4]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "Greg Welch"

Wed Nov 15, 2006 3:35 pm (PST)

Thank you Iliah and Rich for a spirited exchange!

I understand it is important to match how an image looks on the monitor and how it looks on the screen. However it is not really possible since one is transmisive and the other is reflective. The whole exercise in icc profiling is a compromise at best. When not understood it can be a disaster. ie separating a sRGB when it was created in aRGB.

I think their are 2 problems here.

1. Monitors and prints are different. We (collectively) have not yet perfected a mathmatical translation that will perfectly equate reflective values with transmissive values. A dog can be dressed up to look like a cat but it will never look exactly like a cat.

2. Somebody had the great idea, that color work should be done in rgb, when it is actually printed in some variety of cmyK. :-) I do agree that it is a good idea since the monitor is an rgb device. This leads to many different results and many viewpoints all of which are valid to a point, none of which can be correct. Even if you were printing with a printer with perfect rgb inks only. !!! Transmisive vs refective !!! dog vs cat forgive my simplicity and bad spelling?

For what it's worth, I will share with you my solution.

I work in sRGB space for reouching and intial contrast and color correction. It makes no sense to me to have a color space that my monitor cannot show me.

Next I convert to my printers color which in my case is cmyK. ( I've been using Iris printers for fineart applications for over 10 years. I still do and yes this is my only source of income, so my quality is of utmost importance.)

Now the fun part for me. I work and correct from this point in cmyK. Simple right? Because the profile I'm using is reasonably good my starting point is good. I can push the image in more ways than could ever be possible if I could only correct in rgb. I'm lucky because I use Iris printers. I can do stuff that others can not. For all the Epson printmakers out there I mean no offense. You cannot understand what I mean unless you have fully explored the Iris technology. Most Iris printmakers have only touched the surface of what can be done.

I would like to know what Richard and Iliah do with their knowledge. Are you printers? Photographers? etc.? I respect both of your viewpoints and have considered them deeply. It might make a nice thread to explore how we all use colortheory to achieve what it is that we all do? Are we in search of Beauty? Have we found different paths which take us where we need to go? Thank you for your consideration in reading my post!

Greg Welch

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Re[6]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: "Iliah Borg"

Wed Nov 15, 2006 7:55 pm (PST)

Dear Greg,

I'm a photographer, and we prepare own shots for press run. I'm also a co-author of a raw converter, so I have some first-hand knowledge of what raw files are.

Files coming out of raw converter are untagged, or sRGB, or Beta RGB (see http://brucelindbloom.com/BetaRGB.html ), or in custom profile (studio shots). Inside the converter a linearized version of device-independent colour space based on keeping luminance and chrominance apart (similar to Lab) for demosaicing and tone/colour correction.

We profile our printers ourselves using two-stage approach. Preliminary target is measured, and then a custom target to address problems found in preliminary profile is generated. The process of generating the second target is pretty automatic, but for the final profile we use a lot of hand-tuning based on what we feel is right :). Results allow for pretty accurate soft proof.

The file is converted to Lab for final targeting, and based on softproof we correct it.

For regular CMYK (we print mostly in Russia and do not use SWOP) the process is essentially the same, but we trust soft proof much less.

One of the essential points in our workflow is that targeted editing

is done in Lab with preview in printer space.

Best regards,

Iliah Borg

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Re: Wide gamut printing

Posted by: "Mike Davis"

Wed Nov 15, 2006 7:59 pm (PST)

I defend no one with my reply, just a real world observation.

Unless I am shooting artificially colored fabrics or copying art, I find no images in my "natural" digital and transparency photo collections that require a printed gamut outside of the normal sRBG or CMYK color spaces. And, no, I don't shoot flowers as a professional or hobbyist. The only way I can conceive of needing the widest gamut of today's amazing printers is to hammer an artificial saturation into a common image, such as a brilliant sunset, to force it to colors that weren't originally recorded.

As I surf the web photo sites such as PBase, smugmug and such, I see a world of oversaturated images that seem to be the rage these days. That's not to say that others may want to print such gaudy, bright colors. Much of what I see is an attempt to create photographic images that attract less knowledgeable viewers, rather the same as a vintner makes a wine sweeter to cover the defects.

Dan comes from the world of CMYK printing. His color correction techniques are better and more natural that any other author that I've read (and my personal digital imaging library is extensive). There seem to be a few posters who insist on proving the host is dead wrong, rather than providing useful color management information for the rest of us who are still humble enough to admit less than total mastery of the craft. Dan has stated his opinion and biases, and provided admission of rare circumstances in which huge gamut workspaces have a place in professional printed work.

In my own printing with my super wide gamut Epson printers, I find no need to print outside of normal sRBG colors, even though the printer will print cartoons if I wish. The horsepower is there if I need it, but you don't need 400 horsepower to drive to work every day. For those of you who do use that wide gamut, perhaps only because it's there, I'll pass over most of your garish images until I find one that provides some photographic substance, unsullied by unreal colors. For the rest of you who are pros who must provide those gaudy colors for an avant garde advertising client, use the color space you need to please, and enjoy the trip to the bank. Can't we all agree to disagree?

Mike Davis

mldavis2 AT sbcglobal DOT net

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Re: RGB Working Space, Part 2 of 2

Posted by: "Stephen Marsh"

Thu Nov 16, 2006 10:48 am (PST)

Andrew Rodney wrote:

NO, it©ˆs NOT! Did you output the file on a decent, modern ink jet?

Andrew, I am not sure what Dan does to test things, but would you care to comment on my methodology? I would hate to be drawing wrong conclusions.

Open the camera raw file of the flowers at default as shot white balance/tint settings in ACR with my baseline default processing settings (no extra boosting of tone or colour, saturation, nr and sharpening at zero etc).

For the three images I get the following ProPhoto LAB readings in the yellow areas of the flowers petals:

The B channel 5x5 average range readings while in ProPhoto in Photoshop read as:

_MG_0126.dng - 12 to 92

Flower_06October18_001.dng - 28 to 88

MG_0178.dng - 15 to 96

When I convert from ProPhoto to sRGB, I get the following max. B channel reading for the key yellow petal areas:

92 - 90

88 - 86

96 - 93

So there is some desaturation in the LAB B values in sRGB compared to ProPhoto at the highest B value point. We know that perception is weak in the yellows and it is the more critical luminance variation that will often be the deciding factor and to a lesser extent the A channel hue variation. These B values are near the extreme maximum for yellow in SWOP TR001 conditions.

These are only numbers, conversion softproofing and actual output is more critical - but this initial evaluation obviously saves on needless output. The numbers don't lie...but the observers perception may!

If yellow saturation is increased, we will exceed the gamut of the monitor and have a poor clipped view of the result. We will need to use a good output profile to see what is really taking place via a softproof, or an actual print if it comes to that.

The same is also true of the image, if saturation is increased beyond what the working space can hold there may be undesirable consequences to image detail or quality.

There are also 'good' ways to increase saturation, within ProPhoto or sRGB that provide similar results - except for the 'minor' differences due to the size of the container. These 'good' methods treat the colour and or saturation component of the image in a separate fashion to the luminance. Comparing say the saturation slider of ACR, or the saturation slider of Lightroom, or the one in RawShooter one has similar results. One can also get similar results inside Photoshop when using the Hue/Saturation command's Saturation slider, by fading or using an adjustment layer set to either saturation or color blend modes. Then there is LAB mode, where one can use the HS command or edit the AB channels with curves or apply image to boost saturation.

The 'bad' way to do this saturation boost in Photoshop is to use the Hue/Saturation slider command in normal blend mode, where the result is not 'minor'. This poor result is solely attributable to using the H/S for saturation boosting command in normal mode and is simply overcome by blending to color or saturation blend modes. Moving to a wider container does help when using normal blend mode, but that is like saying it is better to shoot oneself in the foot with a .22 instead of a .44! The simple answer is to use color or saturation blend modes with the Hue Saturation command's saturation slider, even in ProPhoto and more so in sRGB.

You all have access to the files. Those of you who understand the

differences in RAW and DNG, the differences in working space and output

gamut and know how to output the files can do so and see what I see. But

there©ˆs no question there©ˆs a quality difference and this is a single

image without a single edit. And yes, buy doing a slight saturation

move, the ProPhoto image looks far better and yes,

that edit does make the differences even larger. There©ˆs no reason why

this image can©ˆt use such an edit if the end user (in this came me)

feels it provides a better rendering. <

The widest gamut output device I freely have access to is a large format HP5500 with CcMmYK unks, driven either direct (non PS) through the standard Windows XP print pipeline or via PostScript to a Colorbus Cyclone RIP. We use HP dye inks and OEM photo gloss or satin/semi gloss stock (MLT and ICC profiles supplied by vendor).

This RIP does not use ICC profiles for printing, but rather proprietary MLT clut's that access the extra inks (which current CMYK ICC profiles do not allow). It converts the standard incoming CMYK values to the lookup table values behind the scenes (TR001 being assumed for CMYK input). One can also feed the RIP RGB data or other flavours of CMYK.

The vendor does supply CMYK ICC profiles for various media and inks. The LAB 'B' value reading of 100% Yellow HP dye on photo gloss reads as 115. 100% yellow in TR001 reads as 95. So we can exceed the camera raw to ProPhoto gamut render in the yellow petals on this device, printing say from an ICC tagged ProPhoto RGB Photoshop PDF from Adobe (Acrobat) Reader 7 to the Cyclone RIP (our standard inkjet workflow is to funnel all prints from either Acrobat Reader or from MS Office software only [this is our shop's [my] preference only, the RIP is quite flexible]).

This should show the unedited differences between say sRGB, Adobe RGB and ProPhoto RGB. By then adding saturation or vibrancy boosting in Lightroom, one can push the test further.

Is this the sort of output test you had in mind Andrew? It is a modern wide format inkjet printer and RIP, costing the same amount as a new small economy car. The stock and inkset may not be up to your standards though (clients are corporate and small business, not fine art).

I don't expect any major surprises over my previous softproofing tests of these images and I think that it is all very subjective. I will attempt to do this testing before Christmas and report my findings.

Sincerely,

Stephen Marsh.

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Re: RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Thu Nov 16, 2006 11:03 am (PST)

John Castronovo writes,

With all due respect Dan, many of us don't only print "real photographs".

Understood and agreed. Such people have different needs from the rest of us. This, however, is a list aimed at color correction of *photographs*.

The suggestion has been made that members of this list should be using ProPhoto RGB as a working space. I understand that recommendation to apply to those of us who do only photographs and not to be limited to those who do other things. My response is that doing major edits in that space is likely to hurt quality. I do not mean that response to apply either to people who are doing non-photographic type work or to those who are using ProPhoto as some sort of interchange as opposed to editing space.

Just today I was scanning some artwork for the purpose of inkjet

reproductions. The original designs were created with Prisma colored

pencils and some of them are quite saturated. It's my job to retain as

much of the original color gamut as possible. My Betterlight scanner is

producing color that's way beyond what Adobe98 will hold and if I have

any chance of printing those colors accurately I feel that I have to use

a working color space large enough to contain them without clipping.

Right. So what you're doing is attempting to be faithful to the scan, and you're using ProPhoto as a convenient repository, which is perfectly reasonable. The edits you apply in ProPhoto, if any, are small. Similarly, I often acquire images containing bright colors in ProPhoto in order to take advantage of its channel structure in blending.

In flower images like the two I posted, a knowledgeable person does *not* try to match the original image, because the camera always records a larger area of brilliant color than the human visual system would. The objective is to confine the brilliance to a smaller area and then have a rapid falloff. That requires careful editing, and is where use of ProPhoto is apt to destroy the image.

Maybe I'm kidding myself though, so please tell me, is it your

contention that none of today's output (think about Lambda and Lightjet

Duratrans, film output, wide gamut dye inks on polyester media,

varnished canvas, etc. and not only Epson inks) is capable of taking

advantage of color gamuts larger than aRGB,

If you read my analysis of Vladimir's image, I stated that it contains critical color outside of the Adobe RGB gamut that can probably be achieved by certain output devices.

...or just that it doesn't

matter if they can because no "important" colors are in those spaces?

That's close to what I had in mind. Except for brilliant yellows as in Vladimir's picture, the colors that the extra gamut allows us to achieve rarely if ever occur naturally and so are not useful to photographers. The most common gamut problems in printing occur in pastel colors, reds, and yellowish greens. Adobe RGB is more than sufficient for any current printer in those areas. Photographs that might require more are readily recognizable and can be dealt with in ProPhoto on a case-by-case basis without accepting the colossal penalty of working in ProPhoto on the 99.99% that don't.

Dan Margulis

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RGB Working Space, Part 2 of 2

Posted by: "Andrew Rodney"

Thu Nov 16, 2006 11:03 am (PST)

On 11/16/06 6:01 AM, "Stephen Marsh" wrote:

Open the camera raw file of the flowers at default as shot white

balance/tint settings in ACR with my baseline default processing

settings (no extra boosting of tone or colour, saturation, nr and

sharpening at zero etc).

I simply set ACR to the defaults (out of the can, not custom which can be named "Camera RAW defaults" if you don't like the above). Note this isn't what I'd consider optimum for my 5D but wanted a setting that anyone could use. And the EXIF data should be in the .DNG if memory serves (or I can upload) making a case for ,DNG over RAW despite Dan's request for the 'straight raw'. So for example I see in detail pane, sharpening set to 25 but that's for preview only as set in ACR defaults (note, you can set ACR to sharpen the image or just sharpen the preview).

From here, I'm not sure if I can or should comment on your numbers since I'm not sure how you rendered the image. I can say that with these ACR defaults you can see on output a difference and advantage in the ProPhoto encoding. Edit the file or tweak the ACR settings, you'll probably be able to increase the differences even more (I'll try that too).

These are only numbers, conversion softproofing and actual output is

more critical - but this initial evaluation obviously saves on needless

output. The numbers don't lie...but the observers perception may!

Well since Dan is poo-pooing' Richards charts which are essentially numbers, I'm not going there <g>. The output is a more reliable indicator IMHO since in my tests, the output is defined (and Epson using K3 inks, glossy papers and using 2880dpi mode). Your mileage may vary based on any of the above variables. In my case, the differences are visible.

The 'bad' way to do this saturation boost in Photoshop is to use the

Hue/Saturation slider command in normal blend mode, where the result is

not 'minor'.

In the above cases, NO saturation tweaks were made. In my original email when I uploaded the files, I did a slight tweak and yes, the ProPhoto image doesn't fall appear like the Adobe RGB image even if we both agree it's not optimal way to up the saturation. I could have done this in ACR. That's not the point in this original test. The point is, there's no issue using ProPhoto RGB with one kind of correction while there is with the smaller space. That many expert users on this list would use another method to correct the image is moot when the point was, the larger gamut working space doesn't suffer the effects seen in the smaller working space. Point two is, using no edits, you can still see the advantages of a wider gamut space on output which is where the rubber meets the road!

In my mind, the two points show a decided advantage to encoding in ProPhoto RGB and a decided disadvantage to encoding in sRGB.

As to your ink jet versus mine, unless I see a gamut plot, I can't comment. I can't comment on how many more Epson K3 printers are in the hands of users than your HP (since you say it cost as much as a car, I'd suspect Epson has many, many more units out in the field). Lets not forget that you can pick up a K3 printer (2400) for $800. I would go out on a limb by saying there are probably more Epson K3 printers in the hands of users then every four color press on the planet. My point? There's lots of wide gamut ink jet printers cranking out color prints every day by lots of users who are Prosumer and up. This sRGB mindset is a disservice to this huge user base.

Andrew Rodney

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Re: RGB Working Space, Part 2 of 2

Posted by: "williamtheis"

---, DMargulis wrote:

No, I saw that one. It began, "WOW! I did the following simple

experiment. I did a capture into

AdobeRGB, converted to LAB and blew the colors out and then..."

This rendered the rest of the message irrelevant. In real life, we do

not deliberately blow out colors. Demonstrations that require

sabotage of images prove nothing.

First let me apologize for using the phrase "blow the colors out". This has obviously been confused. There was no intentional sabotage (note the word "intentional"). Here's what I did:

I selected an image of fall foliage (reds, greens, some blue water in the foreground--but not a real good test for blue) from an 8x10 Ektachrome scanned on a Heidelberg Tango Drum into J Holmes' Ektaspace 8bit. I then converted to Lab and applied curves that enhanced (to my eyes) the color to the levels I wanted, which admittedly are quite colorful given the scene. There were no, if any, areas showing a gamut warning on my display, calibrated with a Colorvision spyder. Then I did a perceptual conversion to BestRGB and printed it on an Epson 4800 K3 inks on Epson Premium Glossy. I went back to the lab version and this time converted to AdobeRGB98 and printed with the same printer profile, same paper. Everything was a constant except the conversion from lab going through BestRGB for one print and AdobeRGB98 for the other.

I was expecting this to be an experiment where the results were identical but had decided to test it anyway. So I use the word "Wow" to describe the difference. OK it's somewhat subtle but definitely the AdobeRGB98 looked garish and cartoonish next to the more natural colors of the BestRGB. (Your eyes might see it differently… they might not see any difference).

So I am putting BestRGB into my workflow in place of AdobeRGB98 since

1) it cost me nothing to do

2) there may be an image or two that it may help

3) I don't think that it hurts any image

Bill Theis

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RGB Working Space, Part 2 of 2

Posted by: "Andrew Rodney"

Thu Nov 16, 2006 12:11 pm (PST)

On 11/16/06 11:33 AM, "Dan Margulis" wrote:

In flower images like the two I posted, a knowledgeable person does *not* try

to match the original image, because the camera always records a larger area

of brilliant color than the human visual system would.

Look, if you©ˆre going to go down that rabbit hole, you need to educate the list and perhaps yourself about the vast differences in scene referred and output referred. Our visual system isn©ˆt anything like the linear encoded capture of a digital camera. And no matter how we capture the data, we have to produce an output referred image since the dynamic range and contrast ratio of the world as we see it and a display or print is incredibly different. Go outside mid-day and you might have a 10,000:1 contrast ratio. The best LCD might have a 800:1 ratio if you buy into the spec©ˆs (which I don©ˆt). Output on paper and maybe you©ˆll have a 500:1 ratio. So I don©ˆt see how you can start talking about matching an original, the way a camera captures linear data and how our eyes are using a totally different method of seeing the world. If your visual system worked anything like a digital camera, moving from a bright room into sunlight would make your brain explode and your eyes would catch on fire!

Might I suggest the following:

http: //www.adobe.com/digitalimag/pdfs/calibrating_digital_darkroom.pdf

http: //www.color.org/ICC_white_paper_20_Digital_photography_color_management

_basics.pdf

That's close to what I had in mind. Except for brilliant yellows as in

Vladimir's picture, the colors that the extra gamut allows us to achieve

rarely if ever occur naturally and so are not useful to photographers.

Not even taking into account, the above realities, how can you define what©ˆs a useful color to photographers? What©ˆs the matrix? I©ˆve asked if you©ˆve tested my flower image, or anyone else©ˆs image using the two encoding color spaces and simply OUTPUT THE FILE????

The most common gamut problems in printing occur in pastel colors, reds, and

yellowish greens. Adobe RGB is more than sufficient for any current printer in

those areas.

So you©ˆll supply a print that illustrates this? I©ˆm seeing issues with saturated colors (the lack of fine tone and gradations in real world images, output to a real world device) using smaller rather than larger gamut color spaces. You want the print?

Andrew Rodney

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "Lee Clawson"

Thu Nov 16, 2006 3:40 pm (PST)

on 11/16/06 3:46 PM, Andrew Rodney wrote:

If your visual system worked anything like a digital

camera, moving from a bright room into sunlight would make your brain

explode and your eyes would catch on fire!

For awhile now I wanted to write and thank you for all the recent posts but each time I wrote and sounded lame. With the above I can't resist. That happening to Dan is just to good.

Hope you have a good holiday........Lee

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Re: RGB Working Space, Part 2 of 2

Posted by: Andre Dumas

Thu Nov 16, 2006 7:15 pm (PST)

Stephen, Can you tell me where I can find MG_0178.dng, I have the other two but can't find that one.

Thanks,

André Dumas

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "stevej"

Thu Nov 16, 2006 7:52 pm (PST)

From: "Lee Clawson"

For awhile now I wanted to write and thank you for all the recent posts but

each time I wrote and sounded lame. With the above I can't resist. That

happening to Dan is just to good.

To carry this silly analogy to it's conclusion...

Gee, I didn't know memory cards exploded and sensor chips

caught fire if you took them into sunlight. Good to know!

Steve J.

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Re: RGB Working Space, Part 2 of 2

Posted by:

Thu Nov 16, 2006 7:54 pm (PST)

Adobe RGB is more than sufficient for any current printer in those

areas. Photographs that might require more are readily recognizable

and can be dealt with in ProPhoto on a case-by-case basis without

accepting the colossal penalty of working in ProPhoto on the 99.99%

that don't.

Care to elaborate on the colossal penalty? BTW, we typically work in DonRGB which is between ProPhoto and Adobe with a D50 white point.

john castronovo

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Re: RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Thu Nov 16, 2006 7:57 pm (PST)

Olivier writes,

We surely do force those and others on occasions, for what we aim at

is a better looking print not necessarily a more scene-realistic one,

this is the way I went through the whole Lab book. I take for granted

I did not understand Dan's point properly in this discussion.

I don't think you saw examples in the LAB book of colors being driven to extremes, except when the time allowed to work on the picture is so limited that you have to take short cuts. The strength of LAB is in dealing with subtle colors.

Having an overwide working space is dangerous when working with saturated colors. People who work such images either in LAB or any other ultra-wide space are asking for trouble.

Let's see if he (and others) is willing to further expand on the

topic and eventually consider reviewing some Lab workflow hints.

It is unusual to want to access colors that are both printable and outside of the Adobe RGB gamut. Except for brilliant yellows, these colors do not exist in nature, and cannot be captured by conventional photography. There may be legitimate artistic reasons to access them, but if so you are ordinarily creating a piece of impressionistic art rather than an attempt to reproduce a photograph, and it falls beyond the purview of this list or what I write about.

For anyone who nevertheless wishes to access these colors, I would recommend a second workflow path. If only an ultra-wide workspace can encompass them, then there is no alternative but to edit in one. It can be LAB, an ultra-wide CMYK, or an ultra-wide RGB. If all that is wanted is some accent, some touch of the additional color, then it won't much matter which one is used. If it is a gradual attempt to increase saturation, LAB is better, and if there is also a contrast issue an ultra-wide CMYK might be best of all.

However, all of these workspaces are so clumsy with very bright colors that I would recommend getting the image as close as possible to what is wanted in Adobe RGB or something equivalent first. Then Convert to Profile make the minor changes in LAB or ProPhoto or whatever. Other approaches risk seriously blotchy areas.

Using an ultra-wide RGB as a standard workspace to cater to these rare images strikes me as very like cutting off one's head to cure an attack of sneezing.

Dan Margulis

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Re: RGB Working Space, Part 2 of 2

Posted by: Andre Dumas

Thu Nov 16, 2006 11:22 pm (PST)

Hello Andrew,

This is not to reply to your message but it gives me an opening...:)

I did the following test using Andrew's image:

1- In ACR, take MG_0126.dng and optimize it for sRGB output @ 16bits 240ppi.

2- In ACR, take same and optimize it for ProPhoto RGB output @ 16bits 240ppi.

3- In Photoshop open each image separately and using Curves, select and set highlight and shadow points and steepen the composite curve. Optimize the curves to suit each image specific needs. *No* other corrections (no sharpening etc...), everything was done in the RGB color space, 16 bits, no resampling. I worked on an LCD monitor profiled with GM Eye-One Match 3. The final image was cropped for a 4x6 print.

4- Print both images on Epson's "Premium Glossy Photo Paper" with my 8 colors Epson R800 printer, using my custom R800 profile.

I did my best for both images and, quite frankly, I had no idea, nor did I care, which one would end up the better print (but I assumed that the ProPhoto would probably be the better one).

Some of the variables are: 1- My abilities in color correction, I'm not an expert but I've been doing this for the past 16+ years. 2- My printer; using a RIP would probably do a better print (?). 3- My printer profile (Monaco) which I'm sure could be better if I had a spectrophotometer. 4- It's impossible for a human being to color correct two images and do the best possible corrections for each image in a consistent way, if I had to this over again the images would probably be different again.

I examined both prints under a balanced 500K light for the overall appearance, also the details using a magnifying glass, I used gray mat boards to shield the images from my office environment.

I found that the colors (the yellows and reds) of the ProPhoto RGB image were deeper and more saturated than the sRGB image, this is obvious but only slightly (pleasantly) so, but that (in my opinion) did not make it a better image appearance wise. When I look at each image separately waiting 1 minute before looking at the other I could easily remember the differences in tone between the two.

The texture of the petals was more pronounced (better) in the sRGB image, the deeper yellow of the ProPhoto image hid some of that texture, if I had expected that to happen I probably would have been able to avoid it at some stage in the process.

The sRGB image has a more refined appearance, better details in the stems of the pistils, more details in the shadows of the yellows and the veins of the green leaf (touching the red flower) are better defined.

So in conclusion, at first sight they both look good, the ProPhoto stands out because it is more colorful but upon closer examination the sRGB has better, more subtle details overall.

These are my personal findings and opinions, it's all very subjective, I did not do this to please or displease anyone. My test just happened to give me the results described above. I'm sure that someone (with some expertise) could make any one of these two images better than the other one if that was his goal. That was not my goal.

André Dumas

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Re: RGB Working Space, Part 2 of 2

Posted by: "Stephen Marsh"

Thu Nov 16, 2006 11:51 pm (PST)

--- Andrew Rodney wrote:

From here, I'm not sure if I can or should comment on your numbers

since I'm not sure how you rendered the image. I can say that with

these ACR defaults you can see on output a difference and advantage in

the ProPhoto encoding.

Fair enough Andrew.

All I was trying to show was that at defalt settings that do not push the image further (it is not flat as in zeroed/linear settings, but it is not 'toned' significantly either, it is close to ACR defaults but not using auto) - that the flowers in either ProPhoto or in sRGB were within a couple of B values points of each other...nearly visually identical.

Obviously, if saturation is pushed, the near full sRGB container will overflow.

I presume that you had no problems with my overall evaluation method, rendering in ACR to ProPhoto and then in Photoshop using 5x5 LAB samplers to note the lowest and highest B value in the yellow flowers. Then converting the same image in Photoshp from ProPhoto to sRGB and reading the colour samplers. It is easy to see that sRGB is very close to the original scene gamut - only 2 to 3 B points difference.

The point is, there's no issue using ProPhoto RGB with one kind of

correction while there is with the smaller space. That many expert

users on this list would use another method to correct the image is

moot when the point was, the larger gamut working space doesn't suffer

the effects seen in the smaller working space.

We will have to agree to disagree here Andrew.

My position is that one should never use positive values in the Hue/Saturation's saturation slider in normal blend mode - whether in ProPhoto or a smaller RGB space. I feel that the edit is just as bad in ProPhoto, but it is somewhat masked by the gamut. I would continue to use color or saturation blends.

As normal mode does not behave like ACR, Lightroom, RawShooter or other software that separates the saturation from luminance - I don't consider normal blend mode to be what users *want* when they increase saturation. When one uses color or saturation blending modes, the command does compare well to ACR, Lightroom, RawShooter and LAB edits.

Your conclusion is that it is not the command, but the editing space.

My conclusion is that it is more the command being used incorrectly and that the editing space is secondary but still important (just not as important as using color or saturation blending).

Point two is, using no edits, you can still see the advantages of a

wider gamut space on output which is where the rubber meets the road!

This is what is interesting, as my non saturated quoted values indicate the the sRGB conversion from ProPhoto is only a few B points different, obviously slightly smaller in gamut but I wonder how much this will affect things as yellow detail is hard to spot for the human observer.

As to your ink jet versus mine, unless I see a gamut plot, I can't comment.

OK, if you want I can send you an ICC profile or a screen shot of a gamut plot compared to say TR001 SWOP, but as I stated earlier the printer does not use ICC, it uses MLT.

But reading 100% yellow with the gloss stock profile assigned, I get a solid yellow LAB B value of 115. which is approx. 20 points higher than the max yellow in SWOP.

What is the maximum LAB B value for 100% yellow if using K3 inkset and stock? Is it higher than 115?

I can't comment on how many more Epson K3 printers are in the hands

of users than your HP (since you say it cost as much as a car, I'd

suspect Epson has many, many more units out in the field).

I would tend to agree Andrew, I just drive it - I did not personally buy it! It is large format unit from the DesignJet range.

The HP5500 is around USD $10,000 - $15,000 (60 inch wide, 1.5 metres) add in another $5000 or so for the RIP if you wish to print PostScript instead of GDI (we also have UV inks, but one must swap out the entire ink system between dye and UV, incuding hoses, pipes etc). So it is even more pricey than I thought, as I thought that price was AUD, not greenback!

I don't know how accurate the ICC profile is, considering that we don't use ICC but rather MLT when printing. The ICC may indicate one thing, but the print may perform a lot better, gamut wise (I know conversion results are much better using MLT than ICC, but previews or LAB readings are unknown).

I think the ICC are just supplied so that one can hand them off to designers for softproofing if requested (we would recommend in most cases that data be presented as RGB instead of CMYK as converting to the HP ICC profile from the vendor does not have as good results as the custom MLT tables).

Regards,

Stephen Marsh.

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Re: RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Fri Nov 17, 2006 4:22 am (PST)

Dan,

I'll try to keep this short, so the List can move onto something else. I'm just trying to understand where you stand on RGB working spaces. No theory, no math, just what your recommendations are.

It is unusual to want to access colors that are both printable and

outside of the Adobe RGB gamut. Except for brilliant yellows, these

colors do not exist in nature, and cannot be captured by

conventional photography.

CIE L*a*b* is the most complete color model used conventionally to describe *all the colors* visible to the human eye. Lab pretty much describes what we, as humans, can see and experience in nature. Why are you stating that colors that are "printable and outside of the AdobeRGB gamut" don't exist in nature? Where does the data for this assertion come from? And how do you define "conventional photography?" Film? Digital? Both? Something else?

Which leads to my main question.

Are you now advocating AdobeRGB, rather than sRGB, as a working space for those doing fine-art inkjet printing? From what I've read in your books and on this list, it was my impression that you advocate the use of sRGB (not AdobeRGB) as a working space, regardless of the output destination. If I'm wrong about this, please correct me. I say this in part because in your Photoshop Lab Color book you state,"This book assumes for convenience that your default color space is sRGB (p. 18)." It is notable that you do not use or recommend the Photoshop North America Prepress 2 settings, which use AdobeRGB (1998) as the RGB default, even though it appears that your book is aimed largely at pre-press. You also constantly refer to "RGB" as a specific color space (e.g., p. 275 and numerous others) and a check of the numbers indicates that it's always sRGB. The few times you mention AdobeRGB it is to assign it as a "false profile" to an image in a smaller color space (p. 18) or to warn against "throwing it out to strangers" (p. 278 and others) or to disparage it ("Many professional photographers feel that sRGB is unduly limiting.... [AdobeRGB ] does waste a certain amount of real estate on colors that don't exist in sRGB." (p. 126).) I don't recall reading anything positive or beneficial about AdobeRGB (let alone ProPhoto) in the entire book.

Nor did I find any discussion of non-offset (non-CMYK) output in your book, although I don't have your latest one. In your recent RGB Working Space manifesto, you stated that,

Nobody advocates working in sRGB if you have an extended-gamut

printer; the only question is whether you should use something bigger

(meaning, to most people, Adobe RGB) or whether an ultra-wide RGB is

needed. It is, however, useful to *test* sRGB vs. ProPhoto, because

any problems Adobe RGB might have would be worse in the sRGB version.

If we conclude that sRGB is not sufficient, *then* we can look at

whether Adobe RGB is good enough.

Many photographers feel that sRGB encoding for fine-art output is woefully inadequate, AdobeRGB is usually pretty good, and ProPhoto is often (or at least sometimes) better. Do you agree that photographers should generally use AdobeRGB, or do you still feel they should use sRGB, and if so, why? (I think I can guess how you feel about the use of ProPhoto.)

Lastly, the Universal Photographic Digital Imaging Guidelines, V2 (www.updig.org) that were released last month make the following recommendations:

Open-ended uses: When the final use of an image is not known, such as stock photography, or when the client will make multiple uses of the images, best practice is to supply a file in the Adobe RGB color space, with the Adobe RGB profile embedded.

Inkjet and dye-sub printers: Use a wide-gamut color space, such as Adobe RGB or ProPhoto RGB, for the source space.

Do you disagree with these recommendations?

I'm trying to figure out where you stand on working spaces for photographers. After all, the RGB Working Space was the topic of this two-part manifesto, and even after all of the back-and forth thrashing about, your position is still not clear to me.

Thanks,

--Rich Wagner

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Re: Wide gamut printing

Posted by: "john castronovo"

Thu Nov 16, 2006 10:48 am (PST)

Your points are well taken, but I find that it's not just a few "cartoons" and "avant garde advertising clients" who are the ones who need extra gamut. Try a Vermeer who's blues and greens remain photographically elusive and forget about Warhol. I had to stretch his colors way into wide gamut territory before re-imaging them onto Velvia LVT which was the only film that could hold it.

Artists were using colors centuries ago that go beyond sRGB (they're not all "garish") and they and many photographers will continue to do so. Maybe it's not our choice to see the world that way, but I find it a daily occurrence that we have to push the envelope for them. Not on every image, but on something, somewhere in the spectrum, every day. It doesn't even matter what's actually on film or seen in real life either. If the artist wants a pure cadmium orange, a delft blue or a glowing chartreuse, then I have to try for it. Remember that all imagery is artistry of a sort, so there's no such thing as "real" color because it happens in our mind's eye and we're all different.

Most often, it's true that sRGB may suffice and it's safest, but all too often we need more. I see it as a real problem to have switch gears for each image and customer, so in our workflow we tend to rely on a larger gamut working space as a routine and we've learned to deal with any pitfalls which haven't really amounted to much. It's a good tradeoff for our work, but we'd all like that magic bullet that gives us the best of both worlds, and that's why we're here on this forum.

john castronovo

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Wide gamut printing

Posted by: "Andrew Rodney"

Thu Nov 16, 2006 10:53 am (PST)

Mike, its not about printing super saturated colors or cartoons. If you view my prints (or test this on your end), you©ˆll see a subtly of tones throughout the colors that are visible in ProPhoto RGB that are blurred (for lack of a better term) in sRGB. In fact I asked my wife, someone who knows very little at all about photographer which print she preferred showing her several samples. At first she didn©ˆt see much of a difference (as I said in my last post, it©ˆs not night and day). Then she started to look closely at the details and picked the ProPhoto prints every time saying Œit looks sharper©ˆ. It©ˆs not, its the Epson©ˆs ability to lay done tone and color that are available in one space and not the other. It©ˆs detail. Correlate that to someone that knows good printing or is buying a fine art print and the differences in the two expand. This isn©ˆt to say that using sRGB produces a poor print, not at all. Using the wider gamut working space to the printer provides a superior print simply because there©ˆs data being used that isn©ˆt in the sRGB file. I©ˆd be happy to send you a print but suspect you have the tools and the eye to see this yourself.

Andrew Rodney

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Re: Wide gamut printing

Posted by: "Lee Clawson"

Thu Nov 16, 2006 10:55 am (PST)

on 11/15/06 9:15 PM, Mike Davis wrote:

There seem to be a few posters who insist on proving the host is dead wrong,

rather than providing useful color management information for the rest of us

who are still humble enough to admit less than total mastery of the craft.

Mike,

I don't read anyone trying to prove right vs wrong. What I read more than anything else is a diligent work to see if anything is there. Holding anything up to this group's analysis takes ____.

You sound like you're satisfied with your prints. That's great. I'm not and continue to question all this stuff.

Lee Clawson

2/\V/\7 Studio

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Re: Wide gamut printing

Posted by: "Laurentiu Todie"

Thu Nov 16, 2006 11:02 am (PST)

"dead wrong" are fighting words

and the colortheory shouldn't be about fighting or

personal color tastes, but about… color

(including Ferrari red : )

Laurentiu Todie

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Re: Wide gamut printing

Posted by: Andre Dumas

Thu Nov 16, 2006 3:50 pm (PST)

Hello Mike, I am discussing such an image (*gaudy* as you mentioned in your message) with the photographer who posted it on Pbase, he sent me his original raw capture and I "corrected" it using the knowledge that I have gained from Dan's teachings.

It was easy, 5 minutes and I got those impossible greens back to where they should be -- "In the natural green of a plant, equal cyan and yellow would be impossible. DM" (Professional Photoshop 6 page 29).

Then I compared my correction against his saturated image and I had to agree that his version had punch, that it was artistically quite beautiful. Mine was numerically accurate but it looked bland and boring. That photo lended itself to the liberties that the photographer took, his representation of that image is an artistic statement that "less artistically inclined photographers" might not be able to make. Nothing wrong with artistic license Mike!

André Dumas

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Re: Wide gamut printing

Posted by: "Iliah Borg"

Thu Nov 16, 2006 7:54 pm (PST)

Dear André,

May I add that some photographers often try to take photos that do not need painting over with acrylic pigments. Instead they search for scenes and subjects and light. It seems to me that lack of "photographic substance" can't be compensated with sharpness, bokeh, or catchy colours.

When I was 9 I brought my Grandfather my first colour photo. I was extremely proud. In late 60's in USSR colour photos were very unusual. I said, look, grass is green, sky is blue, and cannas are red! He took the negative, printed it b/w and asked: "Do you see any photo here?" I'm very thankful for his sarcasm.

Best regards,

Iliah Borg ___________________________________________________________________________

Re: Re[2]: [colortheory] RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Thu Nov 16, 2006 7:23 pm (PST)

Rich Wagner writes,

My comments were in response to your statement that,

"We need to know whether colors are actually

present that the smaller RGB does not contain; whether any such

colors can actually be printed by any known device;

As I pointed out, the answers to these questions have been known for

a long time, and the answers are a resounding Yes and Yes.

You are repeatedly attempting to drag red herrings across the trail by stating that I am suggesting that inkjet printer owners use sRGB, and that I am denying that inkjet printers have a bigger gamut than sRGB.

The quotation above, as you can verify from the original post, referred to how we would know whether two specific images (Vladimir's and Andrew's) would or would not benefit from being opened in ProPhoto. As these images AFAIK have never been seen publicly before, it seems most unlikely that the answers can have been known for a long time.

The remainder of your post, having no images to back up your theories, is irrelevant. I again request that if you have no images to present, you take the theories to another list.

Dan Margulis

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Re: RGB Working Space, Part 2 of 2

Posted by: "Wai-hong Chung"

Fri Nov 17, 2006 9:54 am (PST)

Hi All,

I've found another example that justify the use of Adobe RGB as working space. That is when you view your images on an Epson P3000 or Epson P5000 storage viewer which support Adobe RGB and edit your image using an Eizo CG 221 LCD monitor. Please refer to the below web site : -

http: //www.dpreview.com/news/0609/06093004epsonp3000p5000.asp

However, if I print photos, I still prefer using small gamut RGB such as sRGB or printer RGB as working space.

Kind regards,

Wai-hong Chung from Hong Kong

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Re: RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Fri Nov 17, 2006 11:22 am (PST)

Hi Wai-hong,

I read your note below. The reason that Epson is bragging about

AdobeRGB support is because so many photographers use it, and because

on devices that do *not* support AdobeRGB (and instead assume sRGB or

use no color management) the colors on the display will look bad,

just like if you mis-assign a profile.

If you read the fine print on the link to the site you posted, the Epson device displays "88% of the Adobe RGB color space." For comparison, the volume of sRGB is about 69% of the AdobeRGB color space, so the Epson device is capable of showing colors outside of sRGB, but not quite all of AdobeRGB.

Just like the Epson monitor can display those "outside of sRGB" colors, many printers can print those colors. That's why so many photographers prefer to use AdobeRGB as their camera output space. The reason is primarily for printing - not display - because often all you can see on a monitor is sRGB or a little better than that, unless you buy a very expensive monitor like the Eizo that you referred to. (Even I won't cough up $5,000+ for the CG221. We use Sony Artisans and the CG210.) Epson's definitely got the right idea, though. They know what photographers are using (primarily RAW and AdobeRGB), and what they need to do to satisfy photographers' requirements (color management).

Best,

--Rich Wagner

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Re: RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Fri Nov 17, 2006 6:28 pm (PST)

Bill Theis writes,

First let me apologize for using the phrase "blow the colors out".

This has obviously been confused. There was no intentional sabotage

(note the word "intentional").

Fair enough. I did infer from the words that the sabotage was intentional. By your description, however, there was, er, *unintentional* sabotage.

I selected an image of fall foliage (reds, greens, some blue water in

the foreground--but not a real good test for blue) from an 8x10

Ektachrome scanned on a Heidelberg Tango Drum into J Holmes'

Ektaspace 8bit. I then converted to Lab and applied curves that

enhanced (to my eyes) the color to the levels I wanted...

This is the fundamental misunderstanding. You did not know whether those where the colors you wanted, because, based on your description of what happened next, you had driven the colors outside of the Adobe RGB gamut, which itself is much wider than your monitor's. So, your monitor was displaying something that had very little relation to the colors you were actually asking for.

which admittedly are quite colorful given the scene.

Right. Natural autumn foliage shows a lot of color variation but it is never a brilliant color--we don't even push it to the limits of the CMYK gamut in most cases, let alone that of an inkjet printer. If you want to do this for artistic reasons, fine, but it is not what the list usually thinks of in terms of color correction.

There were no, if any, areas showing a gamut warning on my display.

Photoshop would warn you if you were going to CMYK, but not to RGB--you're on your own to discover whether there's a gamut problem.

Then I did a perceptual conversion to BestRGB

and printed it on an Epson 4800 K3 inks on Epson Premium Glossy. I

went back to the lab version and this time converted to AdobeRGB98

and printed with the same printer profile, same paper.

I was expecting this to be an experiment where the results were

identical but had decided to test it anyway. So I use the word "Wow"

to describe the difference. OK it's somewhat subtle but definitely

the AdobeRGB98 looked garish and cartoonish next to the more natural

colors of the BestRGB. (Your eyes might see it differently? they

might not see any difference).

No, I would see it the same way. Here's what happened.

In LAB, as in ultra-wide RGBs, it's easy to create colors that are beyond the gamut of *anything*. You get no warning, as you have seen--just unsatisfactory results. That's why I caution against using LAB to increase the saturation of colors that are already brilliant, unless they contain no detail, which your leaves plainly do.

In the yellow-greens and reds of autumn, the Adobe RGB gamut is greater than that of any printer. If this weren't so, your BestRGB version would be more colorful than the Adobe RGB, not just more detailed.

The cartoonish appearance of your Adobe RGB version is typical of what happens when you go well outside of a colorspace's gamut. Given that, your LAB file was also substantially out of the printer's gamut. When that happens, some detail can often be saved by going to an intermediate space first, such as LAB to RGB to CMYK rather than LAB to CMYK directly.

Your BestRGB version therefore can be expected to look better than your Adobe RGB version, but it still is damaged goods because the input file still had to be smashed into the printer's own gamut. So, you would presumably have gotten a better result by making a more subdued version, converting it into Adobe RGB, and then adjusting it to be as intense as possible while retaining detail in each channel.

This is the normal procedure in RGB to CMYK, too. Many people make the mistake of trying to be sure that an intense color is so strong in RGB that it can't possibly print at less than the most brilliant color CMYK can produce. This doesn't work--it costs detail. The correct way is to bring it into CMYK at slightly less than the maximum brilliance and then make final adjustments there.

Dan Margulis

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Re: Wide gamut printing

Posted by: Andre Dumas

Fri Nov 17, 2006 10:21 am (PST)

Dear Iliah,

So now we know where you got that trait...! Iliah, if the Group will allow, will you give me your definition of "photographic substance"? I'm not being sarcastic it's just that I've heard so many, yours might finally be the right one (?)

André Dumas

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An Apology to Dan

Posted by: "Lee Clawson" Lee Clawson double_cloth

Fri Nov 17, 2006 10:24 am (PST)

For awhile now I wanted to write and thank you for all the recent posts but

each time I wrote and sounded lame. With the above I can't resist. That

happening to Dan is just to good.

Dan,

I writing to apologize. This was, and now has become more so, a very poor and unwarranted message on my part. Actually "poor" doesn't come close. What I had meant to do was simply send Andrew a private message. And obviously at your expense. You don't deserve this.

I'm sorry.

Lee Clawson

2/\V/\7 Studio

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "Pylant, Brian"

Fri Nov 17, 2006 2:09 pm (PST)

For awhile now I wanted to write and thank you for all the recent posts but

each time I wrote and sounded lame. With the above I can't resist. That

happening to Dan is just to good.

Wow. This is not even over the top, it's under the bottom.

If you guys hate Dan so much why do you bother coming here? Is it some sort of sadistic streak that you like to punish yourselves so? Just freakin' take it somewhere else so the rest of us don't have to look at it all.

BRIAN PYLANT

Manager, Electronic Prepress

:::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::

Disc Makers

7905 North Route 130, Pennsauken, NJ 08110

Toll free: 1-800-468-9353 ext. 5539

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "pacomarquezfoto"

Fri Nov 17, 2006 6:27 pm (PST)

At first I didn't know how to take this and thought I was reading it wrong. I figured this

was bad taste ribbing. But Brian's post confirms that I'n not the only one who read it as a

terrible thing to have been said.

I don't much feel anger but shame for what has been said and for those who have said it.

I share Brian's feelings and thank him for having expressed them.

Paco

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: Richard Wagner

Fri Nov 17, 2006 6:28 pm (PST)

On Nov 17, 2006, at 12:47 PM, Pylant, Brian wrote:

If you guys hate Dan so much why do you bother coming here? Is it

some sort of sadistic streak that you like to punish yourselves so?

Just freakin' take it somewhere else so the rest of us don't have

to look at it all.

Brian,

I was not involved in that post, but let me make it very clear that I don't "hate Dan." Heck, I've never even met the guy! I've bought and read his books (and those of many others), and I read his posts and those of others on this list (and many others). I'm passionate about photography - have been since I was 14 years old and had my first darkroom. I belong to ASMP, NANPA, SAA, PIA/GATF... and I read and study everything related to photography/reproduction that I can. I always have, ever since my first career as an offset pressman 10 million years ago.

Some of us disagree with Dan about some things that we feel are important - that's why we spend our time wrangling over these issues. Dan has a lot of good ideas and is certainly adept at Photoshop color correction, but Dan is at odds with the color community on many issues. Some who disagree with Dan no longer bother to spend their time here - Chris Murphy, Bruce Fraser, Marco Ugolini, to list but a few well-known names. That's a big loss to everyone here. Dan is also an educator, so what he says influences many people. Some of us feel that if what Dan says in contrary to the generally accepted view and practice, people should be aware of that and make informed decisions about their workflows. If we think he's wrong - yes, we argue. Dan's a big boy, and he can certainly hold his own. I'm far more interested in the truth rather than who "wins" an argument. This is an Applied Color Theory list, so "winning" a debate is irrelevant. Show me the data, show me the images, show me the math, convince me that you're right - regardless of who you are and what your "credentials" are.

So here's to Dan, Andrew, Andre, Wai-hong, Stephen, John, and all the others that stick their neck out here and engage in civilized debate - so that we can all learn something and improve our craft.

--Rich Wagner

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "Bob Frost"

Sat Nov 18, 2006 4:35 am (PST)

Brian,

If you guys hate Dan so much why do you bother coming here?

I come here to learn about applied color theory, but afaik the subject matter of the list is not confined to printing on presses. Vast numbers of professional and amateur photographers print on inkjet (or laser) printers made by many firms, and I'm not just talking about the small home desktop printers, but also the big ones that sell by the thousands to phtotographic studios and have to be delivered by lorry. Wedding photographers by the million, fine-art photographers, black&white photographers, all use these printers that have different properties and need different know-how to traditional prepress work. That is not to say there is no common ground between them.

I've been reading this list for some years, and have learnt a lot from both Dan and the other contributors. Long may they continue to argue about the best way to do this, that, or the other. Photoshop gives us many ways or achieving the same objective, and there is rarely one 'correct' way to do things.

I don't think you need to feel sorry for Dan; he seems to give as good (or bad) as he gets. And he is accepting some of the changes; just a bit more slowly than some others would like! I nearly fell off my chair when I read one of his posts saying that he did use ProPhoto now (for making masks, I think). If I go back to his posts of a few years ago, I'm not sure he would have accepted it had any uses.

And let's not forget that although a lot of the current argument is about ProPhotoRGB as a wide-gamut working space, wide-gamut spaces have been around and been used for years. Wasn't EktaSpace produced by Joe Holmes about ten years ago to encompass all the colors captured on Ektachrome film, which did not all fit into the smaller color spaces?

Bob Frost.

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The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Fri Nov 17, 2006 6:28 pm (PST)

On Nov 16, 2006, Dan Margulis wrote:

It is unusual to want to access colors that are both printable and

outside of the Adobe RGB gamut. Except for brilliant yellows, these

colors do not exist in nature, and cannot be captured by conventional

photography.

This is certainly open to debate.

In describing the running argument about what color spaces are appropriate for photographers, my wife reminded me of an image that she shot about a month ago for a scrap-booking club. They wanted a colorful image with "punch" and *very* strong colors that could be used as part of a large sign. Detail was irrelevant. It is the photographer's job to deliver the image the client wants - not to make judgments about whether or not they like the design or idea. My wife delivered.

Here is a link to one of the test images she shot, scaled down to 500 px. The subject matter was construction paper used by the scrap- bookers. The camera, a Nikon D2X. The file format - RAW.

http://www.wildnaturephotos.com/Private/ColorOfNature/

This image prints convincingly better from ProPhoto than it does from sRGB. The print from sRGB looks flat and anemic and lacks the deep, saturated colors of the ProPhoto-derived print. The file is included so that you can try it yourself. Remember, the client wanted "punch" and strong colors, and it is the photographer/designer's job to deliver. This is a real photograph - not a computer-generated graphic.

The image is out-of-gamut in both sRGB and AdobeRGB.

You can download and print the TIF on an 8.5 x 11 inch sheet of glossy paper (like Epson Luster) from ProPhoto to a profiled inkjet printer. Then convert the image to sRGB and turn the paper around and print it again. There is no comparison between the two prints. To take full advantage of the gamut of the printer, it is essential to use a wide-gamut color space.

--Rich Wagner

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: dave_cardinal

Sat Nov 18, 2006 4:46 am (PST)

This image prints convincingly better from ProPhoto than it does from

sRGB. The print from sRGB looks flat and anemic and lacks the deep,

saturated colors of the ProPhoto-derived print. The file is included

I printed the image both "as is" and converted to sRGB on an E4000 with a custom profile on micro Luster and didn't find overall changes. What I did find:

* First, I used Relative Colorimetric for the conversion. If you use (say) Perceptual then almost by definition the transform compresses the colors. That takes away from many of the colors in the image and does cause an overall "muted" effect with this image. By using RC I limit the "damage" to only the specific color(s) that are "in trouble." [When I did the experiment with Perceptual several of the colors did indeed become muted.]

* With RC only the orange band was affected when I did the experiment. The dark/light orange bands melded together, indicating that the bright orange is indeed far enough out of sRGB that it has to be changed. So absolutely there was an effect.

* The bright orange was driven from (216,103,3) in ProPhoto to (255,74,0) in sRGB and presumably would have gone "farther" if it could, so that helps confirm the visual/printed result that in sRGB it is clipped.

* While Adobe RGB seemed to be stretched to its limits, it looked pretty good, so while I sure wouldn't process this image in sRGB I don't know whether there is a reason to rule out Adobe RGB.

Random Note: There are many articles out on the web (and recommendations from various color vendors) to use Perceptual with photographs, but I think that blanket use of Perceptual can be just as harmful as not. Since typically perceptual tries to protect everything, sometimes it makes the wrong choices while RC is (IMExperience) better at protecting the bulk of the colors, although it will of course lose the relationship between extreme colors.

--David Cardinal

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Andrew Rodney"

Sat Nov 18, 2006 3:30 pm (PST)

On 11/17/06 9:37 PM, David Cardinal wrote:

Random Note: There are many articles out on the web (and recommendations

from various color vendors) to use Perceptual with photographs, but I think

that blanket use of Perceptual can be just as harmful as not. Since

typically perceptual tries to protect everything, sometimes it makes the

wrong choices while RC is (IMExperience) better at protecting the bulk of

the colors, although it will of course lose the relationship between extreme

colors.

I agree but not based on one intent©ˆs methods of gamut mapping versus the other. For one, profile don©ˆt know squat about images and one intent may produce a more desirable color appearance compared to the other. In this instance, the soft proof and the human visual system is better at making these decisions than a machine or instrument. 2nd, there©ˆs no standard in how one builds a perceptual intent. Any profile vendor can use any math to do this they see fit. And since the profile really has no idea of the source color space, there are always assumptions going on. My experience with lots of images converted primarily using the GretagMacbeth (Logo) color methods for building output profiles is 9 times out of ten, I prefer the soft proof using RelCol. But that©ˆs with my images, based on my taste, based on one vendors mapping of colors.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Sat Nov 18, 2006 5:45 pm (PST)

David,

Thanks for doing the experiment.

To be clear and to make sure everyone follows, you are talking about the conversion from ProPhoto-->printer profile, and sRGB-->printer profile. There will be no difference with rendering intents with the ProPhoto-->sRGB conversion, since both profiles are matrix-based and changing the rendering intent will have no effect on the conversion. (It's too bad that Adobe doesn't inactivate the rendering intent popup for those conversions where it is irrelevant.)

We see an even greater effect in the deep blues/purples than we do with orange. There is essentially no purple in the sRGB-derived image. This is born out by a comparison of the image data in printer space.

* The bright orange was driven from (216,103,3) in ProPhoto to (255,74,0) in

sRGB and presumably would have gone "farther" if it could, so that helps

confirm the visual/printed result that in sRGB it is clipped.

Agreed - the orange is not "maxed out" in printer space (or ProPhoto). It is possible to get an even stronger orange on the print.

* While Adobe RGB seemed to be stretched to its limits, it looked pretty

good, so while I sure wouldn't process this image in sRGB I don't know

whether there is a reason to rule out Adobe RGB.

AdobeRGB still does not cover the blues/purples of the printer gamut. I've added one last image so that you can see the data relative to the gamut maps of the printer and AdobeRGB.

We do agree that sRGB would not be a good colorspace to process this image in.

Random Note: There are many articles out on the web (and recommendations

from various color vendors) to use Perceptual with photographs, but I think

that blanket use of Perceptual can be just as harmful as not. Since

typically perceptual tries to protect everything, sometimes it makes the

wrong choices while RC is (IMExperience) better at protecting the bulk of

the colors, although it will of course lose the relationship between extreme

colors.

I agree completely. We use RC far more often than PER. RC leaves the in-gamut colors alone, and pulls the OoG colors to the gamut boundary. PER pulls everything in toward the center, so in-gamut colors shift as well. Neither of them, however, will push colors *out* to fill the gamut of the destination space. If the initial space is too small, that's where you're stuck.

I have updated the web page to include comparisons to AdobeRGB.

http://www.wildnaturephotos.com/Private/ColorOfNature/

Thanks again, David, for running the test on your printer, and for your comments.

--Rich Wagner

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "murraydejager"

Sat Nov 18, 2006 3:30 pm (PST)

Hi Everyone,

--- IRichard Wagner wrote:

I was not involved in that post, but let me make it very clear

that I don't "hate Dan." Heck, I've never even met the guy!

That's interesting to hear, I've often wondered what the relationship of the main participants of this list was and how you know each other. I sometimes have visions of two members crossing paths in an office hallway and having co-workers leaping in in an attempt to keep physical blows from landing!

but Dan is at odds with the color community on many issues.That's

a big loss to everyone here. Dan is also an educator, so what he

says influences many people. Some of us feel that if what Dan

says in contrary to the generally accepted view and practice,

people should be aware of that and make informed decisions about

their workflows.

Sometimes the greatest ideas come from people who don't go with the flow! Dan wasn't the first person to influence my thinking about these most controversial subjects in digital photography. I was interested in photography from a very young age but gave it up almost twenty years ago. I became interested again almost three years ago when the digital age really started encroaching on the traditional methods. Three years ago, for me, bigger was always better! More megapixels, more ram, more memory, you name it... More Was Better!

Then something happened. One of the first books I purchased was a book by Kevin Ames called "The Art Of Photographing Women." Right off the bat in his book he made it perfectly clear about the benefits of 16 bit vs. 8 bit photos. I was in total support with those ideas. Mr. Ames was kind enough to provide an example of the difference between 8 bit and 16 bit in his book. Look at how "the model's shirt is overexposed." "It is difficult to see the drops of water on her arm." Comments directed at the 8 bit version.

The only problem was I couldn't see the difference! I attributed it to the printing press. Now fortunately Mr. Ames was kind enough to include a CD with his book that included this particular photo example on it. Again, unfortunately, I studied the 8 bit vs. 16 bit photo, at all magnifications trying to see the differences. I couldn't see them!

Thus started my search for the truth! I started scanning and printing all my photos in 8 bit and 16 bit trying to see what everyone, at that time, was telling me was obvious. I never did see it. Almost three years later I'm still looking. Authors of almost every book I pick up tell me there's a difference...

On day I discovered an author by the name of Dan Margulis. For the first time I was reading someone telling me that there is No important difference between 8 bit and 16 bit in ordinary photographs, and most importantly, was telling me why. He could also tell me when 16 bit was better and even tell me that if I wanted to work in 16 bit all the time it wouldn't hurt anything.

An now the subject of working spaces is before us and once again I have found Dan's perspective on things to be the most neutral. Dan's not here telling me that if I don't work in the widest color space all the time that I'm wrong! He's telling me that for the most part a color space like sRGB is fine. Wider spaces have there place also, depending on the work one is doing, so they shouldn't be discounted. That perspective, in my opinion, is one of an expert or Master of his trade. If I have a photo that would benefit from a 16 bit, Prophoto workflow I use that workflow. If, however, the photo only requires an 8 bit, sRGB workflow that's the workflow I use. If a photographer uses a 16 bit, Prophoto workflow 100% percent of the time because he believes that will 'catch' most of what he does then, in my opinion, he's nothing but an amateur!

So if 99% of Dan's work requires an sRGB workflow and 99% of Andrew's work requires a Prophoto workflow that's what should be done... so what's everyone arguing about?

That said, when this list degenerates to, almost, the point of distaste and rudeness I seem to learn the most! There's always room for argument.

If we think he's wrong - yes, we argue. Dan's a big boy, and he

can certainly hold his own.

I agree, but I will add that I think Dan must have more than two Balls! And if I can't say that I'll change it to, more than two testestrone producing devices below his waistline! Who in their right mind would put themself in the position of being the 'Lone Wolf!'

So here's to Dan, Andrew, Andre, Wai-hong, Stephen, John, and all the

others that stick their neck out here and engage in civilized debate

- so that we can all learn something and improve our craft.

CHEERS,

Murray DeJager

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Re: RGB Working Space, Part 2 of 2

Posted by: "williamtheis"

Sat Nov 18, 2006 3:34 pm (PST)

first and foremost: thanks, Dan, for the guidance and "sensitivity training" to my gamut problem. I have read the Canyon Conundrum book at least twice (and some sections many, many times). It is so easy to get seduced into very attractive colors (read this "out of gamut") on my monitor but based on your advice, I intend to be much more alert to loss of detail when I get myself in trouble.

To ensure that I give myself plenty of "space" before sharpening, I intentionally work with an image that appears dim on the screen so that when I sharpen I do not run any part of the image to blank white when it prints. I would assume this would be good insurance when using the powerful tools of LAB, applying one last Levels layer to bring overall contrast to the desired range.

Another thing I have taken to doing is pasting the final LAB result as a layer on top of the RGB that was converted to LAB. Besides being able to immediately see what I have done in LAB, I usually change the LAB layer opacity to "tame" some of the LAB results back to adjustments done in RGB.

In spite of all these attempted safeguards, I am unfortunately still guilty of driving out of gamut colors in my images as many appear "cartoonish" to some extent.

It is disconcerting that the "Gamut Warning" for the monitor is not a good indicator that I have gotten into trouble. So the only thing to do is to look for loss of detail in the AdobeRGB98 channels? Or is there a better way to check for problems from the point of view of the printer and it's colorspace? (I assume that you may address this in the upcoming book)

Bill Theis

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Re: RGB Working Space, Part 2 of 2

Posted by: "Ric Cohn"

Sat Nov 18, 2006 3:36 pm (PST)

Now we're back to my (old) question of what working space would make sense if we started today with a clean slate. Dan, I know, has shown an aversion to recommending yet another working space (feeling, I believe, that this distracts from what he feels is important for his methods). However, I'm not sure that he wouldn't say that DonRGB is a good substitute for AdobeRGB. Maybe he'll comment on this.

Looking at the working space comparisons on Bruce Lindbloom's site http://brucelindbloom.com/ I see a huge difference in size between ProPhoto and DonRGB. DonRGB appears slightly smaller than BestRGB (mentioned in a previous post) and slightly larger than Bruce Lindbloom's own BetaRGB. I'm not so sure that these aren't all "reasonable" working spaces for a "normal" workflow. Another possible space is L*StarRGB which I believe is the same size as ECI-RGB but with an L gamma.

Does anyone see any reason one of these spaces wouldn't be a better choice than AdobeRGB for a "Wide Gamut" space? They are all better "shaped" than AdobeRGB, owing to the fact that AdobeRGB was created by mistake by extending the green primary, and they are all slightly larger, encompassing almost all the colors we're likely to ever need to print without going way beyond this point. Do these spaces have the same kinds of "dangers" of working in ProPhotoRGB with it's ultra wide gamut that is larger even than Lab?

Looking for educated opinions with the hopes of improving my own images.

Ric Cohn

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Re: RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Sat Nov 18, 2006 3:43 pm (PST)

Are you now advocating AdobeRGB, rather than sRGB, as a working space

for those doing fine-art inkjet printing?

As you must be aware from having read the materials you cite, I have *always* recommended that. You are the one who is trying to persuade the list otherwise.

From what I've read in your

books and on this list, it was my impression that you advocate the

use of sRGB (not AdobeRGB) as a working space, regardless of the

output destination. If I'm wrong about this, please correct me.

To quote the pertinent section of Professional Photoshop 4E (2002), p. 270: "The recommendations for the practical person, therefore, are as follows:...[for] Work primarily aimed at non-Web RGB: If you are certain that your workflow won't let anyone convert (or fail to convert) it improperly later, use Adobe RGB."

I say this in part because in your Photoshop Lab Color book you

state, "This book assumes for convenience that your default color

space is sRGB (p. 18)."

Correct. It also assumes that SWOP v.2 is the default CMYK. The explanation (p.44): "These settings are chosen only because more people use them than anything else, and not because I approve of them, *which I do not.*" [emphasis added]

The few times you mention AdobeRGB it is to assign it as a "false profile" to an image in a smaller color space (p. 18) or to warn against "throwing it out to strangers" (p. 278 and others) or to disparage it ("Many professional photographers feel that sRGB is unduly

limiting...." (p. 126).)

The use of false profiles is standard in color correction and says nothing for or against the space being used. The warning against throwing Adobe RGB to strangers is backed up by an actual image that seriously damaged a professional photographer's career when a printer ignored the Adobe RGB tag.

With respect to the "disparagement" of Adobe RGB on p. 126, you seem to have picked up with the second sentence of the paragraph--interesting that you should have missed the first. Here's the complete paragraph.

"This book assumes that our RGB is the variant known as sRGB, a choice of convenience, not an endorsement. Many professional photographers believe that sRGB is unduly limiting. Its definitions of the primary colors are relatively dull. Those who subscribe to this criticism generally prefer the definition Adobe RGB, which permits more brilliant colors at the expense of some subtlety. A few feel that Adobe RGB isn't wide-gamut enough and use an even more brilliant definition."

I see nothing in the above that defames either Adobe RGB or ultra-wide RGBs. I *do* see something that explicitly says I do not endorse sRGB.

I don't recall reading anything positive or beneficial about AdobeRGB (let alone

ProPhoto) in the entire book."

Nor about sRGB, nor Custom CMYK, nor SWOP v.2. It's a book about LAB.

Do you agree that photographers should generally use AdobeRGB, or do you still feel they should use sRGB, and if so, why?

There is no *still* about it. You know perfectly well I never said such a thing. Your recent posts to the group indicate that you believe if you only repeat nonsense enough times it will become true.

Lastly, the Universal Photographic Digital Imaging Guidelines, V2

(www.updig.org) that were released last month make the following

recommendations:

Open-ended uses: When the final use of an image is not known, such as

stock photography, or when the client will make multiple uses of the

images, best practice is to supply a file in the Adobe RGB color

space, with the Adobe RGB profile embedded.

Inkjet and dye-sub printers: Use a wide-gamut color space, such as

Adobe RGB or ProPhoto RGB, for the source space.

Do you disagree with these recommendations?

Re #1. In a perfect world I agree. In the real world, the high probability that someone will open the file as sRGB far outweighs any advantage of Adobe RGB. If the image is going to someone known to understand what an embedded profile is, fine. But as a *general* recommendation, it is a form of masochism.

Re #2. If the words "or ProPhoto RGB" are deleted, and if a clause is added making an exception for those photographers who have little control over who handles their files, then I agree.

I'm trying to figure out where you stand on working spaces for

photographers. After all, the RGB Working Space was the topic of

this two-part manifesto, and even after all of the back-and forth

thrashing about, your position is still not clear to me.

Said manifesto contains the following statement:

"Nobody advocates working in sRGB if you have an extended-gamut printer; the only question is whether you should use something bigger (meaning, to most people, Adobe RGB) or whether an ultra-wide RGB is needed."

In spite of this, you immediately started a thread titled "Is sRGB the ideal color space for fine-art inkjet printing in 2006?" as if anybody was arguing that, and you have repeatedly attempted to demonstrate since then that sRGB is not an adequate space for such printers, as if anybody had ever said otherwise.

Noting also that you have conveniently omitted the two disavowals of sRGB in my book (one of which you could not possibly have missed, since it was the sentence before the one you quoted), I surmise that my position *is* clear to you but that it you believe it to be in your interest to pretend that it is not.

Dan Margulis

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Re: RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Sat Nov 18, 2006 3:44 pm (PST)

André writes,

These are my personal findings and opinions, it's all very

subjective, I did not do this to please or displease anyone. My test

just happened to give me the results described above. I'm sure that

someone (with some expertise) could make any one of these two images

better than the other one if that was his goal. That was not my goal.

This is the expected result when a person edits in a larger gamut versus a smaller one. The tendency is toward brighter colors in one and more detail in the other. The same result occurs when one edits in RGB as opposed to CMYK.

I write simply to re-stress your point, in case anyone else is motivated to repeat this test, that if one result had turned out better than the other it might only show that you had corrected one more skillfully. That a less talented person might achieve a result that would favor either method would not prove anything.

Dan Margulis

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RGB Workspace and Artists Vision

Posted by: "Lee Varis"

Sat Nov 18, 2006 3:40 pm (PST)

Hi all,

warning, long post ahead – anyone anxious to respond to the points made in this post please do me the favor of reading the WHOLE post before responding (hint, I'm not anti-color management):

I usually avoid jumping in to these arguments about the best RGB workspace but I do follow the back and forth for entertainment value and the occasional educational tid-bit. This wide vs narrow gamut argument has been going on for some time and we are seeing a general trend towards "gamut inflation" as a sort of quality solution for serious imagers. This is certainly not surprising considering that the color quality of inkjet printers has continued to rise and wider gamut LCD monitors are starting to become available. The gradual emergence of high dynamic range imaging is also driving the concern over whether we are working in an appropriate environment to cover all possible applications for imagery which may be multi-purposed into unforeseen uses in the near future.

I think, however, that we should be concerned over a rush to accept inconvenient or certainly unnecessary workflows because the bar for ultimate quality in reproduction SEEMS to have been raised. Dan's arguments caution against using a workflow that has benefit for only a small percentage of imagery for everything you do because it can cause problems more often than it can solve them. I find it very humorous that so many proponents of wide gamut workspaces refuse to understand this and will go to great lengths to find an unusual image that demonstrates an advantage when nobody, AFAIK, has suggested that such images don't exist!

When we have an image that depends on extra saturated colors beyond the gamut of the more normally constrained RGB workspaces – of course we might want to utilize something like ProPhoto or Ektaspace even if we will ultimately be going to an output that is perhaps only modestly beyond Adobe RGB – IF "important" printable colors are not available in the normal workspace. It is my experience in the 20 years I've been working with digital imaging that this happens in maybe 1 percent of the cases with normal photographic subject matter. The key determination here is what is "important". This is very likely to be different from one person to the next so the whole issue becomes a personal preference based on your own aesthetic. If your artistic "vision" depends on driving colors beyond what might be considered normal you might want to consider how you can best take advantage of these wide gamut workspaces – but you have to be very aware of the pitfalls!

The artist has to ask "does using this or that workspace make it easier to achieve what I have in mind". IF all you're concerned with is bright saturated colors and "color" differentiation between such colors AND you're not going to be manipulating color and tone in any significant way ProPhoto just might be useful. I find a surprising number of photographers willing to accept these constraints and endorse this approach. This same group tends to rely on the gamut constrained monitor for all color evaluations but touts the ability of their inkjet printer to reproduce colors outside of the gamut of their monitor! Does anybody here see the humor in this situation?

I think the reason for this is that photographers historically have trained themselves to pre-visualize the end result without the benefit of an accurate preview during the imaging process. Photographers are predominantly concerned with the capture of images and most have not directly affected the image during film processing or printing as this was the domain of the lab. Historically, photographers have also been isolated from the commercial reproduction process as this has been the domain of prepress and offset lithographers. Thus, photographers as a group accept that they won't know exactly what something looks like until its printed. They take a picture, a whole bunch of things happen and then they see a print! This puts them in a position where they relate the input directly to the output and often simply accept or reject what they get.

Nowadays, of course, anyone shooting digitally can begin to see a reasonable preview of the image in progress starting with the LCD display on the back of the camera or computer monitor moments after the shutter has been released. Color management promises that you will be able to see predictable color all along the way from capture to print – how well this works depends a lot on whether the majority of your images fit into the gamut of the lowest common denominator in the chain of devices in the workflow. Photographers seem to be more comfortable with non visible colors in the intermediate steps of the workflow because they are not used to interacting with the image during this phase of the imaging process. This is all well and good if everything goes according to plan.

Of course the best laid plans of mice and men...

The digital revolution has granted the imaging artist unprecedented control over the image. If you want to fully grab the reins of this control you have to realize the limits of your ability to visually interact with the image and exercise control appropriately or abdicate control to some automated function. I have gradually become more and more comfortable exercising control over the image in more and more extreme ways and less comfortable abdicating control to automated transforms. This means that I tend to interact with the image before and after transforms from colorspace to colorspace and I don't like to wait until I see a print before I manipulate the image to my liking. Once I have the image where I like it , I am very unhappy if something changes even if its a fairly subtle change. By using color management and color correction techniques appropriately I've managed to reduce the number of surprises and I continue to do so for those things which come under my direct control. This has placed me in the narrower gamut workspace camp because I like to see what I'm getting on the monitor before I print it. I don't like flying blind even though I come from an old school photography background where that was a normal way of working. Once you have the control, its addicting and I find myself preferring to pretend that colors outside the gamut of my monitor don't exist because I have enough trouble controlling the colors I can SEE when when printing to devices which are basically unable to print a fairly wide range of colors that are visible in the color gamut of the monitor.

Yes, there are colors that the printer can print that are visible to the human and not on the monitor but I am completely willing to give up on those colors in favor of the control over the color relationships I can actually see on my monitor. I have recently migrated to using Adobe RGB as my standard workspace because I can now see most of that color gamut on my Eizo monitor! I find the trade- off between unprintable colors in Adobe RGB and printable colors in some wide gamut Epson/Lambda/Chromira/whatever... to weigh in favor of Adobe RGB as being the bigger overall color volume. I can see these Adobe RGB colors and so I can make informed decisions about those colors thus I prefer to avoid working in larger colorspaces (like ProPhoto) just because I can print a small percentage of colors for which I can make no decisions. Of course this is just my personal choice.

For most commercial work, sRGB is perfectly adequate (and easier to work in) because its closer in overall color gamut to most CMYK output devices and the areas where its deficient can be easily addressed once its converted to the output space. Many people would be better served for the majority of their "practical" work by adopting sRGB as a default – everyone is free to choose something else when its appropriate.

Many, it seems have a more religious view. They prefer to think in terms of scene-referred colorspaces and imagine that there should be some method of translating the original colors of a scene, as perceived by a human observer, "accurately" and any deviation from such is undesirable. This puts them into a position where they must have faith in color transforms that translate colors from one device to another when they encounter a device that cannot show the color encoded in a file. Since gamut compression/expansion technology is still imperfect we all have to accept a compromise somewhere along the way BUT this approach guarantees that that will happen closer to the end of the image creation workflow when you have fewer options. To each his own – this seems to work well for some people.

To end, (yes, I'm finally coming to an end here) I'd like to leave you with this idea as illustrated by a famous story involving Toulouse Lautrec. It seems that the famous artist was at a gallery opening for his work when an wealthy woman, a very cultured "patron of the arts" , came up to him and in a very insulted tone, while pointing at a painting on display said something like: " Monsieur, this woman's arm is way too big." to which Toulouse responded: " Madam, I think you are mistaken, this is not a woman!" Of course it wasn't a woman – it was a painting of a woman. The artist is permitted, in fact he is expected, to interpret reality through the filter of his imagination. For most this is easier when they can see the colors they are painting with and the resulting painting is valid even if the colors don't exactly match up with the image as seen in the natural subject.

regards,

Lee Varis

President, LADIG

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "David Marley"

Sun Nov 19, 2006 11:43 am (PST)

--- Richard Wagnerwrote:

The subject matter was construction paper used by the scrap-

bookers..

I can well imagine most of the colors in your file require a very wide gamut RGB space and output device. The issue Dan raised was regarding colors that exist in nature. Does this photo actually look like construction paper under normal lighting conditions?

Construction paper is a very coarse material, incapable of exhibiting strongly saturated colors. Most of the image is out of gamut on my display, but the few areas that carry detail show the mottled texture of construction paper's ground-wood composition. Can you provide some colorimetric values of the the actual subject to verify these colors as being true to nature?

David Marley

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "murraydejager"

Sun Nov 19, 2006 2:24 pm (PST)

Richard Wagner wrote:

This image prints convincingly better from ProPhoto than it does from

sRGB. The print from sRGB looks flat and anemic and lacks the deep,

saturated colors of the ProPhoto-derived print.

O.K. you guys Dan's comment referred to colors that exist in nature. I don't know where you guys live but maybe you should get out to the country more often. Pieces of brightly colored art paper, although made from trees, doesn't count as trees!

I agree though, this is a job for Prophoto!

Murray DeJager

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Sun Nov 19, 2006 2:25 pm (PST)

On Nov 19, 2006, at 12:24 PM, David Marley wrote:

Can you provide

some colorimetric values of the the actual subject to verify these

colors as being true to nature?

Please, let's not go there! I don't think this group needs to start using measuring instruments to prove points. I believe Richard made clear that it started as a photograph and had the saturation boosted way up to satisfy the *client*. However, I don't disagree that this image has been sent into colors that are more "artistic" than "real". Printing it out in sRGB is either 1). a good way to show the disadvantaged of using too small a color space or 2). is setting up a "straw dog" which no one is arguing against. I prefer to concentrate on #1.

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Sun Nov 19, 2006 2:35 pm (PST)

Thanks for posting this image. Other than calibration targets, I don't think I've ever printed anything quite this saturated, so I've never had this good of an example image to use to look at the gamut of my printer. I would say that although it started as a photograph, I question whether after the saturation boost it still qualifies as a photographic image. However, for this test I believe that's beside the point.

I printed it on my glossy paper using my custom profile (from ColorVision's PrintFix Pro) for my Canon i9900. I printed ProPhotoRGB, sRGB, AdobeRGB and L*StarRGB using Saturation mode. I used saturation mode because that is what I would normally do if I was looking for maximum color (I believe that unlike some Saturation mode profiles, the ColorVision built Saturation profiles don't blow out detail, they just go for the maximum color gamut from the printer at the expense of accuracy). The loss of color in the sRGB image is dramatic, if not surprising. However, between the ProPhotoRGB and AdobeRGB images I can only see a slight difference in the bright orange stripe. It makes sense that my printer would do well with this color since one of the extra inks with this printer is a very orangy- red. I can't see any difference between the ProPhotoRGB and the L*StarRGB prints.

I'd say this proves that my printer can reach colors way outside of the sRGB gamut and slightly outside the AdobeRGB gamut. Not exactly a shock, but it does help for me to see the difference with my own eyes. Of course, this doesn't "prove" that it makes sense to use ProPhotoRGB as your normal working space. From this thread, I feel better educated about when it makes sense to go to a wider gamut space, but unconvinced about the advisability of using an ultra-wide gamut space as a normal working space. Are you really advocating ProPhotoRGB as your normal working space? Do you believe that the "downsides" that Dan and other's have claimed for using an ultra wide gamut space are inconsequential?

I also continue to wonder if AdobeRGB is really the best "Wide Gamut" RGB choice. IMHO, sRGB makes sense for a Small Gamut space and ProPhotoRGB seems to make sense for an Ultra Wide space. Both of these are well thought out spaces. I also think it makes sense to have narrow and wide spaces available in one's arsenal to fall back on., But I still can't believe that there isn't a better choice than AdobeRGB for general photographic image editing.

Ric Cohn

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Andrew Rodney"

Sun Nov 19, 2006 10:35 pm (PST)

The LAB color space is significantly larger overall than ProPhoto RGB! Yes, the blue primary falls outside human gamut and thus LAB. But there are a heck of a lot of colors otherwise that fall outside ProPhoto RGB gamut.

Andrew Rodney

http://www.digitaldog.net/

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The Color of Nature: ProPhoto vs. sRGB

Posted by: "Andrew Rodney"

Sun Nov 19, 2006 10:36 pm (PST)

On 11/19/06 2:35 PM, "Ric Cohn" wrote:

Of course, this doesn't "prove" that it makes sense to use

ProPhotoRGB as your normal working space.

Why not? Who's provided a 16-bit file in ProPhoto that shows it's a problem? If you don't know the gamut of the image and you're not about to plot every one in ColorThink to decide the most appropriate encoding color space, why not go with one that will always have the gamut to contain the image?

Andrew Rodney

http://www.digitaldog.net/

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Sun Nov 19, 2006 10:38 pm (PST)

On Nov 19, 2006, at 5:48 PM, Andrew Rodney wrote:

Why not? Who's provided a 16-bit file in ProPhoto that shows it's a problem?

Well, your 16-bit limitation is a big one, but I'll accept that for now. Perhaps when CS3 comes out and I'm working on a dual-quad chip Intel G5 there really won't be a significant performance hit to my normally 100Mb to 1Gb (and up) 8 bit files.

Take away the argument for not working totally in 16 bit (or perhaps for not working on ProPhotoRGB files in 8 bit), do other's see a disadvantage to working in such a huge space (particularly when I normally work with relatively subtle colors and corrections)? Dan cautions about the limits to accurately setting colors or tones too exactly in Lab. I've seen for myself the advantages of making final corrections in RGB or CMYK. Why wouldn't ProPhoto with it's gamut that exceeds Lab's in some directions carry the same caveat?

Unfortunately, these kind of claims have shown themselves hard to prove. When someone posts an image and a correction that does or doesn't work, it's rare that it can't be improved by someone with more skill or time using an alternative method. I've seen and heard of many examples of images ruined by people working in ProPhotoRGB (and even AdobeRGB) due to poor technique and sloppy handling of color and tonal corrections.

Just because the blade is sharper doesn't *necessarily* mean it's more likely to injure an experienced and careful worker. On the other hand, a power saw with it's safety guard removed is inherently dangerous and a good tool used for the wrong purpose can ruin a job. So, which is it? I don't think anyone is arguing that ProPhotoRGB is never a suitable choice so I see two reasonable arguments to be made: 1). More advanced, but suitable for every use, or 2). A sometime tool (with the when and how much still TBD). Other's may see other choices as well.

Andrew's given his view. What do other's say?

Ric Cohn

___________________________________________________________________________

RGB Workspace and Artists Vision

Posted by: Clay Tomas

Sun Nov 19, 2006 11:44 am (PST)

Lee,

Thank you for the insightful post.

Clay Tomas

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Re: RGB Workspace and Artists Vision

Posted by: Andre Dumas

Sun Nov 19, 2006 2:34 pm (PST)

Dear Lee,

I read the entire post (more than once and I'll want to read it again a few times, I'm sure) and my reaction is that I agree almost one hundred percent with everything you wrote. In fact I wish I had written that post myself. If only I had your talent with words!

You touched (my interpretation) upon how photographers have been isolated from the initial process and how, traditionally, their main focus on the image has been "after" it has been captured, and how they have gotten used to take what they were given by the lab (the negative/print).

But now that they are involved in what used to be the domain of the prepress artists don't you think that, on this list, somewhat more emphasis should be given to discussions about the initial capture, perhaps starting at the raw level? It would also be nice if we could (on tiptoes) talk about getting better raws ...

Since neither Dan nor you nor most participants in the group (?) are "anti-color management" my hope is that, if profiling the raw is a possibility (good or bad) then that subject should be, eventually, considered on-topic for the group.

André Dumas

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Re: RGB workspace and artist vision

Posted by: "Mike Davis"

Sun Nov 19, 2006 2:24 pm (PST)

I like Lee Varis' reply. I'd like to add a bit of my own perspective to that.

There seems to be some reverent respect for the "original" image that comes from our cameras or scanners or film that has been held above the argument of switching color spaces, digital editing and the like.

When we stop to think of the differences between the real original scene as viewed before capture and the final print, there are a multitude of factors that strip away the "holy" pixels that "exactly" recorded the real image. We all know the variables: light temperature, sensor response, lens aberrations, RAW conversion to visible image, etc. We then take this "engineered" representation of what we captured as a "perfect" original, to which we might do irreparable damage should we tweak it (optimize it) in our digital image editors, evaluate it on our limited gamut RBG monitors, and send it through yet another series of RIP calculations to our wide gamut RGB printers using C+M+Y+K+ inks.

What we finally print cannot help but be an "artist's vision" of the original image. Artists take liberties with the captured image because we see far more than the camera/scanner can see. Eyes adjust for light/shadows, focus selectively on one area at a time, and pick out areas of texture and color as the image works on our senses. The path that a printed image takes is irrelevant if the end result is favorable. Ultimately, what we care about is how that image appears to the artist responsible for its final appearance. We have long since lost any correlation to significant pixel content in the original. Even a simple Photoshop exposure or white balance adjustment will change nearly every pixel value in the image. Significant (original) pixels are largely irrelevant if the final print is what the artist wants the viewer to see. This is perhaps one of the few instances in which, for many of us, the end justifies the means.

Mike Davis

mldavis2 AT sbcglobal DOT net

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Re: RGB Working Space, Part 2 of 2

Posted by: "Olivier"

Sun Nov 19, 2006 2:28 pm (PST)

I have read, re-read and again the past posts. The 5th edition is hopefully about to be on its way to my place and I might find some of the replies I'm searching in it.

However, as far as I am concerned, I don't manage to have a clear understanding of what is Dan's thinking and recommending for modern LFP printing. Would you please care, Dan, expanding again further on what is your view of best correcting images for modern LFP output.

Olivier Desmaison

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Re: RGB Working Space, Part 2 of 2

Posted by: "Olivier"

Sun Nov 19, 2006 2:29 pm (PST)

One thing I have been repeatedly taught was: stay as much as you can away from low gamma spaces for the value distribution will not help editing the image.

Olivier Desmaison

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "Pylant, Brian"

Mon Nov 20, 2006 8:26 am (PST)

At first I didn't know how to take this and thought I was reading it wrong. I figured this

was bad taste ribbing. But Brian's post confirms that I'n not

the only one who read it as a terrible thing to have been said.

Exactly. There were several replies on-list, and several directly to me. Several of which made really good points, and unfortunately I do no have time to reply to each of them individually (I am incredibly busy this week, since we're only open three days). But I stand by my statement: regardless of how you feel about Dan's work or writing, that was an absolutely AWFUL thing to have said about another person, that it would be "too good" to see harm come to him.

That was all I was commenting on, and if anyone took it any other way I do apologize for that.

Most of the time the disagreements on this list, while sometimes pedantic and overly-argumentative (from both sides!), are just disagreements, and on a subject as complicated as this there is room for many points of view. No, I don't think Dan is always right. Dan is not always lovable. Sometimes he draw much too fine a line in the sand in regards to what his methods (and, in turn, this list) is appropriate for.

But that comment was just too much to let go.

It's too bad that so many people in this modern work like to hide behind their keyboards and say whatever they want to, with no real-world repurcussions. Would Lee have said that to Dan's face? I think not.

BRIAN PYLANT

Manager, Electronic Prepress

:::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::

Disc Makers

7905 North Route 130, Pennsauken, NJ 08110

Toll free: 1-800-468-9353 ext. 5539

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Mon Nov 20, 2006 8:27 am (PST)

Ric, Lee, Oliver, Andre, Murray, Mike, and David (and others),

Thanks very much for taking the time to look at and print the image I posted, and for your thoughtful, and thought-provoking comments. Lee, thanks in particular to you for getting us off to a good start by putting what we do as photographers/artists into perspective. The ultimate goal is seldom a mechanical reproduction of the world around us - unless you're shooting for Google Maps.

On Nov 19, 2006, at 2:35 PM, Ric Cohn wrote:

Thanks for posting this image. Other than calibration targets, I

don't think I've ever printed anything quite this saturated, so I've

never had this good of an example image to use to look at the gamut

of my printer. I would say that although it started as a photograph,

I question whether after the saturation boost it still qualifies as a

photographic image. However, for this test I believe that's beside

the point.

Correct - it's completely beside the point. The point was to show what your printer is capable of - if you unleash it. If all you ever send to the printer are numbers appropriate for a display, the printer will never show you what it is capable of printing. sRGB encoding leaves a large percentage of the typical inkjet gamut untouched - great saturated colors that never get printed. It takes an encoding space that encloses the printer space to fully drive the printer.

Andre wrote (of Lee Varis):

You touched (my interpretation) upon how photographers have been

isolated from the initial process and how, traditionally, their main

focus on the image has been "after" it has been captured, and how

they have gotten used to take what they were given by the lab (the

negative/print).

Andre, you hit the nail on the head. In many ways, photographers have been stuck with the 12-pack of Crayons, instead of the 250-pack that oil/watercolor/acrylic artists have had. What many haven't realized is that they've had a 50-pack all along, but they've only been using 12 crayons out of the pack, and a 100-pack was right under their nose.

A few photographers have not been satisfied with even the 100-pack of crayons, and they've pushed the envelope. My friend Marco Ugolini recently reminded me of Bill Atkinson's work. Bill Atkinson is the former Apple programming wizard, and an incredible nature photographer. Not only did Bill decide that current inkjet ICC profiles were inferior, he built better ones and supplied them to photographers, for free. To make his unbelievable book, Within the Stone, that won a Gold Ink Award for excellence and innovation in printing, Atkinson worked with Vanfu in Japan to achieve a breakthrough in wider gamut printing from a standard offset press. They used highly concentrated inks, optimized ink densities, hybrid screening, high quality paper, and accurate color management to increase the total gamut volume by 1.6, which allowed his exquisite photographs of gem-quality rocks to print beautifully. They achieved higher quality printing at lower cost by using color management instead of expensive trial and error on press, and they developed methods that they feel can be applied to other offset presses.

Every color that can be perceived in the mind's eye is a color of nature, and Atkinson' s images show colors that are nearly surreal. If you've never seen his work, spend 5 minutes here (realizing that the colors are limited to the gamut of your display!): http:// www.billatkinson.com. To view the profiles and profiling targets that he has made available to all of us, go here: http:// homepage.mac.com/billatkinson/FileSharing2.html. Lastly, to view a great little PDF on how the book, Within the Stone was made, including hundreds of images of gem-quality rocks, click here: http: //preview.tinyurl.com/ykxqur Between them, you'll find every color possible in Lab.

Murray wrote:

O.K. you guys Dan's comment referred to colors that exist in nature. I

don't know where you guys live but maybe you should get out to the

country more often. Pieces of brightly colored art paper, although

madefrom trees, doesn't count as trees!

Murray,

I spend far more time in "nature" than most - whether that's camping in the jungles of Costa Rica or Ecuador, or in my own 5-acre backyard next to Saguaro National Monument East. I just pulled 2 mating rattlesnakes out of my photo studio last week - after thinking what a strange noise my Exobyte tape backup drive was making! And no, I hadn't brought this pair in there - they arrived on their own accord. We had a bobcat on the porch the day before, and we go through 100 lbs of birdseed a week. We know nature and the colors of nature.

The colors of nature are limited only by what your eyes can see and your brain can perceive. The gamut of human vision is roughly mapped out by CIELAB - and the colors of Lab may show up in an arc-welder's torch, or a Peruvian weaver's deep purple and lavender yarns, or in the eyes of a Red-eyed Treefrog, or even the light pastels of the artist's pencils that John Castronovo described working so hard to faithfully reproduce. As John described, it's his job to reproduce the artist's vision to the best of his abilities. The artist (usually) doesn't care about the tools or tricks needed to get the job done, and s/he doesn't want excuses about inadequate tools. Find a way! Push the envelope! Experiment! If all you say is "it can't be done" it never will be - unless someone else decides to try something new. Let that someone else be you! But, hey, maybe you're already there, because you recognized that this was a good image for ProPhoto. Bravo!

Mike wrote:

What we finally print cannot help but be an "artist's vision" of the

original image. Artists take liberties with the captured image because we

see far more than the camera/scanner can see.

And that's the bottom line. The recognition of "image states" is relatively new to photographers- it's just been the past 7 years or so that Kevin Spaulding, Edward Giorgianni, Thomas Madden, Jeoffrey Woolfe, and other "outside the box" color scientists at Kodak showed that it is critical to know whether the encoded RGB data of an image represents the color of a scene or the color of a reproduction of a scene, because the colorimetry of a scene generally does *not* equal the colorimetry of a pleasing image. Scenes are almost unlimited in variability and range of brightness and colorfulness. Any rendered image, or output state image, has the limitations of the media , as well as the issue of viewer preferences for contrast, colorfulness, "artist's vision," etc.

For anyone trying to understand the relationship between scene data (what the camera sees), camera raw data (what the camera records), and digital image files in an output-rendered state like sRGB, AdobeRGB, or ProPhoto, ISO-22028-1:2004 is a very useful document. It reads more like a book chapter than a specification. It's just too bad that the "information highway" is so expensive - it's a $125 PDF download. http://preview.tinyurl.com/y7waj3

Here's the abstract:

ISO 22028-1:2004 specifies a set of requirements to be met by any extended-gamut colour encoding that is to be used for digital photography and/or graphic technology applications involving digital image storage, manipulation and/or interchange. ISO 22028-1:2004 is applicable to pictorial digital images that originate from an original scene, as well as digital images with content such as text, line art, vector graphics and other forms of original artwork. ISO 22028-1:2004 also describes a reference image-state-based digital imaging architecture, encompassing many common workflows, that can be used to classify extended colour encodings into a number of different image states. However, ISO 22028-1:2004 does not specify any particular workflow(s) that are to be used for digital photography and/or graphic technology applications.

Lastly, I hope this exercise has allowed some on this list to realize that there can be a lot more color information in an image than what is seen on a display, and that it is possible to print this information on an inkjet printer. Images with bright colors like oranges benefit, as do images with deep greens and rich blues and purples.

Like many of you, I distribute most images to clients as 8-bit, aRGB TIFs, unless they request otherwise (16-bit, or CMYK, etc.) or unless there's a good reason to give them something else based on their intended use. (They would also get a list of do's and don't's, as well as a phone number.) Most of our scanned image collection is in aRGB, but all of our newer digital capture masters are in ProPhoto. When printing images on our Epson 9600, for some images we're gone back to re-scan the originals to scanner space, then converted to ProPhoto to regain the full gamut of the original transparency. Sunsets, in particular, become more vibrant, as do the deeply colored reflections of ducks in ponds, for just two examples. Most images print fine from aRGB, as was noted by David Cardinal and John Castronovo, but it is useful to keep an eye out for those that would do better in a wider gamut color space, as was noted by John. We've decided that it's worthwhile to use 16-bit ProPhoto as an output conversion/archiving space, and we haven't run into the feared ProPhoto boogeyman. Images go onto a 2 TB RAID and get backed up onto tape, with multiple levels of redundancy. The cost of storage is trivial compared with the cost of producing the image and the amount of time invested in each image, whether that's keywording or color correction.

I'll end with a shameless plug for Steve Upton's ColorThink Pro - a great tool for anyone interested in color reproduction and color management. If you want to "follow the colors" through image transformations, it's indispensable. Way cool, and no, I get nothing from Steve Upton or Chromix for plugging it, other than the satisfaction of having recommended a great product.

Best,

--Rich

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Stephen Marsh

Mon Nov 20, 2006 8:27 am (PST)

Ric, I recently found this link again, I downloaded the raw file years ago for evaluation purposes - but forgot where.

As I don't have access to good test images for saturation and detail, this is one image that I have often used over the years (one can easily recolour to test different hue combinations, increase saturation to test various profile gamuts etc).

http: //www.outbackphoto.com/workshop/NEF_conversion/nefconversion.html

(click the photo to download the raw file archive)

With all controls set to zero in RawShooter and only accepting the suggested camera whitepoint and exposure (so not attempting to jack up the contrast or saturation over the camera's native capture) - a flat no detail area of the orange feathers has a high B value of 95 in ProPhoto. This does not drop when going to Adobe RGB and stays the same value. In a conversion to sRGB, this drops to around 84 (10 points below max, so post conversion edits may be required if one wishes to push saturation to the max in the new space).

Rendering in ACR with slightly more 'toned' settings the B value in the orange feathers goes up to around 114.

In TR001 'SWOP' CMYK, the max yellow saturation would be 95 and adding any magenta or other inks tones things down further. While in sRGB yellow maxes out at 93 B. Adobe RGB is 104 B for saturated yellow.

As an unworked image, it is close to the sRGB gamut boundry for yellows. As a worked image, it is easy to blow the yellow gamut out to require a wide gamut space, even beyond Adobe RGB. This is before dedicated saturation boosting is performed, just simple toning pushes the yellow gamut beyond Adobe RGB.

But the image is not pure yellow. The L and A channels also have a major impaact on the conversion in the detailed areas of the orange feathers (as I have been commenting on a non detailed area of higher saturation). You may be surprised at print results when comparing the various methods (keeping in mind that preparing this for TR001 is different than for wide gamut inkjet and that either may be the hypothetical task).

Best,

Stephen Marsh.

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Bob Frost"

Mon Nov 20, 2006 8:28 am (PST)

Murray,

Mmmm! As we ourselves are mere creatures of 'nature', surely anything we do or make must be 'natural'? ;)

Clearly, what we need is an ultra-ultra-ultra-wide space big enough to hold infra-red and ultraviolet colors - all perfectly natural!

"Color space - the final frontier. To boldly go where no man has gone before." Or something like that.

This coffee seems a bit strong today!

Bob Frost.

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Lee Clawson"

Mon Nov 20, 2006 8:29 am (PST)

on 11/19/06 9:45 PM, Ric Cohn wrote:

Just because the blade is sharper doesn't *necessarily* mean it's

more likely to injure an experienced and careful worker. On the other

hand, a power saw with it's safety guard removed is inherently

dangerous and a good tool used for the wrong purpose can ruin a job.

So, which is it? I don't think anyone is arguing that ProPhotoRGB is

never a suitable choice so I see two reasonable arguments to be made:

1). More advanced, but suitable for every use, or 2). A sometime

tool (with the when and how much still TBD). Other's may see other

choices as well.

Andrew's given his view. What do other's say?

Ric,

I don't use it as my normal working space. Andrew has been asking something akin to this for 2 years. After reading, "why not go with one that will always have the gamut to contain the image?" I did say that that mades sense to me.

Your worries about all the ways I (we) can indeed make a mess of things makes sense too, but they hold true for everything else I do (especially with my inability to properly address e-mails). And the unrelenting processing overhead has been with me since we started working with hi-res drum scans.

Lee Clawson

2/\V/\7 Studio

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Lee Varis"

Mon Nov 20, 2006 10:22 am (PST)

On Nov 19, 2006, at 5:45 PM, Ric Cohn wrote:

Take away the argument for not working totally in 16 bit (or perhaps

for not working on ProPhotoRGB files in 8 bit), do other's see a

disadvantage to working in such a huge space (particularly when I

normally work with relatively subtle colors and corrections)?

You know, I just got through a long post about how I'd prefer to work in a colorspace where I can "SEE" all the colors I'm dealing with... apparently this important consideration is missing from the discussion yet again. If you regularly use ProPhoto you run the risk of adjusting colors outside of the gamut of your monitor – these are adjustment that you CANNOT see... are you comfortable doing that? If so, by all means have at it but lets make sure we remind people that THAT guarantees you are going to end up with some surprises from time to time when you go to print!

I'd rather save ProPhoto for those rare times when I know I'm going to be working with extremely saturated colors that are IMPORTANT to the image. Every example we've seen so far indicates that this is going to be a fairly narrow range of images and users should be cautioned against adopting a default that only benefits a small percentage of images while possibly causing problems for the majority of images you would likely be making adjustments for! SO I'd have to go with number two:

I don't think anyone is arguing that ProPhotoRGB is

never a suitable choice so I see two reasonable arguments to be made:

1). More advanced, but suitable for every use, or 2). A sometime

tool (with the when and how much still TBD). Other's may see other

choices as well.

regards,

Lee Varis

President, LADIG

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Andrew Rodney"

Mon Nov 20, 2006 11:12 am (PST)

On 11/20/06 8:47 AM, "Lee Varis" wrote:

You know, I just got through a long post about how I'd prefer to work

in a colorspace where I can "SEE" all the colors I'm dealing with...

apparently this important consideration is missing from the

discussion yet again.

That's fine and doable as long as you don't care about the colors you can see and reproduce on print.

If your final output is a display, you should work in a reduced gamut space.

If your final output is to a print AND that device exceeds sRGB (which is real easy to find), then you have to decide what's more important: seeing the colors and not getting them on output or not seeing the extreme colors and getting them on output to print.

This isn't at all complicated.

You could flip for an extended gamut display as well (besides the cost, there are some issues with this technology).

Display technology today is no doubt the weakest link in all of the tools we have in digital imaging but that's changing (slowly). At PhotoPlus I saw a Samsung Wide Gamut display (it exceeds Adobe RGB (1998)) that allows one to switch the chromaticity output to sRGB when necessary due to the use of LEDs for the backlight. Best of all, it had a MSRP of less than $2000! Soon Lee, you can see more and output more without breaking the bank. Of course in the meantime you can funnel all your precious images into sRGB. I wouldn't recommend it.

If you regularly use ProPhoto you run the risk

of adjusting colors outside of the gamut of your monitor

Substitute any color space larger than sRGB into the above sentence if you don't have an extended gamut display.

these are adjustment that you CANNOT see... are you comfortable doing that?

Absolutely because I can see them when I output the file. That's my final, a print. To a very wide gamut device that exceeds Adobe RGB (1998).

If so, by all means have at it but lets make sure we remind people that

THAT guarantees you are going to end up with some surprises from time

to time when you go to print!

There's always going to be some surprise until soft proofing is 100% which I submit will never happen. Did your output to any reflective media match your transparency? Nope. You've got two radically different reference medias. A reflective print will never match an emissive display or a backlit chrome.

I'd rather save ProPhoto for those rare times when I know I'm going

to be working with extremely saturated colors that are IMPORTANT to

the image.

Why guess? Has anyone come up with an image in ProPhoto RGB in 16-bit that provides any disadvantage to a smaller space upon output? I'm still looking for one. I HAVE provided to the list an image that falls apart in any space BUT ProPhoto. I'm looking for the opposite raw file. You have one?

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Terry Wyse"

Mon Nov 20, 2006 1:46 pm (PST)

I think this should be qualified somewhat. Just because there are colors outside your display's color gamut doesn't NECESSARILY mean that these colors will get clipped and render to the display with no detail. There's at least two monitor profiling packages that I can think of that offer a tunable "gamut compression" feature that can bring OoG colors into the display gamut. It's sort of a perceptual rendering as colors get near to the edge of the display gamut. The color won't be 100% ACCURATE at that point but it's not as though your editing these OoG colors totally blind either.

Regards,

Terry Wyse

_____________________________

WyseConsul

Color Management Consulting

G7 Certified Expert

704.843.0858

http://www.wyseconsul.com

http://www.colormanagementgroup.com

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Mon Nov 20, 2006 1:47 pm (PST)

On Nov 20, 2006, at 10:47 AM, Lee Varis wrote:

You know, I just got through a long post about how I'd prefer to work

in a colorspace where I can "SEE" all the colors I'm dealing with...

Terrific post BTW! I agree with almost everything in it. However, I'm not sure this one point is actually practical. Since no color space matches both my monitor and my printing space, I've always worked with one eye on my info pallet, even with sRGB or ColorMatchRGB. Using just my monitor view, it's too easy to be seduced by images that look good to my (adapted) eyes, but print badly (blown highlights, plugged shadows, too weak or flat colors, etc.). To me, this is much like my old film days where I would use a polaroid to preview my images. Years of experience helped me to interpret what I saw and an understanding of Polaroid's weaknesses helped me to know when not to go by it's "preview". I'm really looking for reasons that using ProPhotoRGB will lead to lower quality even if I don't exceed my printer's gamut. For example, is it harder to work with skin tones and near neutrals? Do subtle color's turn out flatter? Is it harder to convert the files to my output space? In other words, is using ProPhotoRGB for my normal Inkjet output really more dangerous than using AdobeRGB? I don't know. I actually suspect some of this is true and I will certainly not move to ProPhotoRGB unless I should somehow become completely convinced that I am wrong.

I'm also coming (late) to the conclusion that looking at the Output Preview for my Inkjet print profiles is as important as looking at my traditional CMYK preview. In looking at the example images that have been posted, my Proof Setup does a surprisingly good job of showing the same relative color changes I see in the prints. Yes, I do think it's ironic when Photographer's who go totally by their monitor's preview insist on using color spaces that don't show the colors they will get.

...users should be

cautioned against adopting a default that only benefits a small

percentage of images while possibly causing problems for the majority

of images you would likely be making adjustments for! SO I'd have to

go with number two:

What I'm trying to understand is what (besides an increased chance of creating OOG colors) the problems it causes are. From what I know, I'd say using ProPhotoRGB does not make sense for my normal commercial work. First there is the 16 bit issue. It does appear that you need to work in 16 bit ProPhotoRGB if you want to maintain maximum quality-- and why use ProPhotoRGB unless that's what you're trying to get. Second, IMO, ProPhotoRGB use requires more care to avoid OOG problems. For perhaps 90% of my images the most important usage is traditional CMYK use, and the largest second usage would be the web where ProPhotoRGB is an even more ridiculous choice.

However, what about my personal and portfolio work? Here I'm always spending significant time getting an image how I want it and my main use is output to top quality inkjet printers. What are the disadvantages over AdobeRGB? I think knowing if and what the disadvantages are would be helpful in evaluating working space choices. If it's just a matter of learning what to avoid then I might put up with these "dangers". After all, Curves is probably the most powerful and the most dangerous of all Photoshop commands for the uneducated or sloppy, but no one here would argue against using them. If there are other inherent dangers to *any* working space then perhaps another color space besides AdobeRGB would be better for the vast majority of my images-- whether that space is larger or smaller or just different.

Ric Cohn

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "John Denniston"

Mon Nov 20, 2006 1:48 pm (PST)

At 11:40 AM 11/20/2006 -0700, Andrew Rodney wrote:

you have to decide what's more important: seeing

the colors and not getting them on output or not seeing the extreme colors

and getting them on output to print.

There's always going to be some surprise until soft proofing is 100% which I

submit will never happen.

A reflective print will never match an emissive display or a backlit chrome.

Hi Andrew,

I take it from these quotes that your advice to people is to do colour correction by the numbers and not by what they can see on the monitor?

Regards,

John Denniston

www.dennistonphoto.com

www.dirtbikephoto.com

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Terry Wyse"

Mon Nov 20, 2006 4:27 pm (PST)

On Nov 20, 2006, at 4:16 PM, John Denniston wrote:

Hi Andrew,

I take it from these quotes that your advice to people is to do colour

correction by the numbers and not by what they can see on the monitor?

I'm not Andrew of course but I'd like to comment. I'd say unless your output is very focused on specific kinds of output, say SWOP and/or offset CMYK, I think color-correcting by the numbers would be very challenging these days if you're editing in the final output color space. With today's wide-gamut inkjet printers in combination with various proof/photo print RIPs, you could have WILDLY different numbers that would produce the same output color. Unless you knew intimately how that printer prints (or you referenced Lab or soft-proof CMYK values in your info palette), memory colors such as fleshtones would be darn near impossible to correct "by the numbers". You couldn't even count on, say, an Epson 4800 giving you the same CMYK values through a RIP due to the variable of calibration/linearization.

Later,

Terry Wyse

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WyseConsul

Color Management Consulting

G7 Certified Expert

704.843.0858

http://www.wyseconsul.com

http://www.colormanagementgroup.com

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Murray DeJager"

Mon Nov 20, 2006 4:28 pm (PST)

Hi Bob,

Mmmm! As we ourselves are mere creatures of 'nature', surely

anything we do or make must be 'natural'? ;)

I knew I was going to get caught with that statement. Most nature photographers, I think, do their best to remove any signs of man from their shots. So, for example, if they were taking a photograph of a clump of aspen trees in the fall they would probably remove the brightly colored piece of art paper that somebody threw out from the scene. :)

Clearly, what we need is an ultra-ultra-ultra-wide space big enough to hold

infra-red and ultraviolet colors - all perfectly natural!

Don't forget about the x-rays...

"Color space - the final frontier. To boldly go where no man has

gone before." Or something like that.

This coffee seems a bit strong today!

Never mind how strong it is... the important question is, what color is it? Or maybe more importantly, What color do you interprete it to be?

Murray DeJager

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Andrew Rodney"

Mon Nov 20, 2006 4:49 pm (PST)

On 11/20/06 2:16 PM, "John Denniston" wrote:

Hi Andrew,

I take it from these quotes that your advice to people is to do colour

correction by the numbers and not by what they can see on the monitor?

I recommend both. But there will never be a 100% match between the two diverse medias that's simply impossible. And only some numbers are at all useful (what's the correct neutral value for output to an Epson 3800 on matt paper?). The ICC profile will tell us this anyway.

I agree with Ric about having to do a mental transform in your head as we photographers had to do for years with Polaroids. A good soft proof is vastly closer so the mental transform is pretty tiny in comparison.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Matthew Rigdon"

Mon Nov 20, 2006 5:16 pm (PST)

On Nov 20, 2006, at 7:47 AM, Lee Varis wrote:

You know, I just got through a long post about how I'd prefer to work

in a colorspace where I can "SEE" all the colors I'm dealing with...

apparently this important consideration is missing from the

discussion yet again.

Some of this goes back to one of the goals of color management, which was to allow you to see what you were going to print. Now you can SORTA see what you're going to print, but not completely. But maybe it should be pointed out that if you don't want to make multiple prints with your inkjet, you may really be better off picking a narrower color space than ProPhoto and buying a monitor with the widest gamut possible, which pretty much leaves Adobe RGB the best option. I don't believe there are any monitors out there (yet) that can exceed Adobe RGB by any appreciable margin.

The cost of inkjets has come down, so the problem of test prints isn't about money, but it is still about TIME. I would have to say, absent any scientific breakthroughs that allow us to counter the effects of gravity and friction, inkjets won't be getting appreciably faster. You can only throw that little printhead around so fast before it starts burning up gears, throwing the head out of alignment, creating enough angular momentum to wreak havoc on local weather patterns ;)

If you make only one or two prints a day and you get a lot of money for them, it's worth the time to use ProPhoto and do test prints. Otherwise, you may be better served staying within the limits of your monitor's soft proofing capabilities.

The other question is how quickly can we expect monitors to improve. Right now, the big seller for LCDs is HD tv sets, and NTSC and even HD don't require a very large color gamut. There's not a huge incentive to build a wide-gamut monitor (a lot of video professionals lament the fact now that they can't get really high-quality LCD preview monitors for production work. Since CRT disappeared, you're stuck in a world where you can't ever see everything you shoot on a monitor). There are always promises of new-fangled technologies that will show marked improvement over LCD, but how long will it take those to get to market?

I've never heard Dan say this, but I do believe that his writings indicate that he feels a professional should be able to get a great looking print no matter what color space is chosen. A real professional in any field should be able to work within whatever limitations exist and actually produce a competitive, if not superior result, to someone working with better equipment but less skill.

Matthew Rigdon

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Murray DeJager"

Mon Nov 20, 2006 5:28 pm (PST)

Hi Richard,

If all you ever send to the printer are numbers appropriate for a

display, the printer will never show you what it is capable of

printing.

But I assume that if all the numbers in the scene fit within the numbers of a display then it's okay to send those numbers to the printer? I hope the objective of photography never becomes to print the maximum colors the printer is capable of printing all the time.

In many ways, photographers have been stuck with the 12-pack of

Crayons, instead of the 250-pack that oil/watercolor/acrylic

artists have had. What many haven't realized is that they've had

a 50-pack all along, but they've only been using 12 crayons out of

the pack, and a 100-pack was right under their nose.

If the 12-pack of Crayons includes all but the very brightest of colors that may exist then maybe for all but a few photographers that's fine.

A few photographers have not been satisfied with even the 100-pack

of crayons, and they've pushed the envelope.

I don't think anybody's would claim that's wrong.

My friend Marco Ugolini recently reminded me of Bill Atkinson's

work. Every color that can be perceived in the mind's eye is a

color of nature, and Atkinson' s images show colors that are nearly

surreal. If you've never seen his work, spend 5 minutes here

(realizing that the colors are limited to the gamut of your

display!): http://www.billatkinson.com.

I did visit the site and I like his work. But I have a question, and I'm sincere about this. I'll admit that there are colors in his prints that I might not be able to see on my monitor. But an interesting thought just occured to me. What compensating effect does looking at a photo through an sRGB monitor have, as compared to looking at a Prophoto photo with more intense colors but viewed on a paper substrate? I ask that question because I think I would appreciate Bill's final visions more in print because I think maybe the monitor adds too much brightness to the colors. Just a thought.

The colors of nature are limited only by what your eyes can see

and your brain can perceive.

I'm not a color scientist so I could be wrong. But to me it sounds better to say: The colors your eyes can see are limited only by what's found in nature. From an evolutionary perspective that would seem to make more sense. Dan made a comment in his LAB book that went something like: 'Can you conceive of a yellow so colorful and yet totally black... LAB can.' Forgive me if I didn't quote that exactly.

As John described, it's

his job to reproduce the artist's vision to the best of his abilities.

When reproducing existing art absolutely. But you make it sound like every artist out there uses a palette of colors that far exceeds the gamut of the average photograph. Some do, but again just looking around at the limited collection of art my wife has collected over the years I would, bravely, suggest that most artists stay well within the gamut of sRGB. My first wife was also an watercolor artist and I don't think intense colors are even possible in that medium.

Lastly, I hope this exercise has allowed some on this list to

realize that there can be a lot more color information in an image

than what is seen on a display, and that it is possible to print

this information on an inkjet printer. Images with bright colors

like oranges benefit, as do images with deep greens and rich blues

and purples.

The only question in dispute was how often those colors present themselves and if using a color space like Prophoto all the time to capture them was wise.

Like many of you, I distribute most images to clients as 8-bit,

aRGB TIFs, unless they request otherwise (16-bit, or CMYK, etc.)

or unless there's a good reason to give them something else based

on their intended use.

Bravo! You're learning. :)

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "John Denniston"

Mon Nov 20, 2006 10:10 pm (PST)

Hi Terry,

Adding your comments onto what Andrew has said I would have conclude that it is impossible to colour correct with any accuracy a wide gamut image printed to a wide gamut inkjet printer.

Can't be done by the numbers because different numbers produce the same colours. Your comment.

Can't correct by referencing the monitor because the colours are out of the monitor's gamut. Andrew's comment.

Can't correct by the softproof because it isn't, and never will be accurate. Andrew's comment.

Andrew, agreeing with Ric Cohn, says to do a "mental transform in your head"

This is colour management? Sounds like Photoshop 4 to me.

Regards,

John Denniston

www.dennistonphoto.com

www.dirtbikephoto.com

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Andrew Rodney"

Mon Nov 20, 2006 10:12 pm (PST)

On 11/20/06 5:37 PM, "Matthew Rigdon" wrote:

The cost of inkjets has come down, so the problem of test prints

isn't about money, but it is still about TIME. I would have to say,

absent any scientific breakthroughs that allow us to counter the

effects of gravity and friction, inkjets won't be getting appreciably

faster.

You think? Cause that©ˆs not what we©ˆve seen over the past few years. My Epson 3800 is quite a bit faster than a 4800. My Epson 2400 is much faster than my 2200 and the Epson 2000P was dog slow in comparison. That©ˆs only about 4-5 years max in terms of ink jet technology. I would submit that the speeds we see in ink jet is far more reliable compared to countering the effects of gravity and friction.

The time today for me to crank out an 8x10 on a 3800 is a lot faster than what it took to print an 8x10 on my first dye sub printer. The gamut and quality is much better too.

The other question is how quickly can we expect monitors to improve.

Not fast enough! But there©ˆ some very exciting technology coming down the pick that will make us all laugh at the current CCFL LCD©ˆs.

I've never heard Dan say this, but I do believe that his writings

indicate that he feels a professional should be able to get a great

looking print no matter what color space is chosen.

I©ˆd agree you can if you have all your ducks in order but they will not be identical and to the trained eye or those who know how to buy prints, they will see the difference. I can see it using my test flower image in ProPhoto RGB versus smaller color spaces (and if you recall, even my wife, who doesn©ˆt know a pixel from a pickle was too).

A real professional in any field should be able to work within whatever

limitations exist and actually produce a competitive, if not superior

result, to someone working with better equipment but less skill.

Agreed but a professional will strive to produce the best possible product based on the tools and techniques they have. They don©ˆt throw away data or colors because it©ˆs convenient or easier unless their back is against the wall. My opinion of a true professional is someone you can©ˆt pay to do an inferior job.

As I©ˆve said often, using just an sRGB workflow with good output profiles will not produce a poor print. But using better options like a wider gamut space IF the image and output device can support it will have a visible difference. Which would you prefer to sell?

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Tue Nov 21, 2006 6:22 am (PST)

On Nov 20, 2006, at 5:06 PM, Murray DeJager wrote:

But I assume that if all the numbers in the scene fit within the

numbers of a display then it's okay to send those numbers to the

printer? I hope the objective of photography never becomes to print

the maximum colors the printer is capable of printing all the time.

Strictly speaking, the numbers of an outdoor "scene" generally don't fit within a monitor gamut. If you mean the output-referred rendition of a scene, the goal is always to print all of those colors, regardless of what color space encloses them, if you want to faithfully print the output-referred scene.

Of course, your artistic "vision" might always make the gamut of your output-rendered image fit within your monitor gamut - that's an artistic decision (or for some, a technical decision, if they don't know how to render a wide-gamut image). You might always make your output-referred scenes in sepia, too, or high-key. Obviously, the goal is to produce the best-looking image possible and to reproduce the photographer's vision - regardless of whether the image colors are all pastels or the blues of Picasso's Blue of Barcelona. Having a capability does not imply misuse of that capability. (Printing the "maximum colors the printer is capable of printing all the time" would print an essentially black solid, but I'm sure that's not what you meant.)

If the 12-pack of Crayons includes all but the very brightest of

colors that may exist then maybe for all but a few photographers

that's fine.

If that works for you, great. Many of the additional "crayons" are not "bright" - they're also deep, saturated colors that allow holding more detail in shadows. Look at the gamut maps - it's not just at high L* that the gamut of ProPhoto (or printer profiles) exceed sRGB - it's often at mid-low L*.

If you're always happy with your output from sRGB or whatever you use, great. For your "vision" it may be perfectly adequate. Most photographers want larger gamuts from their inkjet printers, although many do not realize that they are limiting the gamut of their printers by their choice of working space, especially if that choice is sRGB. "I bought an expensive new printer but the prints look the same." Yea? What's the gamut of the image? If it's less than the gamut of the old printer, you won't see an increased gamut, because the gamut of the printer was not a limiting factor. My example image would clearly show this. Flat vs. vivid, simply dependent on the image color space. To take advantage of the increased gamut, you have to use a wide-gamut image. Otherwise, the colors should be identical (if the profiles are good).

http://www.billatkinson.com.

I did visit the site and I like his work. But I have a question, and

I'm sincere about this. I'll admit that there are colors in his

prints that I might not be able to see on my monitor. But an

interesting thought just occured to me. What compensating effect

does looking at a photo through an sRGB monitor have, as compared to

looking at a Prophoto photo with more intense colors but viewed on a

paper substrate? I ask that question because I think I would

appreciate Bill's final visions more in print because I think maybe

the monitor adds too much brightness to the colors. Just a thought.

There is no comparison to seeing Atkinson's prints (or the printed copy of his book that used high-density inks) compared with looking at your display. Besides the difference in media (emissive vs. reflective) and size (the prints are large-format, with a ton of detail, not low-res JPGs), the prints were specifically adjusted/ corrected for print. JPGs are, well, JPGs - not really optimized for anything other than download speed. Viewing most artwork on the Web flat-out stinks compared with seeing the work in person in a gallery.

http://www.billatkinson.com/aboutTheGalleries.html

I'm not a color scientist so I could be wrong. But to me it sounds

better to say: The colors your eyes can see are limited only by

what's found in nature.

That's where your intuition and understanding of color are just wrong. Color is a quality constructed by the visual brain and it is not a property of objects that are "found in nature." Color depends on the illuminant, the view, and the visual perception system. The "colors of nature" are different to someone who is color-blind, or to animals that have something other than trichromatic vision, like bees (UV) and snakes (IR). My wording was intentional and accurate.

From an evolutionary perspective that would seem to make more sense.

Well, what you state is factually incorrect, so no need to go further, although the evolution of the visual system is a fascinating area of science.

When reproducing existing art absolutely. But you make it sound like

every artist out there uses a palette of colors that far exceeds the

gamut of the average photograph.

I didn't mean to imply that. Some use only charcoal. The hotel room I'm in right now has two original watercolor pictures hanging, by an unknown (at least to me) artist. I doubt they would have much value to a collector. One could probably be reproduced by sRGB rather easily. The second, no way. It has blues/purples just like my test image.

Some do, but again just looking

around at the limited collection of art my wife has collected over

the years I would, bravely, suggest that most artists stay well

within the gamut of sRGB.

I have no idea what your wife's tastes are in art, or whether she collects original oil paintings or reproductions (lithographs), which will obviously have a gamut limited to offset lithography.

Would artists consciously try to stay within the gamut of an emissive device originally designed for television? Why??? Is that real life?

Georgia O'Keefe sure didn't. (Again, gotta go to one of the galleries to really experience the originals.)

http://www.artst.org/okeefe

My first wife was also an watercolor

artist and I don't think intense colors are even possible in that

medium.

They are.

The only question in dispute was how often those colors present

themselves and if using a color space like Prophoto all the time to

capture them was wise.

No, many on this list feel that sRGB or display gamut is an adequate color space for printing to an inkjet printer, and the image was designed to show that it is not, if you want the full gamut of the printer to be available. Even Dan has now made it clear that he does not advocate sRGB as a working space for inkjet printing. AdobeRGB captures ~ 90% of the inkjet gamuts -that's a lot more than sRGB does, and that's why UPDIG and others recommend AdobeRGB or ProPhoto for inkjet printing. Whether anyone should go the last ~10% to ProPhoto is a question that should be determined by the needs and goals of the person doing the printing. If Bill Atkinson limited the gamut of the images in his book (or his large-format prints) to display gamut they would look pathetic in comparison.

Bravo! You're learning. :)

Every day.

--Rich Wagner

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Matthew Rigdon"

Tue Nov 21, 2006 6:27 am (PST)

On Nov 20, 2006, at 5:29 PM, Andrew Rodney wrote:

You think? Cause that©ˆs not what we©ˆve seen over the past few years. My

Epson 3800 is quite a bit faster than a 4800. My Epson 2400 is much faster

than my 2200 and the Epson 2000P was dog slow in comparison. That©ˆs only

about 4-5 years max in terms of ink jet technology. I would submit that the

speeds we see in ink jet is far more reliable compared to countering the

effects of gravity and friction.

Let's take Canon as the gold standard of inkjet speed printing. Yes, Epson has made a lot of improvements, but I don't believe they've caught up to Canon yet and Canon's print speeds aren't accelerating very much these days. You can eek a little more speed out of the Epsons, but I would be inclined to think that Canon is a little like the Lamborghini of printers, showing us about where we're going to run out of horsepower. It's fast, but not 4-color press fast. Or monitor fast My monitor is pretty much instantaneous. I mean, as far as my eyes can tell ;)

Agreed but a professional will strive to produce the best possible product

based on the tools and techniques they have. They don©ˆt throw away data or

colors because it©ˆs convenient or easier unless their back is against the

wall. My opinion of a true professional is someone you can©ˆt pay to do an

inferior job.

Ah, but out here in the real world, we're subject to the holy trinity of budgeting choice intersected with the law of twos: High Quality, High Speed, Low cost, pick two. :)

And there are lots of people who are going to send their work straight into a catalog or onto a postcard, so what do you have to gain by taking on an ultra gamut workflow when you KNOW all that work is going to be thrown out at the end. In the off chance that one day, something you slipped into an office supply catalog will be considered art, you can always go back to your RAW file and re-edit for a fine art print. although, oddly enough, someone might want it in its original CMYK glory to hang on the wall. People can be weird that way.

As I©ˆve said often, using just an sRGB workflow with good output profiles

will not produce a poor print. But using better options like a wider gamut

space IF the image and output device can support it will have a visible

difference. Which would you prefer to sell?

If I'm not able to command a high price, just because I don't have a "reputation", then I prefer to sell what I can do profitably. You obviously have to balance your time according to all the other things that life throws at you. In the art world, a "reputation" will do more for the price you can charge than the way in which you print. I'm not saying you shouldn't strive to make the best prints, but spending many hours and lots of money to make less than minimum wage on your art is a sure way to guarantee that your work will only be profitable when you're dead.

Matthew Rigdon

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Handling OOG Colors (was RGB Working Space)

Posted by: Dan Margulis

Tue Nov 21, 2006 6:22 am (PST)

Bill Theis writes,

In spite of all these attempted safeguards, I am unfortunately still guilty

of driving out of gamut colors in my images as many appear "cartoonish" to

some extent.

This is one of the biggest problems facing a lot of people today. I see this effect all the time in my classes and at shows, and instructions on how to prevent it was one of the biggest reader requests for the new edition. It happens most commonly when going from RGB to CMYK but as you have discovered it also happens in better printing conditions.

It has become more prevalent in the age of digital photography because most acquisition algorithms shortchange highlight values, which are critical in retaining detail in brightly colored areas. Overall, digicams exceed the performance of film cameras but they do not approach film quality in such brilliant areas or in deep shadows.

It is disconcerting that the "Gamut Warning" for the monitor is not a good

indicator that I have gotten into trouble. So the only thing to do is to

look for loss of detail in the AdobeRGB98 channels? Or is there a better way to check for problems from the point of view of the printer and it's colorspace?

You need to keep an eye on channel structure throughout the process as that is the key to retaining detail in the bright areas. These detail-free areas can come about if you call for a color that's beyond the printer's ability to produce; much more rarely (though you seem to have done it) they happen because you've gone beyond the capability of the colorspace as, for example, by going so far in LAB that Adobe RGB can't hold it.

However, in brilliant areas, the problem starts with the camera. Sometimes the colors are so intense that they simply overpower the camera and result in blobs of color, but even if the camera technically is capable of recording them the result is usually too colorful.

When we're confronted with large bright areas, for simultaneous-contrast reasons humans see a more rapid falloff from the brightest area than the camera does. So, in either of the two yellow flowers I tested, especially the brighter one, correction would be needed to achieve a properly detailed result. The yellowest parts need to stay as yellow as they can, but the process of desaturation outside those areas needs to be accelerated--the camera keeps them too yellow too long.

Some type of channel blend is usually needed to retain this detail. Often I acquire the picture in ProPhoto because its channel structure is the best-defined for this type of blend. Then, I take a copy into LAB and blend one of the ProPhoto channels, usually the lightest one, into the L for added detail. At that point I can start to increase saturation if needed.

The biggest way to keep things under control is to be conservative with the *preliminary* move. If you have decided to increase saturation in LAB but output in Adobe RGB you're in the same position as someone who decides to increase it in Adobe RGB but needs to output in CMYK. Both are dangerous practices unless handled conservatively. You don't win a prize for achieving perfection with your first attempt--you get a second try in the output space.

So, don't increase saturation to the point that you're certain that detail is held. Then, when you make the final conversion to CMYK or to your RGB output space, go to the lightest channel, find the lightest point, and blow it out. IOW, if the object is brilliant red, somewhere in the cyan/red channel there needs to be a blank area, but it can't be so big that the viewer will perceive a blob. This way, you get a smooth transition into the less colorful areas.

Dan Margulis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Andre Dumas

Tue Nov 21, 2006 6:27 am (PST)

Good morning Richard,

Much of what you and Andrew say about wide gamut spaces is, as far as I can see, irrefutable. Thanks for the link to Atkinson's images, It looks like most are OoG for sRGB. Watch out for those mating rattlesnakes.

Richard, I'm a, sometime, oil (and acrylic) painter, I've seen artists with more than 50 tubes of paint and I've read books where the author suggests palettes using 10 different reds, 5 different blues, 8 greens, 5 yellows, etc., and yet I don't think that there are many paintings that I cannot reproduce with 3 warm primaries and 3 cold primaries, six tubes of paint! Have a look at Michael Wilcox's book "Blue and Yellow don't make Green".

So, ProPhoto's gamut is much larger than sRGB's but in my photography of landscapes and even with my highly saturated close-ups of flowers I don't think that it matters much. Even when I do a side by side comparison of prints, they both look good, one is more striking the other is more subtle.

It's amazing what sRGB can do!

André Dumas

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: "mrmrking"

Tue Nov 21, 2006 9:25 am (PST)

Dan wrote

However, in brilliant areas, the problem starts with the

camera. Sometimes the colors are so intense that they simply

overpower the camera and result in blobs of color, but even if the

camera technically is capable of recording them the result is usually

too colorful.

I have this problem with some autumnal shots on my D2X where the sun lit yellow and orange leaves are even OOG for Prophoto and JS' DCAM 5. I would like to see where the camera thinks these colours lay. Is there a bigger space than ProPhoto I can use to visualise these (using Colorthink)? It needs to be an RGB working space so that Nikon Capture will convert into it. I want to see, for example, if they are even visible colours.

Mike King

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: "Iliah Borg"

Tue Nov 21, 2006 10:34 am (PST)

Dear Mike,

Please make a NEF available. We will see what colours are recorded by camera, and what are the faults at the stage of the conversion from raw. Those are two distinctly different problems. The idea to judge camera colour capabilities by the output of a raw converter is even worse then to judge them by out of camera JPGs.

Best regards,

Iliah Borg

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: "williamtheis"

Tue Nov 21, 2006 10:39 am (PST)

Dan Margulis wrote:

When we're confronted with large bright areas, for simultaneous-contrast

reasons humans see a more rapid falloff from the brightest area than

the camera does. So, in either of the two yellow flowers I tested,

especially the brighter one, correction would be needed to achieve a

properly detailed result. The yellowest parts need to stay as yellow

as they can, but the process of desaturation outside those areas needs

to be accelerated--the camera keeps them too yellow too long.

this seems to be the basis of the saturation mask in another thread. I will take a careful look at all you have said. But this begs the question: is there any utility at all for the Photoshop gamut warning? or is it just too crude for critical work that would better be done by continuously monitoring the lightest parts of the channels for details?

Bill Theis

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: Andre Dumas

Tue Nov 21, 2006 2:00 pm (PST)

Hello Iliah,

You said

The idea to judge camera colour capabilities by the output

of a raw converter is even worse then to judge them by out of camera

JPGs.

This is *very* interesting! Would you tell me more about it? I thinkyou said you were involved in the creation (?) of a raw converter, is it available and where can I buy it?

Is that you sleeping on that picnic table?

André Dumas

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: "Iliah Borg"

Tue Nov 21, 2006 4:55 pm (PST)

Dear André,

Raw converter applies the "best guess" colour mapping. It is up to third-party folks to make that guess, especially when it comes to chromaticity of dyes used in CFA filters.

JPGs, at least Nikon's JPGs as the camera in question is Nikon, are based on real spectrophotometric data.

Next, if you look inside ACR they use a kind of matrix transform from what they guess is the camera "colour space" to their internal working colour space (which happens to have ProPhoto gamut). Is the use of ProPhoto here justified by anything but the theoretical concept that it for sure can embed any visible colours the camera can capture?

Last, we have Opensource tools to see those RGB/greyscale numbers as they were recorded by the camera. So we want to answer Mr. King's question "I would like to see where the camera thinks these colours lay" we need to turn to raw data, not to renditions of it.

Converter we wrote is RAWMagick Lite.

Best regards,

Iliah Borg

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Tue Nov 21, 2006 9:31 am (PST)

On 11/20/06 6:37 PM, "John Denniston" wrote:

Can't correct by referencing the monitor because the colours are out of the

monitor's gamut. Andrew's comment.

Can't correct by the softproof because it isn't, and never will be

accurate. Andrew's comment.

Andrew, agreeing with Ric Cohn, says to do a "mental transform in your head"

Forgive me for saying this but you're making a mountain out of a molehill!

First, the colors you can't see are going to be at the extreme edges of the gamut outside the display contained within the image. It's not like the entire soft proof falls apart. Its not like there©ˆs an awful color shift. Some saturated colors don't look as saturated. You CAN handle this by using either one of the software packages that allow compression within the display profile (Monaco OPTIX as an example), you can use the Desaturate By command in the color settings (a kludge compared to the above) you can get a wider gamut display. Don't throw the baby out with the bath water here.

A contract proof has never matched a press sheet 100% that I've ever seen. Pretty close. A transparency has never matched any reflective output on the planet. That didn't stop people from using the tools to match dissimilar media with some idea of what they'll get on output for years!

Or you could be so concerned about some colors, colors you can't define or could take the time to define for all images and funnel colors into sRGB to accommodate a very dated display technology and then you'd STILL have a dissimilar reference media to handle (emissive versus reflective). Don't forget that sRGB is based on a very old, CRT display technology circa 1993 of which few if any such devices are still in existence. I'll add that LCD displays don't behave like sRGB devices by a long shot anyway.

Meanwhile, the LCD vendors try to sell you on displays with increasing larger contrast ratios while the output contrast ratio isn't changing and it's smaller than any LCD you can buy. At least we are starting to see affordable wide gamut LCD's backlit with something other than a $2 Fluorescent light bulb!

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Murray DeJager"

Tue Nov 21, 2006 2:03 pm (PST)

Hi Everyone,

One final (I hope) comment on this thread... I'm confused.

Once again it seems to boil down to two really different camps. One camp, that includes Dan, says that there are no real colors in nature (definition varies on whats natural) that sRGB can't handle 99.99% of the time. And then there's the other camp that says not only do these colors exist but they're damn near everywhere and not even aRGB is a wide enough space to contain them!

So maybe the only solution is to outfit everyone on this list with a spectrophotometer and have them take actual samples of the colors in their world.

I have to say, however, that I'd probable skew the results because I live in Canada... and it's winter! The most colorful thing I've seen lately is a Coke can sticking out of a snow drift!

Murray DeJager

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Bob Frost"

Tue Nov 21, 2006 4:59 pm (PST)

Murray,

You've done it again! Which space is needed to encompass Coca Cola red? :)

Bob Frost.

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Tue Nov 21, 2006 5:00 pm (PST)

On 11/21/06 1:35 PM, "Murray DeJager" wrote:

Once again it seems to boil down to two really different camps. One

camp, that includes Dan, says that there are no real colors in

nature (definition varies on whats natural) that sRGB can't handle

99.99% of the time.

I don©ˆt know he said that but it©ˆs absolutely a ridiculous statement. For one, how do you define ©¯colors in nature©˜? What's a real color (one I can see I'd hope). If we can see seem, if they fall within human gamut, that©ˆs one thing. I can©ˆt see X-Rays or gamma rays so I don©ˆt care to define them within the context of what can be captured and output using the technology discussed on this list. But all you have to do is look at the gamut plot of human vision (the CIE chromaticity diagram) and sRGB to see there©ˆs a huge number of colors outside sRGB we can see. Next you can plot the gamut of all kinds of output devices and again see, many (even SWOP) contains colors that fall outside that space. Lastly, you can look at the clipping indicators in a decent RAW converter to evaluate colors the capture device captured that fall outside sRGB. So where©ˆs the confusion? The math is undeniable!

So maybe the only solution is to outfit everyone on this list with a

spectrophotometer and have them take actual samples of the colors in

their world.

It©ˆs not that difficult or expensive to prove the above points. If you have Adobe Camera Raw, you can plot capture gamut within the four most common RGB working spaces. If you have something like ColorThink, you can plot the rendered image and any ICC profile in respect to human gamut. There are even a few free gamut mapping utilities that will allow you to do this san©ˆs importing an image.

I have to say, however, that I'd probable skew the results because I

live in Canada... and it's winter! The most colorful thing I've seen

lately is a Coke can sticking out of a snow drift!

It probably falls outside sRGB gamut. That can has some red in it right?

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Terry Wyse"

Tue Nov 21, 2006 5:01 pm (PST)

On Nov 21, 2006, at 3:35 PM, Murray DeJager wrote:

So maybe the only solution is to outfit everyone on this list with a

spectrophotometer and have them take actual samples of the colors in

their world.

Better yet, I had LASEK surgery done a while back and had the optional spectrophotometer-to-optic nerve interface added. I even went with the UV and IR nanometer band extension. I can't wait until I can go to the beach and see through all those bathing suits! (well, SOME of them anyway). You talk about the Color of Nature!

Regards,

Terry "L*a*b* vision" Wyse

...and yes I'm kidding. Just trying to add a touch of humor.

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Dan Margulis

Tue Nov 21, 2006 6:33 pm (PST)

Lee Varis writes,

I'd rather save ProPhoto for those rare times when I know I'm going

to be working with extremely saturated colors that are IMPORTANT to

the image. Every example we've seen so far indicates that this is

going to be a fairly narrow range of images and users should be

cautioned against adopting a default that only benefits a small

percentage of images while possibly causing problems for the majority

of images you would likely be making adjustments for!

and Rich Wagner writes,

Most images print fine from aRGB, as was noted by David Cardinal and

John Castronovo, but it is useful to keep an eye out for those that

would do better in a wider gamut color space, as was noted by John.

We've decided that it's worthwhile to use 16-bit ProPhoto as an

output conversion/archiving space, and we haven't run into the feared

ProPhoto boogeyman.

Well, well, well. For all the noise, it seems that there's basic agreement. Nobody seems to question using ProPhoto as an archiving or conversion space; nobody seems to question that the images that might *require* its use are few and far between; and everybody seems to suggest that these exceptional images can be recognized and diverted to an ultra-wide RGB if that's what seems appropriate. All very sensible, and if we leave it at that, everybody should be happy.

Unfortunately, instead of stopping there, some have advocated using ProPhoto as a general *working* space--that is, making edits, sometimes substantial, in it, for *all* RGB files, not just the handful that require it. This is a really good way to hose images, which is why the idea has been obsolete for 15 years or so, and is still adopted only by a tiny minority. As an editing space it has no advantages at all, and carries a lot of baggage.

Before even considering such perpetrating such an atrocity on their defenseless images, members should ponder the three examples they've seen so far. For reasons discussed previously, a natural image that requires ProPhoto virtually has to be something brilliantly yellow with detail, like the flower image by Vladimir Yelisseev.

As for the images submitted by our two resident evangelists, Andrew's didn't even need Adobe RGB, let alone ProPhoto. Rich's probably does want ProPhoto, but there's a small catch. When the rest of us work on photographs, they normally come out in some form that the viewer would recognize *as* a photograph. Furthermore, the viewer usually can hazard a guess as to what the photograph might be a photograph *of*. Rich's fails on both counts. The only reason we think it's a photograph is that he says it is, and a viewer could guess for a thousand years before divining what its subject was.

Me, I've processed nearly 100,000 images since the last edition of Professional Photoshop, and I've been specifically looking for examples that show RGB gamut problems. Vladimir's is the only image I've seen in that time that I consider might actually present a problem if worked in Adobe RGB. I haven't seen the fine art images cited by John Castronovo, but they might qualify also. I discount Rich's image as too atypical, but in any of these cases the course is clear--open the image in ProPhoto and, if LAB is not an option, work on it there. Whether they *actually* need a space that wide is unimportant--if we *suspect* that they might that should be enough to provoke us to avoid Adobe RGB.

Your mileage may vary, but it's really hard to imagine a justification for crippling one's workflow generally to cope with exceptions that come along as infrequently as we've seen.

Dan Margulis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Terry Wyse"

Tue Nov 21, 2006 6:36 pm (PST)

I don't mean to prolong this discussion but this is where I need "help".

On one hand I keep hearing that digicams, particularly those that produce RAW files, don't really HAVE a color gamut. The implication is that the gamut isn't defined until it's rendered to a color space. I can kind of accept that, to a point (I would say, like a scanner, that a digicam sensor still has a finite dynamic range but I'm not smart enough to know if that can be equated to a "color gamut". My gut sez yes it can.).

But then I get statements like the above that seem to counter that this. If the digicam doesn't have a color gamut until it's rendered to a RGB working space, how do I know if that's an accurate interpretation of the "capture gamut". The argument, at least on the surface, appears to be rather circular. Just to be clear, I'm not concerned whether the capture is faithful to the scene or not, I'm simply wondering how one can speak of a "capture gamut" on one hand and then say digicams have not gamut until rendering. And if there's no way to define a capture gamut, then I'm wondering how there can be qualitative differences between digicam sensors. In the end, it has to come down to sensor dynamic range and that has to have some correlation to color gamut.

Just can't get my head wrapped around that.

Regards,

Terry Wyse

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: David Cardinal

Tue Nov 21, 2006 9:39 pm (PST)

O.K. you guys Dan's comment referred to colors that exist in nature. I

don't know where you guys live but maybe you should get out to the

country more often. Pieces of brightly colored art paper, although made

from trees, doesn't count as trees!

Murray--That seems a bit rude. My comment about the print was about the print. I didn't reference anything Dan had said or draw any conclusions other than to report on what happened when I ran the experiment Richard suggested.

To your rather awkward point about getting out in nature out of curiousity after doing Richard's experiment I went back through the reddest sand dune images I could find from Namibia and some of the orangest fall color leaf pictures I have and indeed could not find any colors that acted the same way as the construction paper.

Off to Botswana in the morning, where I'll try to make sure that we don't let the lions chew on any construction paper while we're photographing them, although the red velvet mites are amazingly saturated! --David Cardinal

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: David Cardinal

Tue Nov 21, 2006 9:39 pm (PST)

Terry--The following may be helpful. What is really happening when the camera "sees" something:

* The sensor doesn't really know anything about color or gamuts

* The individual photosites (pixels) count photons (by turning them into electrons which are measured as voltage)

* Which photons get counted are determined (mostly) by the micro-lens (think filter) that is located over each photosite

* Usually, 50% of the pixels get "green" filters, 25% "red", 25% "blue". All that means is that the wavelengths of light the filter lets through tend to be in those spectra. Once a photon has hit a pixel, though, the camera doesn't "know" anything about its wavelength, just that it was one of the wavelengths the filter was designed to pass through (or it was errant)

* There is almost always an "IR" filter to cut off wavelengths over 700nm that silicon is normally sensitive to but our eyes are not. These are not perfect, so there is a lot of "fixing" involved in making up for the fact that filter design isn't a perfect science.

* So the truly raw image is a map of photon counts combined with a (secret) response curve for of the three filter types. Those who build raw converters can either beam collimated light of every possible wavelength at the camera and determine empirically its response curve (this is what Nikon does) or shoot one or more test targets under one or more lighting conditions and then use a set of algorithms to estimate the response based on the readings from those targets under particular lighting (this is my understanding of what the ACR team does).

* The camera or the raw converter then tries to figure out what "color" was at a particular pixel from the three pixel counts, often after trying to sort out the color of light illuminating the object, etc.

* So the gamut of a D-SLR is mostly a product of the choice of the 4 filters (R, G, B, IR) along with the natural response of the silicon and the design of the sensor. E.g. you can compute the maximum color gamut the camera can potentially capture (in a single image) and differentiate if you know all the physical variables or if you measure enough.

* Products like ACR build an internal model of the camera's response to light (essentially a custom profile or two for the camera) based on their test data (from what I understand ACR uses at least two shots of test targets under different light) and then when asked to output to a particular color space they do a transform.

* One big gotcha is that photographers like their images to look good, so most raw converter authors spend time tweaking the output color--in some cases to correct for shortcomings of the sensor or the filters. So they are not necessarily designed to render some scientifically accurate image but whatever version of the image will cause the most photographers to choose to purchase their converter.

--David Cardinal

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Tue Nov 21, 2006 9:39 pm (PST)

On 11/21/06 6:27 PM, "Terry Wyse" wrote:

On one hand I keep hearing that digicams, particularly those that

produce RAW files, don't really HAVE a color gamut.

Scanners and digital cameras don©ˆt have a color gamut but rather a color mixing function. Search the lists for this, I©ˆm sure I posted about the differences a few months back.

Raw files are Grayscale data files. They simply record an amount of amplitude based on the photon©ˆs that struck the sensor. A raw converter has to produce a full color file from this data and the converter uses some pre-determined color space at some point in the process. With ACR and Lightroom this space is ProPhoto RGB using a linear gamma encoding. This space was chosen because it©ˆs so large and because the eventual gamut of this rendered file has such a potentially large gamut boundary. I believe I posted a link to one of the Lightroom podcasts with Mark Hamburg and Thomas Knoll as to why this space was selected.

The implication

is that the gamut isn't defined until it's rendered to a color space.

You the user can select an encoding color space after you render the image as you wish. In ACR you have four options ranging from small (sRGB) to large (ProPhoto RGB). Again, I©ˆm pretty sure I posted to this list how in ACR you can toggle these spaces and view the Histogram to see if you clip colors based on the current rendering of the raw data and the currently selected encoding color space.

I can kind of accept that, to a point (I would say, like a scanner,

that a digicam sensor still has a finite dynamic range but I'm not

smart enough to know if that can be equated to a "color gamut". My

gut sez yes it can.).

Again, there©ˆs no true gamut boundaries with a scanner just as there are no boundaries with a digital camera, the difference is, film (or a print) have a fixed gamut which can be defined.

But then I get statements like the above that seem to counter that

this. If the digicam doesn't have a color gamut until it's rendered

to a RGB working space, how do I know if that's an accurate

interpretation of the "capture gamut".

Sorry to sound like a broken record but again, search for my posts to the list about the differences between scene versus output referred.

The argument, at least on the

surface, appears to be rather circular. Just to be clear, I'm not

concerned whether the capture is faithful to the scene or not, I'm

simply wondering how one can speak of a "capture gamut" on one hand

and then say digicams have not gamut until rendering.

To paste what was (I believe posted earlier), In a nutshell, a color mixing function is a mathematical representation of a measured color as a function of three standard RGB primaries needed to duplicate a monochromatic observed color at its measured wavelength. Therefore, the measured pixel values don't even *get* a gamut until they're mapped into a particular RGB space. Before then, *all* colors are (by definition) possible.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Tue Nov 21, 2006 9:45 pm (PST)

On 11/21/06 6:50 PM, "Dan Margulis" wrote:

Unfortunately, instead of stopping there, some have advocated using ProPhoto

as a general *working* space--that is, making edits, sometimes substantial, in

it, for *all* RGB files, not just the handful that require it. This is a

really good way to hose images, which is why the idea has been obsolete for 15

years or so, and is still adopted only by a tiny minority. As an editing space

it has no advantages at all, and carries a lot of baggage.

You©ˆre prepared to supply a raw file that illustrates how we users can hose the files that we would not or could not with a smaller gamut space such as Adobe RGB (1998)? I keep asking, I don©ˆt hear anyone replying with such a file. What©ˆs it take to get proof?

Show me the baggage?

I keep hearing about the dangers or ProPhoto, I'm waiting to get a file that illustrates this.

There are three issues with ProPhoto RGB files of which two are true of smaller gamut working spaces such as Adobe RGB (1998):

1. You have a color gamut that exceeds the gamut of most sRGB displays (solution, a wider gamut display, a more robust display profile).

2. You really should work in 16-bit due to the large size. But considering the history of this high bit debate on this list, I'm sure Dan would suggest this isn't an issue (high bit files don't bring anything to his party, he's yet to see a case where the use of high bit files was any better than 8-bit). So we/he can dismiss issue #2?

3. It's very, very unlikely but you could in theory define colors that don't exist (colors we can't see) due to the blue primary of ProPhoto RGB falling outside human gamut. Even if you did this, you'd have to have a heck of a lot of such undefined colors that as yet I've never seen in an image from any capture device. Meaning, you'd have to go out of your way to produce something along the lines of the dreaded synthetic image or deliberately sabotage an image using only numbers to define a lot of pixels outside of human gamut in this space. Even doing so, you probably can't reproduce the colors on any device on the planet. So there's probably no real issue here.

So, we've got a pundit saying ProPhoto is dangerous and as yet, many of us are waiting for a raw file that illustrates this that we can prove ourselves. We also have a group of pundits that have shown that there are both capture devices and output devices that can't reproduce colors we can see and output without ProPhoto RGB.

And we have a series of images that illustrate that in any space BUT ProPhoto RGB, a series of Photoshop edits will produce visible image degradation no screen and in print.

Where does that leave us? Pretty clear to me until I see proof of how dangerous ProPhoto is. Show me the files!

Andrew Rodney

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Request for Retraction (was The Color of Nature)

Posted by: Dan Margulis

Tue Nov 21, 2006 1:54 pm (PST)

In a message dated 11/21/06 9:23:42 AM, Richard Wagner writes:

No, many on this list feel that sRGB or display gamut is an adequate

color space for printing to an inkjet printer, and the image was

designed to show that it is not, if you want the full gamut of the

printer to be available. Even Dan has now made it clear that he does

not advocate sRGB as a working space for inkjet printing.

OK, I've had enough.

Rich, the only person on this list who has suggested using sRGB for such a printer is yourself. You have repeatedly been advised of this, yet you continue to rail against these imaginary people who advocate it, and to suggest that I am one of them.

Only four days ago (#15572) you posted a message pretending not to understand my position, including going so far as to post the second sentence of a paragraph that I had written, deleting the first sentence that said I did not advocate sRGB. In response, #15589, I pointed out that I have *never* recommended sRGB for such a purpose and gave you several specific quotes to that effect, including a 2002 quote that said pointblank, "use Adobe RGB".

Stating opinions, even mistaken ones, is everybody's right. Continuing to state as facts things that one knows to be untrue is quite another story. Your statement "Even Dan has now made it clear that he does not advocate sRGB as a working space for inkjet printing" is plainly intended to suggest that there has been a recent change in my position.

There is no place for that type of intentional misstatement here. I therefore request that you acknowledge to the list that you do understand that I have never advocated using sRGB to those who find inkjet printing important. As for the "many on this list" who feel otherwise, if you feel that someone else on the list has advocated sRGB for inkjet printing, please name that person.

Dan Margulis

P.S. I exclude from the above anyone who is using inkjet printers solely as a proofer for eventual CMYK output, since by definition they don't wish to use the printer's full gamut, and anyone who can't control the skill level of anyone who may get their hands on the files.

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Re: Request for Retraction (was The Color of Nature)

Posted by: "Greg Welch"

Tue Nov 21, 2006 4:57 pm (PST)

Hi Dan,

As for the "many on this list" who feel otherwise, if you feel that someone else on the list has advocated sRGB for inkjet printing, please name that person.

A week or so back, I made it clear to the list that I use sRGB in my workflow. I use Iris 3047 printers in the reproduction of artwork. Of course we use them to create original work ie. photography and digital artwork.

me 11/15 approx

For what it's worth, I will share with you my solution.

I work in sRGB space for reouching and intial contrast and color correction. It makes no sense to me to have a color space that my monitor cannot show me.

I would add that by using my rip software, I can color correct in 1/2 percent or even 1/10 percent values. By correcting in cmyk I can do very cool and effective corrections. Perhaps if I could afford an Eizo and all new profiling software it might, be worth it to do aRGB or Pro rgb. If I was using an Epson it would be a different story for me.

Thanks,

Greg Welch

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The Color of Nature: ProPhoto vs. SRGB

Posted by: "Paul Foerts"

Tue Nov 21, 2006 9:50 pm (PST)

"Richard Wagner" wrote on Mon Nov 20, 2006 8: 27 am ((PST))

... Atkinson worked with Vanfu in Japan to achieve a breakthrough in wider

gamut printing from a standard offset press.

They used highly concentrated inks, optimized ink densities, hybrid screening,

high quality paper, and accurate color management to increase the total gamut

volume by 1.6, which allowed his exquisite photographs of gem-quality rocks to

print beautifully. They achieved higher quality printing at lower cost by using color management instead of expensive trial and error on press, and they developed methods that

they feel can be applied to other offset presses.

Can you prove this?

Was it a 4 or 6 color job?

Did they use soft/hard proofing? What proofing device/method?

How was the total gamut valume increase calculated? Was is relative, perceptual or absolute?

If they used an experimental inkset, how did they scientifically optimize their densities without test runs?

Every color that can be perceived in the mind's eye is a color of nature, and

Atkinson' s images show colors that are nearly surreal.

If you've never seen his work, spend 5 minutes here (realizing that the colors

are limited to the gamut of your display!)

What are you trying to sell?

A few specialized printers are producing limited edition "works of art". They all use proprietary technology and their "own" color management.

They all practice trial and error... as you do. Because as you say: the colors are limited to the gamut of your display!

Best,

Paul Foerts

PS. Photographers don't use crayons, they use cameras : -))))

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: "Michael King”

Wed Nov 22, 2006 5:14 am (PST)

Ok so after some more testing its clear the OOG colors were a side effect of sharpening. I have in camera sharpening set to check focus and Nikon Capture picks up that flag and applies sharpening to the NEF. I usually deselect it in NC, but had forgotten to do that this time.

Mike King

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Re: Handling OOG Colors (was RGB Working Space)

Posted by: Dan Margulis

Wed Nov 22, 2006 8:55 am (PST)

Bill Theis writes,

But this begs the question: is there any utility at all for the Photoshop

gamut warning? or is it just too crude for critical work that would better be done by continuously monitoring the lightest parts of the channels for details?

Well, let's put it this way. I just opened a couple of reasonably saturated images in Adobe RGB and did Convert to Profile>ProPhoto. Then I set Adobe RGB as the proofing space and turned on the gamut warning. A significant proportion of the images was reported as out of Adobe RGB gamut, in spite of the fact that they had been exported unchanged from Adobe RGB.

So, yes, in a gross sense it's usable if you ignore what it shows in the shadows, but it is not as good as examining the channels, although much quicker.

Dan Margulis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Mark Segal

Wed Nov 22, 2006 8:56 am (PST)

Andrew, I work routinely in ProPhoto space because on the whole it makes no visible difference on a print relative to working in ARGB98 space, but I like the idea of the insurance policy in case one day we really do get wide-gamut output devices. There are, however, occasional situations in which ProPhoto is less than satisfactory. Quite some time ago I have discussed with both you and Dan my "Chinatown Red" syndrome, (in that case for scanned negatives) where the highly saturated reds in Pro Photo space come out of the printer with the detail obliterated. When the image is re-scanned with Silverfast in ARGB98 the detail comes back. I'm not sure how this case would relate to digital capture and raw file processing, but it is prime-facie evidence that at least Silverfast performs gamut compression that rescues detail otherwise lost. However as far as the hue of the red goes, it cannot solve what the printer can't print.

Mark Segal

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Wed Nov 22, 2006 11:12 am (PST)

On 11/22/06 7:08 AM, "MARK SEGAL" wrote:

Andrew, I work routinely in ProPhoto space because on the whole it makes no

visible difference on a print relative to working in ARGB98 space, but I like

the idea of the insurance policy in case one day we really do get wide-gamut

output devices. There are, however, occasional situations in which ProPhoto is

less than satisfactory. Quite some time ago I have discussed with both you and

Dan my "Chinatown Red" syndrome, (in that case for scanned negatives) where

the highly saturated reds in Pro Photo space come out of the printer with the

detail obliterated. When the image is re-scanned with Silverfast in ARGB98 the

detail comes back. I'm not sure how this case would relate to digital capture

and raw file processing, but it is prime-facie evidence that at least

Silverfast performs gamut compression that rescues detail otherwise lost.

Well it doesn©ˆt tell us anything about raw capture true. I©ˆd prefer to see such a file. As for a color neg, and that color space, the question becomes far more complex such as what kind of scanner profile and it©ˆs gamut and qualities might have on the scan as well as the scanner settings. It would be interesting to see if just using a different scanner driver and the same space or using a different input profile (if you even have one for a scan of a neg) would produce differing results. A heck of a lot of variables to place the blame solely on the encoding color space. With a raw file, much easier. And I suspect you©ˆre not wishing to send the color neg to folks to test on their end.

Have you ever seen a similar issue with a transparency using the same basic setup?

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Henry Davis

Wed Nov 22, 2006 11:12 am (PST)

The problem has been described as being an issue mostly for the uninitiated, uninformed or unaware. It has been stressed repeatedly that professionals who are aware of the issues involved in wide gamut editing are not the group being addressed with these cautions.

Andrew, you are keen and knowledgeable on this topic. There are many, many people who are not, and yet they find themselves handling picture files of any and all descriptions and encodings from unknown sources. Some of them have very little time to prepare these files for print, much less do they have time to pursue detective work and carry on esoteric conversations with file deliverers who may, or may not, have any clue themselves about encoding.

Again, I believe the cautions are directed to a general audience, and I would ask that you consider - just for a moment or two, that the cautions may have a beneficial aspect as well. It would be nice to see your list of the beneficial aspects that might result from the cautions of wide gamut editing(if you believe there are any).

As to your challenge to supply a file - it misses the point. The challenge would be to supply several differing raw files to a sample of unknowledgeable and unsuspecting individuals, not to a trained pro. Instruct them to edit and print in wide gamuts. Then see the printed results.

Henry Davis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Wed Nov 22, 2006 11:13 am (PST)

On 11/22/06 10:53 AM, "Mark Segal" wrote:

There are no scanner profiles for color negative films.

Not real ones <g>. The Imacon has a profile used (FlexTight Input) specifically for scanning negs. It©ˆs supposed to be a ©¯null©˜ profile.

That is why Silverfast provides "Negafix" which is a post-scan pastiche to

correct for what a profile would do if there were one. In Silverfast you

select the bit depth, color space and x other variables you want and then

scan. If you set it up right it does a very good job of converting the raw

scan to a decent image.

Yes I own the product and agree, it does a really good job with color negs.

Now, that does not fully address why the detail got smashed in the original

scan.

Exactly. It could be a bug, it could be due to the gamut of the color neg, it could be due to something else like the orange mask or something I©ˆm not even thinking about. Again, I don©ˆt know there©ˆs enough evidence to suggest it©ˆs only ProPhoto RGB but its certainly possible. There©ˆs no question that in your case, switching color spaces fixed the issue but I©ˆm not sure that points to ProPhoto being the sole cause (I should write to Karl Heinz Zahorsky to see if he©ˆs got a suggestion). That©ˆs why I©ˆd prefer to see what a raw file does upon rendering and subsequent encoding with ProPhoto in any case where this obscures detail as you have seen with the neg.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Henry"

Wed Nov 22, 2006 11:19 am (PST)

Coke Red is Coke Red. Even though there are process builds that are acceptable for certain print delivery, but when it really counts(like in advertising photography), Big Red pays for a spot ink that matches their trade color. Same goes with their other brand colors. In advertising, many times comps are made and used specifically for the shoot. Actual production pieces would be of lesser quality, and therefore unsatisfactory - especially for close-ups.

When the can in the snow was printed, there was probably a person on the line comparing the printing to standards, thus keeping color within an acceptable range.

Henry Davis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Mark Segal"

Wed Nov 22, 2006 11:20 am (PST)

Re: The Color of Nature: ProPhoto vs. sRGBAndrew,

There are no scanner profiles for color negative films. We've been through this before. That is why Silverfast provides "Negafix" which is a post-scan pastiche to correct for what a profile would do if there were one. In Silverfast you select the bit depth, color space and x other variables you want and then scan. If you set it up right it does a very good job of converting the raw scan to a decent image. With these highly saturated reds that envelop detail I want to preserve, when I scan selecting ProPhoto I got a blotch with no detail, and when I repeated the scan using ARGB98 I got the detail back. All else is equal between the two scans, so we're not talking about multiple variables affecting the latter outcome. Whatever set of original conditions caused the original scan to obscure detail in highly saturated red was cured by the simple reduction of the color space gamut on the re-scan. Obviously, desaturation of reds is taking place as part of the gamut compression between ProPhoto and ARGB98, and the desaturation unveils the detail that got smashed.

Now, that does not fully address why the detail got smashed in the original scan. I attribute it to the colour space for two reasons: (1) the change of color space corrected the problem, and (2) in principle, a very wide colour space can admit highly saturated colours that obscure detail embedded within them. I'm not the first one to observe that. But I repeat - this is not a general argument against using ProPhoto as a default editing space - I am only saying that it is most likely not fail-safe in all circumstances.

I have not scanned enough transparencies to have useful evidence about this issue. In my film days (which ended for good in 2004), virtually all my colour work was done using negative film.

Mark Segal

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Wed Nov 22, 2006 1:04 pm (PST)

On 11/22/06 10:51 AM, "Henry" wrote:

The problem has been described as being an issue mostly for the

uninitiated, uninformed or unaware. It has been stressed repeatedly

that professionals who are aware of the issues involved in wide gamut

editing are not the group being addressed with these cautions.

Oh, I see. So this is no different from uneducated users who over sharpen images (USM is dangerous), resize files too small (Image size is dangerous), apply way too much JPEG compression (JPEG format is to be avoided and dangerous) or users who pull steep curves. We should debate all and every possible hurt me button found in Photoshop on this list because someone might hose their data. What you©ˆre saying is, if you know how to drive the application with any degree of competence, so called Ultra Wide gamut spaces are OK?

Again, I believe the cautions are directed to a general audience, and I

would ask that you consider - just for a moment or two, that the

cautions may have a beneficial aspect as well.

Can we define Œgeneral audience©ˆ? Seems pretty broad. So the recommendations are, funnel our colors into a dated color space because someone may have no clue how to handle a file that only looks reasonable on a web page? I thought this was a color theory list.

It would be nice to see

your list of the beneficial aspects that might result from the cautions

of wide gamut editing(if you believe there are any).

I©ˆve done this till I©ˆm blue in the face. The benefits are simply containing colors your capture device can produce and printing colors your output device can reproduce. As such, in many, many cases, the only space that can accomplish this is ProPhoto RGB or an equally large gamut color space.

As to your challenge to supply a file - it misses the point. The

challenge would be to supply several differing raw files to a sample of

unknowledgeable and unsuspecting individuals, not to a trained pro.

Instruct them to edit and print in wide gamuts. Then see the printed

results.

No, it doesn©ˆt miss the point which is, according to some, there are severe and dangerous issues when using a wide gamut working space. And how do you define an unknowledgeable and unsuspecting individual? So we make everything we do so idiot proof that only an idiot would use it?

It©ˆs nearly impossible to define a scenario that specifies a safe practice for all users. Are you suggesting that a pure, sRGB workflow always ensures that all users, no matter their knowledge can©ˆt hose a file? On the other hand, it©ˆs very easy to illustrate the benefits of a wide gamut working space both by using simple math, applications that plot the gamuts of images and output device and by using a simple test such as printing out a file. As I©ˆve said, I©ˆve illustrated an example where any working space other than ProPhoto RGB will create visible degradation using a few simple Photoshop edits. The single response I got to this challenge is that those edits (a boost in saturation using Hue/Sat) would only be applied by a so called unknowledgeable and unsuspecting individual. Oh, so in this example, it©ˆs OK to dismiss what is a common Photoshop edit move but its not OK to use such a large gamut space because the same unknowledgeable and unsuspecting individual might hose the file? I fail to see the logic.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Lee Varis"

Wed Nov 22, 2006 1:06 pm (PST)

On Nov 21, 2006, at 6:51 PM, Andrew Rodney wrote:

So, we've got a pundit saying ProPhoto is dangerous and as yet, many of us

are waiting for a raw file that illustrates this that we can prove ourselves.

Andrew... the RAW file isn't the point! Why do you insist on framing the debate this way? Its very simple - the debate such as it is, concerns the use of ProPhoto as an EDITING space -- you're the only one talking about RAW files!

I think its ludicrous to say that ProPhoto is a better editing space when the data points are spread out over such a large color volume – small moves in Photoshop will always have a bigger effect in ProPhoto. Much of the color adjustments that end up being done every day are subtle and subtle moves are easier done in a smaller color space.

NOBODY is arguing that ProPhoto shouldn't be used as a container of full gamut imagery BUT if it is your intention to EDIT the file after capture to achieve a result that alters color relationships in any creative way it just makes a lot more sense to be able to see ALL the subtle color relationships you are altering before you make a print – otherwise we're back in the pre-color management days where you have to make adjustments after you've seen a print.

Its obvious that if you need the extra gamut you HAVE to use ProPhoto but if you don"t there's NO reason to advocate its use for editing purposes.

I repeat -- the RAW file never enters the discussion!

Users who routinely work with super saturated images can use ProPhoto all the time if they want but I don't see how you can possibly make the claim that its easier to use ProPhoto than Adobe RGB or even sRGB. In the smaller spaces you can easily SEE whether you've "hosed" the file. In ProPhoto is is very possible to do an edit that sends areas into hyper color clipping zone without clipping values in the grayscale channels. So the only way you'd really know (because you can't see these colors on screen anyway) is to make a print. How is this easier.

So, when framed this way - Is it easier to edit color in sRGB or Adobe RGB, how do you answer. Anybody in his right mind would say sRGB – does that make it better? Not necessarily, depending on the image. Is it easier to EDIT color in Adobe RGB or ProPhoto? Duh... Adobe RGB is easier to use than ProPhoto! Does that make it better? again, not necessarily, depending on the image and what you're trying to achieve! So why get your knickers all in a twist. Use ProPhoto all you want if you're an expert (I assume you are, right...) but you can't possibly advocate that its EASIER to use all the time!

regards,

Lee Varis

President, LADIG

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Wed Nov 22, 2006 2:04 pm (PST)

On Nov 22, 2006, at 12:51 PM, Henry wrote:

The problem has been described as being an issue mostly for the

uninitiated, uninformed or unaware. It has been stressed repeatedly

that professionals who are aware of the issues involved in wide gamut

editing are not the group being addressed with these cautions.

Not that I've seen. Call me dense, but I've been asking about this and don't believe that I've gotten a reply. There seems (to me) to be a lack of movement on both sides. If it's only a matter of avoiding OOG colors (which are much easier to call for in wider spaces) then I'd agree that the warnings are for the "uninitiated, uninformed or unaware". However, this is not the impression I've gotten from those that say working in an Ultra Wide Gamut space makes *no* sense except under exceptional circumstances. OTOH, the lack of warnings about the pitfalls from the Ultra Wide Gamut proponents makes me suspicious of their claims as well. I don't think it's wrong to ask for examples which can be confirmed or refuted.

Dan wrote an entire book about why a more common use of Lab is warranted (and included a good deal of specific information on potential pitfalls and when it is not the best choice), and Lab is at least as susceptible as ProPhotoRGB to creating OOG colors. This can't be his or other opponent's only reason for stating that adopting this space is a recipe for inferior images.

The anti ProPhotoRGB position appears (to me) to be that it can lead to lower quality except in the exceptional circumstances when the colors you have in the image are out of a "normal" space's gamut *and* outputting these colors is important to your interpretation of the image. I believe the (reasonable) pro ProPhotoRGB position is that you need to be careful setting colors you can't see with your monitor with any space that's larger than sRGB and that using ProPhotoRGB is no different and has no other downsides that argue against it's use. If I've gotten this wrong I expect I'll hear. I think both sides need to back up what they say with facts and examples.

Ric Cohn

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "MARK SEGAL"

Wed Nov 22, 2006 2:06 pm (PST)

Lee, I just finished processing and printing a bunch of photos I made in London with my Canon 1Ds. I did all the work in ProPhoto, 16 bit. These city-scapes are anything but super-saturated - in fact most of them are pleasantly low key "city"-looking - they kind-of have the feel of old Agfacolor (but much better quality) if you remember those days back in the 1950s, and there is nothing the least bit hosed about them. I think you may be over-stating the case.

Mark Segal

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Wed Nov 22, 2006 5:46 pm (PST)

On 11/22/06 9:29 AM, "Lee Varis" wrote:

Andrew... the RAW file isn't the point! Why do you insist on framing

the debate this way? Its very simple - the debate such as it is,

concerns the use of ProPhoto as an EDITING space -- you're the only

one talking about RAW files!

Lee, you HAVE to encode the raw data into a working space. If you do this in anything smaller than ProPhoto RGB, you can't get the lost data back (unless you re-render the data which is a big waste of time).

Once you encode the data, yes you have pixels you wish to edit. As yet, no one has provided a file that illustrates all the dangers of a wide gamut space. Why a RAW? Because I can handle all the encoding and place that into ProPhoto without any worry that the pixels have been degraded prior to hand off of the data.

And you can do a heck of a lot of editing in the raw converter without even rendering a single pixel.

I think its ludicrous to say that ProPhoto is a better editing space

when the data points are spread out over such a large color volume ú

small moves in Photoshop will always have a bigger effect in

ProPhoto.

So what? I'm waiting on proof that's an issue for someone who knows how to apply edits to this data. Using your logic, we should use a tiny color space for fear of distance between a high bit file (with at least 4096 steps from black to white) and instead, toss away usable color I can capture and output. That's the lesser of two evils? We should agree to disagree.

Much of the color adjustments that end up being done every

day are subtle and subtle moves are easier done in a smaller color

space.

Easier?

NOBODY is arguing that ProPhoto shouldn't be used as a container of

full gamut imagery BUT if it is your intention to EDIT the file after

capture to achieve a result that alters color relationships in any

creative way it just makes a lot more sense to be able to see ALL the

subtle color relationships you are altering before you make a print ú

We've been down this path. You can't see all the colors anyway and the reference media is such that your soft proof is never 100%. The final print is key here and as yet, no one has proven that the prints I have in front or me which show a quality improvement in a wider gamut space isn't a good.

I repeat -- the RAW file never enters the discussion!

I repeat, of course it does. You can't have a rendered file without defining a working space.

Is it easier to edit color in sRGB or

Adobe RGB, how do you answer.

I don't find either easier or harder. Neither fits my output color space. Neither provides a prefect soft proof. One provides a visible advantage on output to my wide gamut printer. But it's not easier, it's superior.

Is Elements easier to use than Photoshop? Which do you use?

Is the Auto buttons seen throughout Photoshop easier to use then the more advanced controls and which do you use? I don't see easier as a compelling reason to toss what is clearly defined data I can capture and output. But maybe I'm more concerned with my data than others.

This easier mindset is similar to the recent argument that what we do should be safer for uneducated users of Photoshop. That we should dumb everything down for dumb users (and now you're suggesting lazy users or at least those who weight easier over better). The easier approach once again produces visible damage to images in any space but ProPhoto once again illustrated by actual sample files supplied to the list.

So far, the only rational you and a few others have come up with against ProPhoto workflow is its not as easy and unskilled users might hose the file. So I'll admit that if you're either kind of user (not skilled and wanting the easiest way to edit your images), you probably shouldn't look into ProPhoto RGB or even Adobe RGB (1998).

This is getting to be a pointless debate. As yet, no one has provided a file, preferably a raw that allows me to, as you say, alter the huge spread of colors in a wide gamut space, that illustrates any issues when handled by a skilled end user. Therefore I can only believe this is yet another religious argument with science on one side (providing math, files and output) versus a group that hasn't anything to back up their claims as yet to the evils of 'ultra wide gamut' spaces. Easier isn©ˆt a metric you can measure. Unknowledgeable and unsuspecting individuals who might damage a file can©ˆt be defined. This all smells of the old 16-bit debate which as Bruce Lindbloom so elegantly described:

"When considering all images showing no 16-bit advantage, 16-bit images show no advantage."

We should add ProPhoto RGB to the above.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Wed Nov 22, 2006 5:53 pm (PST)

On Nov 22, 2006, at 11:29 AM, Lee Varis wrote:

In ProPhoto is is very possible to do an edit that sends

areas into hyper color clipping zone without clipping values in the

grayscale channels. So the only way you'd really know (because you

can't see these colors on screen anyway) is to make a print.

Thanks Lee, finally a fact I can get my head around! This is a good point. However, I'm not sure the answer isn't the same as for visualizing how any RGB file will look when converted to a smaller space: Proof Setup. I agree this makes it more difficult to work with a larger space, much like there are things about working in RGB that are more difficult than converting immediately to CMYK and working there. As things change and methods improve we learn new ways. Whether a more difficult workflow is worth adopting should be determined by balancing the benefits with the drawbacks.

What I don't understand is the desire to sell working in Ultra Wide Gamuts to the "masses". With the majority of image creation going to digital, the de facto encouragement to move from ACR to ProPhoto (8 bit or 16 bit) seems odd or maybe naive. It will take some very strong proof before I would agree that it shouldn't be considered an experts only decision.

Ric Cohn

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Michael Plack"

Wed Nov 22, 2006 7:16 pm (PST)

Several years ago an expert in the field recommended converting output images to colormatch because, in his opinion, it most closely matched the color gamut of the older Epson printers most of us were using at the time. I followed his advice and was happy with the results. That was my introduction to profiling and the concept of marrying camera, monitor and printer into a system designed to produce images with acceptable color characteristics.

Perhaps a little backward thinking would be practical here. The printer's gamut might be the first consideration in choosing the image's working space. It makes no sense to produce an image in a color space many of whose subtle tones will be clipped from the printed image. Future use considerations warrant choosing a larger color space for producing the image after RAW conversion, but a final conversion to the most practical vis-a-vis the printer makes sense to me.

Michael Plack

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Re: The Color of Nature: ProPhoto vs. SRGB

Posted by: Richard Wagner

Wed Nov 22, 2006 11:08 am (PST)

On Nov 21, 2006, at 2:20 PM, Paul Foerts wrote:

Can you prove this?

No, but the information is from Bill Atkinson's presentation on his book. If you'd like to call Bill Atkinson a liar, or ask him if he can "prove it," that's your call. Bill Atkinson donates an unbelievable amount of his work, time and technical prowess back to the photographic/art community.

http://homepage.mac.com/billatkinson/FileSharing2.html

Was it a 4 or 6 color job?

Did they use soft/hard proofing? What proofing device/method?

Bill is very open about his techniques/processes, and if you e-mail him and ask (politely), I'm sure he give you all the details you'd like. You could also look through the online presentation that he created describing the making of the book.

How was the total gamut valume increase calculated? Was is relative,

perceptual or absolute?

This makes no sense. It is the ratio of the gamut volume of the CMYK with the new inks/process to the gamut volume of "standard" CMYK (e.g., SWOP). Rendering intents are irrelevant in this calculation and in gamut volume in general.

If they used an experimental inkset, how did they scientifically optimize

their densities without test runs?

An entire new set of inks were developed. Sure, lots of testing was done to develop the system, but just like profiling a printer, once it's done, you can print away. The inks that were developed are now commercially available from TOYO.

http://www.printondemand.com/MT/archives/009643.html

<<TOYO's Kaleido CMYK Offset Inks Expand Color Gamut

Graph Expo 2006 - ADDISON, IL, October 6, 2006 - The newly developed TOYO King HyUnity soy Kaleido inks are unique four-color process inks that offer a larger color gamut that is closer to RGB without using fluorescent pigment. TOYO INK reengineered the existing CMYK (cyan, magenta, yellow and black) colors to create new, dedicated pigments. These new pigments eliminate the narrow gamut problems related to four-color printing. Kaleido expands the CMYK color gamut to nearly reach the color representation of the original RGB color range.

Chasing the RGB Colorspace

Digital cameras, scanners, monitors and software in the current prepress workflow operate in the wide RGB color range. The appropriate settings are chosen in the image processing software, such as Adobe RGB (1998) color gamut (which covers most colors). In the subsequent four-color printing process, image reproduction is limited to the narrower CMYK color space. Color management profiles limit the larger RGB gamut in order to provide color consistency in prepress and printing processes. Reproducing images with colors beyond CMYK requires a six-color or seven-color printing process. Ordinarily, customers and printers avoid the added expense associated with this process and settle for the limited color range of four- color printing. Kaleido inks make it possible to achieve a color gamut that approximates six- or seven-color printing. Kaleido's reproducible range matches almost exactly images of comprehensive designs obtained from inkjet printers and high-end direct digital color proofing. Kaleido inks have their own color profiles designed to maximize the effects of the Kaleido color gamut. This allows prepress and press professionals to increase customer satisfaction.

But guess what? Some of those colors are going to be OoG on your monitor, just like with inkjet printing.

What are you trying to sell?

Reality. Change. Progress. Improvement. I've invested a lot of time to this List to try to enlighten list members about changes that are occurring in the industry, often by referencing new ISO or ANSI specifications or technical reports or research papers to support my statements. The hostility toward anything other than the status quo here is rather impressive. I get nothing for the time I've invested, other than the satisfaction of hearing from a number of people who've contacted me off-list to state that they now "get it" after playing with their own images and printers and reading some of the references. I get a full-frontal assault from many of those who are very resistant to change. If I were "selling something" to this market, it would be a very bad business deal with a low return on investment. It's too bad, because there are otherwise a great many good ideas that come out of this group. C'est la vie.

--Rich Wagner

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Re: The Color of Nature: ProPhoto vs. SRGB

Posted by: "Ric Cohn"

Wed Nov 22, 2006 1:07 pm (PST)

On Nov 22, 2006, at 12:07 PM, Richard Wagner wrote:

I've invested a lot of time

to this List to try to enlighten list members about changes that are

occurring in the industry

Richard,

I appreciate the time and effort you've put in. I've found it very interested and I've benefited from it. I hope you'll continue to do so. The lively debate on this forum is not always perfect. However, I do believe you need to acknowledge when you've misunderstood or inadvertently misstated anyone's position. This is part of a civil discourse and eliminates the appearance of having an agenda.

Respectfully,

Ric Cohn

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Re: The Color of Nature: ProPhoto vs. SRGB

Posted by: "RJay Hansen"

Wed Nov 22, 2006 5:56 pm (PST)

On 11/22/06, Richard Wagner wrote:

Reality. Change. Progress. Improvement. I've invested a lot of time

to this List to try to enlighten list members about changes that are

occurring in the industry

Well it's not as if you come off sounding condescending or anything.

Please pardon us luddites who haven't been able to face the error of our ways.

RJay Hansen

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Re: The Color of Nature: ProPhoto vs. SRGB

Posted by: Andre Dumas

Wed Nov 22, 2006 9:17 pm (PST)

Hello Richard,

Thank you so much for the time that you have invested on this list. The knowledge that I have acquired here is invaluable and I am grateful to all those who are taking the time to share their knowledge on such a complex, and interesting subject. Thanks Dan for providing us with this meeting place and Richard may I simply say that I am reading each one of your posts with great interest and have gained a lot from the precious information which they contain.

André Dumas

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Re: RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Wed Nov 22, 2006 5:51 pm (PST)

Olivier writes,

However, as far as I am concerned, I don't manage to have a clear

understanding of what is Dan's thinking and recommending for modern

LFP printing. Would you please care, Dan, expanding again further on

what is your view of best correcting images for modern LFP output.

I am sorry that I am not familiar with the acronym LFP. However, let me say that my correction philosophy depends very little on the output device. Each one has a different set of achievable numbers, but the basic principles remain the same whether preparing a file for newsprint or for a 12-color inkjet. The main variables are that with poorer output conditions one has to be more aggressive (as in allowing highlights to blow out or shadows to plug in order to increase contrast elsewhere) and that when the reliability of the process is uncertain one has to bias the correction in the direction of the least objectionable variation (as by deliberately making a sky more cyan, to eliminate the possibility that it may go purple due to poor printing.)

Dan Margulis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Andre Dumas

Wed Nov 22, 2006 9:31 pm (PST)

--- Andrew Rodney wrote:

One provides a visible advantage on output to my wide gamut printer.

But it's not easier, it's superior.

Hello Andrew,

I tried the following test:

1- starting in ACR with _MG_0126.DNG in ProPhoto 16 bit I made the best adjustments I could retaining a maximum of texture in the petals of the yellow flower avoiding *all* blown out highlights and plugged up shadows. My results were identical to Dan's L_MG_0126-versionL.psd.

2- I opened it in Photoshop, reduced it to 4x6 and did *no* further corrections. Converted to my Epson R800 profile and printed it on Epson Glossy paper.

3- I went back to the ProPhoto (to before the convert to printer profile) and converted to sRGB and then to my printer profile and printed it.

Using a magnifying glass I cannot detect any differences between the two and that makes sense to me (?) because both were reduced to one single denominator *my printer profile*. My R800 is a fairly recent 8 colors printer.

So wouldn't you say that the printer profile plays an important role regarding the advantages of a large gamut vs a small gamut working space? I haven't seen this discussed here (at least not specifically) or did I miss something?

André Dumas

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Rich Wagner"

Thu Nov 23, 2006 12:02 am (PST)

Ric,

I agree that working in ultra-wide gamuts is not for the masses, if you define masses as the gneral public. For the masses, everything should be transparent and out of reach. Let the photofinishers handle their images with tricks like the extended-gamut sRGB's, etc. For those who are not the masses, but are instead rather sophisticated in their use of tools (read - this list, and many pro photographers not on this list), ProPhoto should be an viable option, not an 8-letter curse word. ACR does all of its work in ProPhoto. Not accidentally, it was chosen as the internal working space of ACR by Adobe engineers. That's where most of the heavy lifting should be done. Large edits in images output from ProPhoto should not be needed very frequently. If large edits aren't needed in PS, there should be no problem using it as a working space/archive space or print source space. This group of users should be using at least AdobeRGB anyway if distributing images for publication or if making fine-art prints (according to almost all current recommendations). As Andrew has repeatedly pointed out, images in ProPhoto showing massive problems on conversion down to other spaces are very rare. Most of us using ProPhoto on a daily basis simply don't run into this problem.

Best,

--Rich

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Stephen Marsh

Thu Nov 23, 2006 1:10 am (PST)

Rich Wagner wrote:

ACR does all of its work in ProPhoto. Not accidentally, it was

chosen as the internal working space of ACR by Adobe engineers.

That's where most of the heavy lifting should be done. <

Rich, to be clear - this is not the same thing as working in ProPhoto on rendered images inside Photoshop, if I understand things correctly. One is working on raw linear sensor data and the other is working on a rendering into a gamma of 1.80. ACR/Lightroom use a linear encoding, which Andrew informs the list is the same as gamma 1. So would one not have to use a custom RGB, based off ProPhoto but changing the gamma to 1.00 and then use that in Photoshop? I doubt most members of this list or the ColorSync Users list would feel comfortable doing that in Photoshop outside of a raw converter. So my point here is that it is not comparing the same thing, as the editing spaces are different and the data is different. I would be happy with the statement that ACR works in a special space with ProPhoto RGB primaries but not with ProPhoto gamma (then there is the whitepoint too).

I have listened to the ALR podcast more than once, the primaries were chosen as it is a large gamut (so why not WG primaries or CIE?). The explanation of why linear gammma is used was less than helpful, and the hybrid sRGB tone response for display has been a source of confusion for some out there.

LAB edits are often different to those performed in RGB, so even though ProPhoto and LAB are huge, the application of edits will have a different result so this is another case like the above where it is perhaps not fair to compare things as equal in all cases.

Sincerely,

Stephen Marsh.

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Stephen Marsh

Thu Nov 23, 2006 2:38 am (PST)

Andrew Rodney wrote:

And we have a series of images that illustrate that in any space BUT

ProPhoto RGB, a series of Photoshop edits will produce visible image

degradation no screen and in print.

I can't let this go Andrew, but you did not agree to disagree with me! Did you miss my earlier reply?

It is easy to demonstrate that it is the edit and not the editing space. I invite interested parties to try the simple experiment themselves, it only takes seconds and has a huge impact on image quality.

1. Use the saturation slider in ACR to punch things up, while in ProPhoto. Now repeat. Compare to the same slider setting in sRGB while ACR. Then perhaps compare a stronger setting in sRGB if you like. This is to demonstrate what a good saturation command does in either space.

2. Back in ACR turn saturation back to zero and render a ProPhoto vesion. In Photoshop, use the Hue/Saturation command adjustment layer in normal blend mode to push saturation. Go back and repeat these steps with the only difference being the adjustment layer blending mode being set to either color or saturation modes.

Compare the normal blend to the color/saturation blend. Normal has extreme damage while color blend does not.

Even in ProPhoto, one can rescue lost detail when pushing things by using either color or saturation blending instead of normal blending.

I can choose to make the image fall apart in sRGB by not using the command in ACR or by not using color/saturation blending in Photoshop.

But why?

Just increase saturation in the RAW converter! Or just use color or saturation blend modes with the H/S command in Photoshop.

So, we have a common issue here. Popping saturation can lead to loss of detail, posterization and other artifacts.

There are three ways that I know of to combat this issue.

1. As Andrew suggestts, just use a larger gamut to reduce or perhaps avoid the problem - even if the edit is known to be second-class, the gamut of ProPhoto will negate the poor choice of edit.

2. At the AIM site, Timo has a different approach:

http: //www.aim-dtp.net/aim/photoshop/v6/better_sat/index.htm

3. While I simply suggest separating colour from tone when increasing saturation, which is the main issue (I do concede that gamut plays a role, just not as much as using color/saturation blending). Or use LAB. It is not the gamut of LAB, but the AB split from the L that is the key (or LCH, , HSL, HSB etc).

Sincerely,

Stephen Marsh.

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Thu Nov 23, 2006 3:31 am (PST)

Stephen,

I only meant to imply that major edits should be done on the RAW data, in ACR, for the reasons stated in the RIMM/ROMM paper and Ch. 4 of Sharma's Digital Color Imaging Handbook. Obviously, there is a big difference between the scene-referred data and the output-referred data.

Thanks,

--Rich Wagner

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Bob Frost"

Thu Nov 23, 2006 3:34 am (PST)

Ric,

What I don't understand is the desire to sell working in Ultra Wide

Gamuts to the "masses".

The 'masses', i.e. the vast majority of digital camera users, use sRGB. Their cameras only do sRGB, their monitors only show sRGB, and their printers (home or professional) insist on or default to sRGB). Some may have heard of AdobeRGB, but few, if any, have heard of ProPhotoRGB or Lab or any other color space. And they all take jpegs, not raw, so don't know what ACR is.

Those on this list are the small expert 'minority' who have heard of all three, and know what color management means. Mainly professionals.

So the 'sell' (if that is what you want to call it) of ProPhotoRGB by the 'ROMMulans' (to continue the StarTrek analogy) is surely from one group of the expert small minority to another group of the expert small minority?

Bob Frost

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Thu Nov 23, 2006 3:38 am (PST)

On Nov 23, 2006, at 3:04 AM, Stephen Marsh wrote:

1. Use the saturation slider in ACR to punch things up, while in

ProPhoto. Now repeat. Compare to the same slider setting in sRGB while

ACR. Then perhaps compare a stronger setting in sRGB if you like. This

is to demonstrate what a good saturation command does in either space.

Stephen,

I'm not sure I follow the details. Is the image ideally adjusted in ProPhoto, then the output space changed to sRGB in ProPhoto without changing any other ACR settings? If so, the sRGB image will likely be OoG immediately, before touching the Sat slider.

Thanks for clarifying this so that I can follow you.

--RIch Wagner

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Bob Frost"

Thu Nov 23, 2006 3:40 am (PST)

Andre,

So wouldn't you say that the printer profile plays an important role

regarding the advantages of a large gamut vs a small gamut working

space? I haven't seen this discussed here (at least not

specifically) or did I miss something?

You missed something!

Bob Frost.

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Stephen Marsh

Thu Nov 23, 2006 4:07 am (PST)

Richard Wagner wrote:

Stephen,

I only meant to imply that major edits should be done on the RAW

data, in ACR, for the reasons stated in the RIMM/ROMM paper and Ch. 4

of Sharma's Digital Color Imaging Handbook. Obviously, there is a

big difference between the scene-referred data and the output-

referred data.

We have to take extra care with our wording on this list, I just wanted it to be clear that ACR/Lightroom was only using ProPhoto RGB primary values was not the same as rendering, converting to or editing using ProPhoto RGB ICC profile.

As always, it is the fine points that cause questions and debate.

Thanks for the earlier pdf links, such terms are new for me.

Regards,

Stephen Marsh.

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Stephen Marsh

Thu Nov 23, 2006 4:18 am (PST)

Richard Wagner wrote:

Stephen,

I'm not sure I follow the details. Is the image ideally adjusted in

ProPhoto, then the output space changed to sRGB in ProPhoto without

changing any other ACR settings? If so, the sRGB image will likely

be OoG immediately, before touching the Sat slider.

Thanks for clarifying this so that I can follow you.

Rich, the ACR saturation test is just for a baseline to compare against, it plays no role in my ongoing debate with Andrew on the Photoshop Hue/Saturation command in normal/saturation blending and the subsequent results on the image due to the edit and *NOT* the gamut of the editing space.

The same edit in sRGB results in less saturation than ProPhoto (as expected). The PP yellow is clipped on display, but it looks better than sRGB due to gamut. One can use a stronger setting to get a closer result on the display as PP.

So ignore paragraph 1, the meat is at para#2.

Back to the main point (the above only distracts, it was intended to show that +saturation in sRGB does not hose the image, it shows how poor the H/S command in normal mode is when compared to ACR, ALR, blending modes or LAB). Normal blend could not be a worse choice for a +saturation edit in Photoshop, in either sRG or ProPhoto RGB.

In Photoshop (not ACR) using sRGB, a normal blend saturation move of say 15 hoses the yellow flowers. Change to sat/color blend and the image is not hosed.

So, always use color or sat. blends for H/S commands (or at least compare to normal blend on a case by case basis knowing that normal blend can hose an image.

Stephen Marsh.

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Thu Nov 23, 2006 8:42 am (PST)

On 11/23/06 3:04 AM, "Stephen Marsh" wrote:

It is easy to demonstrate that it is the edit and not the editing

space. I invite interested parties to try the simple experiment

themselves, it only takes seconds and has a huge impact on image quality.

I saw that and yes I agree that the editing is the issue in spaces other than ProPhoto RGB and agree this isn©ˆt the ideal edit move. But we©ˆve had two tracks here. One says, wide gamut spaces are dangerous to the uneducated user and a track that says, an uneducated user would apply the move I suggested which showed issues in all color spaces but ProPhoto RGB.

Should the tweak be done in any color space rather than in the converter? No of course not. And for a very interesting test, if you have Lightroom, crank up the Vibrance command (which is coming in ACR) and compare the rendered image in any color space compared to doing a similar saturation move using the Saturation slider. Big difference. This new command is doing a much better job not hosing the data.

1. Use the saturation slider in ACR to punch things up, while in

ProPhoto. Now repeat. Compare to the same slider setting in sRGB while

ACR.

Note that the processing here is happening in ProPhoto RGB (primaries and white point) gamma 1.0 for both edits. You©ˆre seeing the advantage of editing linear data in a linear tone response curve. You also get to see the effect on the Histogram and which encoding color space is the best fit or I should say, which will clip the colors once the rendering and encoding is finished and the file is sent to Photoshop. I think that©ˆs an additional advantage to doing this work in the converter, you can see the effect of the working space without having to worry about pushing the toothpaste back into the tube as you have to when working in Photoshop. I©ˆve yet to figure out how Lee decides after the encoding which space is the best fit (nor how working in Lab, a more or less, I©ˆd say larger gamut space is Œeasier©ˆ to work with due to the color spread).

Then perhaps compare a stronger setting in sRGB if you like. This

is to demonstrate what a good saturation command does in either space.

And again, if you have Lightroom, try the test above.

Just increase saturation in the RAW converter! Or just use color or

saturation blend modes with the H/S command in Photoshop.

In the converter. It©ˆs going to be less damaging due to the 1.0 encoding, its going to be faster and with metadata editing, you can apply any number of such edits and render any number of versions all with original pristine data (much like making multiple adjustment layers, until you stamp the edit on the pixels, its non damaging).

So, we have a common issue here. Popping saturation can lead to loss

of detail, posterization and other artifacts.

Agreed but this was less an issue in the wider gamut color space on the existing rendered image. So in this case, we have a color space that©ˆs less damaging for the uninformed user but according to some here, it©ˆs more dangerous for the uninformed user. That©ˆs my point.

Happy turkey day.

Andrew Rodney

___________________________________________________________________________

Wider Gamut Than ProPhoto RGB?

Posted by: Stephen Marsh

Thu Nov 23, 2006 2:24 am (PST)

Mike King wrote:

Is there a bigger space than ProPhoto I can use to visualise these

(using Colorthink)? It needs to be an RGB working space so that Nikon

Capture will convert into it. I want to see, for example, if they are

even visible colours.

Mike, you could invent one, Photoshop custom RGB in colour settings RGB pop-up creates matrix based monitor/working space profiles. But if you wish to use a known set, try Wide Gamut RGB and CIE RGB (even better than ProPhoto for channel blending!!!)

Hope this helps,

Stephen Marsh.

___________________________________________________________________________

Re: Request for Retraction (was The Color of Nature)

Posted by: Richard Wagner

Thu Nov 23, 2006 3:41 am (PST)

I've been away this past week and reading/responding to e-mail from a hotel room at night, and I'm now going through e-mail at 3:15 am. The volume of e-mail I go through is enormous, and I had chosen to pick and choose which messages/threads to read / respond to during the last week. Dan's "Request for Retraction" requires a response.

I have *never* knowingly misstated Dan's or anyone else's position about *anything* on this list, or anywhere else, and I resent the accusation that I would do so intentionally. It *is* certainly possible that I've misunderstood Dan's position or recommendations on many different issues, as I find much of his writing vague and without well-defined terms. If I have misstated his position, it was without intention or malice, and he has my sincere apology. Conversely, I would request that Dan refrain from accusing me of such intentionally malicious acts, and from repeatedly accusing me of "not knowing what a standard deviation is" or "what the definition of error is" or the definition of "quantization." My doctoral work involved Markov modeling of stochastic processes, I have a shelf full of statistics books, and I used to teach at the graduate level in biophysics. Sheesh! There's plenty that I know nothing about, but I know math/statistics better than most.

Dan, if I misstate your position on something, simply correct me. If I've misunderstood you, then someone else likely did as well. It is not helpful to anyone to muddy the waters.

On Nov 18, 2006, at 1:56 PM, Dan Margulis wrote:

To quote the pertinent section of Professional Photoshop 4E (2002),

p. 270: "The recommendations for the practical person, therefore,

are as follows:...[for] Work primarily aimed at non-Web RGB: If you

are certain that your workflow won't let anyone convert (or fail to

convert) it improperly later, use Adobe RGB."

This is from 2002, and I saw no recommendations for working spaces or output (other than sRGB and SWOP) in Canyon Conundrum, Dan's latest book. Dan, did you make a comparable recommendation in the 5th edition of Professional Photoshop? If so, can you give us the recommendation? In the 5th Edition, do you make recommendations for the Photoshop Color Settings? Setting up the default Color Settings is a fundamental part of using Photoshop.

On Nov 22, 2006, at 4:30 PM, Dan Margulis wrote:

However, let me say that my correction philosophy depends very

little on the output device.

That's useful to know. In Canyon Conundrum, Dan uses sRGB throughout and there is no discussion in that book of using a wider color space for "non-Web RGB." How is a reader to know that back in 2002, in a different book, Dan made the recommendation to use AdobeRGB for "non- WebRGB output" *provided that "you are certain that your workflow won't let anyone convert (or fail to convert) it improperly later."* Has this recommendation not changed in 4 years?

Oliver Desmaison wrote:

I must admit Dan has lost me too in the reply :

"If you are planning to force a file into the deep magentas and cyans

that don't exist in photographs but are achievable on certain

printers, you will get better quality from LAB, but an ultra-wide RGB

may serve."

Yea, lost me too. What "deep magentas and cyans" can be printed on what "certain printers" that "don't exist in photographs?" Dan, what's your definition of a "photograph" and why can't these colors exist in photographs? I'm not familiar with any printer with a gamut that exceeds that of Velvia, Ektachrome, or a digital photograph from a modern camera. The problem is usually quite the opposite. Film and digital captures contain colors that cannot be printed - especially if one uses too small a color space. Lastly, Dan, what is your definition of an "ultra-wide" gamut? DonRGB? ProPhoto? AdobeRGB? Many of the terms in this response (and in the 2-part RGB Working Space post) are very vague, and hence confusing.

On Nov 18, 2006, at 1:56 PM, Dan Margulis wrote:

Re #1. In a perfect world I agree. In the real world, the high

probability that someone will open the file as sRGB far outweighs

any advantage of Adobe RGB. If the image is going to someone known

to understand what an embedded profile is, fine. But as a *general*

recommendation, it is a form of masochism.

This sure sounds to me like Dan is generally *not* recommending anything with a larger gamut than sRGB.

For anyone selling stock photography in this day and age, especially through agencies, it would be a form of financial masochism to attempt to submit/sell images in anything less than AdobeRGB. In a recent survey of stock photographers, over 80% store their master images in AdobeRGB, and 10% in ProPhoto ( 50% used 8-bit TIFs, ~40% used 16-bit TIFs). There is typically no way that a stock photographer will know who is ultimately going to convert the file, or what their qualifications are. I'm usually more concerned when someone asks for "CMYK" or "SWOP" and they have no idea what they're talking about.

The Digital Image Submission Requirements put out by the DISC Alliance (Business Week, Hachette Filipacchi , Newsweek, Time, Kodak, Fuji, etc.) recommend AdobeRGB for all image submissions (http:// www.disc-info.org/specifications/categoryA.asp). Almost all publishers and editors that I deal with strongly prefer AdobeRGB, whether for books or magazines. I know of no image library or agency that specifically recommends sRGB as a file format for anything but web use. In the "real world" of 2006, most photo buyers expect to receive an image in AdobeRGB. So I respectfully disagree with Dan's advice. In general, embed the profile, and tell the recipient, in writing, that the embedded profile is AdobeRGB. If they screw up, they're at fault and they need to learn basic color management. If they state that they need something else, or if you know that they need something else, give it to them.

Adobe RGB is more than sufficient for any current printer in those

areas. Photographs that might require more are readily recognizable

and can be dealt with in ProPhoto on a case-by-case basis without

accepting the colossal penalty of working in ProPhoto on the 99.99%

that don't.

Line one is debatable. Furthermore, how, specifically, do you "recognize" those photos without converting first to ProPhoto to look at the data, and what exactly is the "colossal penalty?" I believe that John Castronovo asked the same question.

I personally don't see the down-side of working in ProPhoto. By doing so, I always know that I have all of the colors that were captured (film or digital) and I don't need to re-scan or re-process images. As pre-press professionals become more comfortable with color management, I envision a day when I can send out images in ProPhoto rather than AdobeRGB, and the pre-press pros will convert the image to their CMYK of choice without problem. And if a printer is using a wider-gamut CMYK inkset like the new TOYO inks, so much the better.

Said manifesto contains the following statement:

"Nobody advocates working in sRGB if you have an extended-gamut

printer; the only question is whether you should use something bigger

(meaning, to most people, Adobe RGB) or whether an ultra-wide RGB is

needed."

In spite of this, you immediately started a thread titled "Is sRGB

the ideal color space for fine-art inkjet printing in 2006?" as if

anybody was arguing that, and you have repeatedly attempted to

demonstrate since then that sRGB is not an adequate space for such

printers, as if anybody had ever said otherwise.

No, this is factually inaccurate. Dan's comment was made on Nov 16, 2006. My post, "Is sRGB the ideal color space...", was *not* in response to that statement; it preceded it by more than 2 weeks. It was made after a post by Murray Dejager on Oct 30, 2006. To get to the subject matter, I don't recall having ever seen Dan step in and advise anyone that if they are printing to an inkjet (an "extended gamut printer"), they should use a profile with a larger gamut than sRGB. I may have missed it. I hope it is now clear that that is his recommendation.

Dan, I'm still not clear what your recommendations are for the following situations. Perhaps you could clear up my confusion as well as any on the List by giving us specific answers.

Dan's recommendations:

1. for the Photoshop Color Settings. Is the answer North American Prepress 2, or something else?

2. for a "default" working space for images whose ultimate use is not known, and for images that will be re-purposed. (This is really the first step in setting up a workflow. Dan used sRGB in Canyon Conundrum "out of convenience," yet he stated he "doesn't endorse it." What's the recommendation?)

3. for the working space for images destined for publication, where submission in RGB is required.

4. for the working space for images destined for fine-art inkjet (or other wide-gamut) printing.

I hope this will give Dan the opportunity to clearly state his recommendations and to clear up any misunderstandings that I may have had and that I may have incorrectly communicated to anyone on this List.

Sincerely,

--Rich Wagner

___________________________________________________________________________

Re: RGB Working Space, Part 2 of 2

Posted by: "Lee Clawson" Lee Clawson double_cloth

Thu Nov 23, 2006 8:49 am (PST)

on 11/22/06 7:30 PM, Dan Margulis wrote:

I am sorry that I am not familiar with the acronym LFP.

Neither was I. Seems to be the new way vendors describe "large format printing".

Lee Clawson

2/\V/\7 Studio

___________________________________________________________________________

Re: Request for Retraction (was The Color of Nature)

Posted by: Dan Margulis

Thu Nov 23, 2006 10:43 am (PST)

Rich Wagner writes,

I have *never* knowingly misstated Dan's or anyone else's position

about *anything* on this list, or anywhere else, and I resent the

accusation that I would do so intentionally. It *is* certainly

possible that I've misunderstood Dan's position or recommendations on

many different issues, as I find much of his writing vague and

without well-defined terms.

This is a second, and final, demand that you immediately acknowledge that I have never recommended using sRGB as a workflow for inkjet printers. I previously asked that you do so, provided you with unambiguous quotations as to what my position is, and you have responded with a mealy-mouthed repetition of the same expressions of doubt and implications that I *do* advocate such a workflow.

In Canyon Conundrum, Dan uses sRGB throughout

and there is no discussion in that book of using a wider color space

for "non-Web RGB." How is a reader to know that back in 2002, in a

different book, Dan made the recommendation to use AdobeRGB for "non-

WebRGB output"

Knowing misstatement. You know, because I posted you the exact quotes, that there is no recommendation OF ANY KIND with regard to either RGB or CMYK, because it is a book about LAB. You know, because I posted two quotes, that I specifically said that the use of sRGB and SWOP v2 as defaults is ONLY because they are majority settings, that no endorsement should be implied and that in fact I did not approve of them. You know, because you intentionally deleted a book sentence saying that I did not endorse sRGB, and then posted the very next sentence to this list as evidence that I *did* endorse sRGB.

On Nov 18, 2006, at 1:56 PM, Dan Margulis wrote:

Re #1. In a perfect world I agree. In the real world, the high

probability that someone will open the file as sRGB far outweighs

any advantage of Adobe RGB. If the image is going to someone known

to understand what an embedded profile is, fine. But as a *general*

recommendation, it is a form of masochism.

This sure sounds to me like Dan is generally *not* recommending

anything with a larger gamut than sRGB.

Knowing misstatement. You cannot possibly believe that a recommendation not to give Adobe RGB to strangers means that you shouldn't use it yourself.

The archives of this list are littered with examples of how people's jobs were ruined because Adobe RGB was handed out to strangers who did not understand that they needed to honor embedded profiles. We saw another example only two weeks ago. A non-masochist, therefore, makes sure that such files don't fall into the hands of strangers. Many non-masochists, myself included, do not work in sRGB themselves, but, in the interest of avoiding disaster, convert files either to LAB or to sRGB before giving them to strangers.

I hope this will give Dan the opportunity to clearly state his

recommendations and to clear up any misunderstandings that I may have

had and that I may have incorrectly communicated to anyone on this List.

No, you understand the recommendations perfectly well already. Offering opinions is one thing, deliberately misstating an opponent's position after you have repeatedly been asked to desist is another.

If you wish to deal with the list in an honest fashion, then kindly issue a statement something along these lines. "I may have been confused about this in the past, but it has now been made clear to me that Dan Margulis does not now and never has recommended sRGB as a working space for inkjet output."

If you can't see your way clear to posting something like that, I'd take that as a pretty good indication that shortly we will see you telling multiple other lists that sRGB is a terrible working space for inkjet printing no matter how much Dan Margulis attempts to convince us otherwise, etc., etc. We've seen that sort of thing before from others, and nobody can prevent you from doing it, too. But it won't be tolerated here.

Dan Margulis

___________________________________________________________________________

Re: Request for Retraction (was The Color of Nature)

Posted by: Richard Wagner

Thu Nov 23, 2006 3:16 pm (PST)

On Nov 23, 2006, at 9:39 AM, Dan Margulis wrote:

This is a second, and final, demand that you immediately acknowledge that I

have never recommended using sRGB as a workflow for inkjet printers.

Dan, the only way I could make this statement is to know everything you have ever said or written. That's impossible. If you say you haven't, that's good enough for me.

In Canyon Conundrum, Dan uses sRGB throughout

and there is no discussion in that book of using a wider color space

for "non-Web RGB." How is a reader to know that back in 2002, in a

different book, Dan made the recommendation to use AdobeRGB for "non-

WebRGB output"

Knowing misstatement.

What exactly is misstated? That you used sRGB throughout the Lab book? That you don't discuss using a wider color space than sRGB for "non-Web RGB" in the Lab book? That you made a previous recommendation in 2002 in your other book? Those are simple statements of fact.

You know, because I posted you the exact quotes, that there is no

recommendation OF ANY KIND with regard to either RGB or CMYK,

because it is a book about LAB.

Fine, there is no recommendation for output in the book. That's my point - you did not make a recommendation, so the user needs to make assumptions or guess what your recommendation would be. The whole purpose of color correction is to eventually output the image in some way, so if you would do things differently depending on the output, I would think that would be important to mention. If I were to assume that you would do things the same way, regardless of where the ultimate destination will be, I'd be wrong. But how am I supposed to know that from reading the book?

Just recently you wrote, "However, let me say that my correction philosophy depends very little on the output device. Each one has a different set of achievable numbers, but the basic principles remain the same whether preparing a file for newsprint or for a 12-color inkjet." What is implied, but not explicitly stated, is that you need different working spaces to "achieve the numbers." How is a reader of Canyon Conundrum supposed to figure that out? Divine inspiration?

You know, because I posted two quotes, that I specifically said

that the use of sRGB and SWOP v2 as defaults is ONLY because they

are majority settings, that no endorsement should be implied and

that in fact I did not approve of them. You know, because you

intentionally deleted a book sentence saying that I did not endorse

sRGB, and then posted the very next sentence to this list as

evidence that I *did* endorse sRGB.

Dan, I've been saying that I'm not sure what you endorse, because I have not seen specific recommendations or endorsements from you. You use one RGB color space exclusively, yet you don't endorse it and you don't recommend anything else, and you give no guidance on selecting a color space. What is one supposed to infer?

Knowing misstatement. You cannot possibly believe that a

recommendation not to give Adobe RGB to strangers means that you

shouldn't use it yourself.

But the primary reason I prepare images is not for "myself," but for someone else. It still sound like you are saying that if the image is going to someone else, it should not be in AdobeRGB. So what color space should it be in?

I hope this will give Dan the opportunity to clearly state his

recommendations and to clear up any misunderstandings that I may have

had and that I may have incorrectly communicated to anyone on this

List.

No, you understand the recommendations perfectly well already.

Actually, Dan, I don't. I listed several areas where I don't know what you recommend, and you still have not given simple, straight- forward answers of what you DO recommend. A lot of DON'Ts are not equal to a DO.

I'm trying very hard to give you the opportunity to state in black and white what your recommendations are, so that they are clear to everyone and can be referenced here on this List.

If you wish to deal with the list in an honest fashion, then kindly issue a

statement something along these lines. "I may have been confused

about this in the past, but it has now been made clear to me that

Dan Margulis does not now and never has recommended sRGB as a

working space for inkjet output."

Fine. That's easy. I may have been confused about this in the past, but it has now been made clear to me that Dan Margulis does not now and never has recommended sRGB as a working space for inkjet output. Everyone got this? That question is settled.

Unfortunately, I still do not know the following, because you have so far refused to answer:

1. Dan's recommendations for the Photoshop Color Settings.

2. Dan's recommendations for a "default" working space for images whose ultimate use is not known.

3. Dan's recommendations for the color space for images that will be re-purposed by a client.

4. Dan's recommendations for the working space for images destined for publication, where submission in RGB is required.

These are issues that photographers must deal with daily, and specific recommendations would be useful.

You also did not respond to my question of whether or not your recommendation from 2004 (quoted below) remains in the 5th edition of your book. Does it?

If you can't see your way clear to posting something like that, I'd take that

as a pretty good indication that shortly we will see you telling multiple

other lists that sRGB is a terrible working space for inkjet printing no matter

how much Dan Margulis attempts to convince us otherwise, etc., etc.

You're paranoid. See above. You have given an unambiguous answer as to what you do NOT recommend, and that matter is settled as far as I am concerned.

We've seen that sort of thing before from others, and nobody can

prevent you from doing it, too. But it won't be tolerated here.

Dan, all have asked for are your recommendations, so that they are clear to everyone, and so that you will not be misinterpreted by me or anyone else. As I stated previously, I have no desire to misstate your position on anything, here or anywhere else, so I would request that you refrain from making such unsubstantiated accusations and character attacks. Let's stick to Color Theory.

--Rich Wagner

___________________________________________________________________________

Re: Request for Retraction (was The Color of Nature)

Posted by: "Stephen Best"

Thu Nov 23, 2006 5:29 pm (PST)

--- Richard Wagner wrote:

Fine, there is no recommendation for output in the book. That's my

point - you did not make a recommendation, so the user needs to make

assumptions or guess what your recommendation would be. The whole

purpose of color correction is to eventually output the image in some

way, so if you would do things differently depending on the output, I

would think that would be important to mention. If I were to assume

that you would do things the same way, regardless of where the

ultimate destination will be, I'd be wrong. But how am I supposed to

know that from reading the book?

One would assume that if you're able to wade through the concepts and implications of editing in LAB, you're also capable on figuring out what working space to use for your own purposes, what to use for Color Settings etc. Really, the issue is trivial.

At heart though, I suspect the discord is between those for whom overall gamut is a major preoccupation, and Dan's approach that addresses distinction and variability of colours within the gamut (any gamut). The latter is what interests me more.

Stephen Best

Macquarie Editions

___________________________________________________________________________

Re: Request for Retraction (was The Color of Nature)

Posted by: "MARK SEGAL" Mark Segal markds0

Thu Nov 23, 2006 5:38 pm (PST)

Richard,

What would happen if there were no such thing as pat recommendations for setting each of these four variables? What if the answers varied according to the image and the purpose? If the answer to these "what ifs" were "yes, that's possible", you would here be asking for the impossible. That's point number one.

A corollary to point number one is that under these circumstances the best Dan could do is give guidance in general terms as to the settings that based on his experience seem to be most appropriate for certain generic kinds of image/destination scenarios, while not boxing himself into corners.

Point number two is that while I have a great deal of respect for Dan Margulis' experience and ingenuity in this field, I also have a mind of my own, and I'm willing to discover these "truths" by trying different things for different images, printing the results and asking my wife and myself which looks best and why. If the findings were to coincide with Dan's guidelines, that is positive, but not essential reinforcement. It just isn't necessary or even useful to set-up strawmen and knock them down in order to improve one's skills in digital imaging.

Now I suggest we all move on.

Mark Segal

___________________________________________________________________________

Re: Request for Retraction (was The Color of Nature)

Posted by: Richard Wagner

Fri Nov 24, 2006 12:07 am (PST)

On Nov 23, 2006, at 5:21 PM, MARK SEGAL wrote:

Now I suggest we all move on.

I'm in complete agreement.

--Rich Wagner

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Iliah Borg"

Thu Nov 23, 2006 12:01 pm (PST)

Dear Stephen,

This begs for some questions.

How do ALR/ACR convert to the colour space with those primaries, is it using a matrix transform from supposed camera "primaries"? How wide is that "source camera space" then?

More important, is it a fact that ProPhoto is everywhere larger then any given camera "gamut"? (Not what I see, as D2X response seems wider in some zones starting at L*=30 and all the way up to L*=100; reaching a=12 b=-93 at L*=50; a=0 b=-50 at L*=75 etc.)

Is it a known and proven fact that with methodic used in ALR/ACR this transform to "internal colour space" is necessary at all? And if it is, why not Lab?

I'm trying to say once more that choice of ProPhoto primaries for "internal working space" have its implications and may complicate workflow unnecessary.

There is no question at all why raw pre-processing like eV compensation or WB are done nicely in linear colour space. Do other moves benefit from linear space IMHO is not so obvious.

Best regards,

Iliah Borg

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Thu Nov 23, 2006 3:16 pm (PST)

On 11/23/06 12:01 PM, "Iliah Borg" wrote:

How do ALR/ACR convert to the colour space with those primaries, is it

using a matrix transform from supposed camera "primaries"? How wide is

that "source camera space" then?

I suspect only Thomas Knoll could answer that. You could ask in one of the Adobe Forums, he©ˆs usually responsive to such questions. I know he©ˆs building his own Œprofiles©ˆ when he gets camera samples and these are not ICC profiles. The so called profiles are built using software of his design.

More important, is it a fact that ProPhoto is everywhere larger then

any given camera "gamut"?

My own tests which are admittedly not (color) scientific was shooting a ColorChecker DC, exporting the linear Œunprocessed©ˆ (as little processing as possible using Raw Developer) and building an ICC profile of a Canon Rebel showed it©ˆs gamut exceed Adobe RGB (1998) in greens by a substantial amount along with other colors. But I©ˆm not an advocate of profiling cameras and realize the gamut of the target plays a significant role and doesn©ˆt define the possible color mixing functions of the device. But based on rendered images and this profile, I©ˆm pretty sure Adobe RGB (1998) isn©ˆt going to cut it as an internal color space due to it©ˆs small gamut size. ProPhoto RGB is large enough, at least with the images I©ˆve plotted and this so called linear, minimally processed image.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Andre Dumas

Fri Nov 24, 2006 12:06 am (PST)

Thanks Bob,

I guess I didn't follow the discussion close enough and anyway I should have realized all this from the start since the point in this discussion is "wide-gamut workspace/ wide-gamut-printer output", and I should have realized that a profile is *the* key element in any printing process.

So now after reading some fifty odd posts about ProPhoto RGB and wide gamut output my enthusiasm for it has suddenly shrunk substantially. So, ProPhoto RGB is "nice" if you have a wide gamut printer *and* professional profile making software, and I probably a rip like ImagePrint. But what about us, the plebes, there is not much point in using it, with our ridiculous equipment ProPhoto prints turns out to look just like good old sRGB's.

I've been spending 2 hours every day reading and printing posts, underlining and highlighting key sentences ... just to find this out now! I'm slow but I eventually get there ... I think, or did I miss something again?

But, seriously I agree that a wide-gamut working space has many advantages and that my time wasn't really wasted BUT for the time being I'll stick with Lee Varis's suggestions, it's much closer to my reality.

André Dumas

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High-resolution, wide-gamut test images

Posted by: Richard Wagner

Thu Nov 23, 2006 3:22 pm (PST)

Dear List,

To change the subject and try to provide something of benefit to everyone, here is a file containing 15 high-resolution, wide-gamut test images in 8-bit Lab, along with 4 other grayscale/calibration targets. These are not my images, but rather images that have been provided to the community by Bill Atkinson for evaluation of profiles and printers. I have used these images for testing new inkjet papers, and I had forgotten the source of the original images, as there was no metadata in the file. In browsing Bill's web site recently, I remade the connection.

The gamut of these images is huge!!! I am fairly certain that most of the photos were made from high-res scans of large-format film.

The file is 5520 x 6960 pixels, in 8-bit Lab, and it weighs in at 39.2 MB. I have embedded a link back to Bill Atkinson's site in the Lab file metadata.

Here's a small JPG in sRGB so that you can see what it looks like. (Watch for broken links)

http: //www.wildnaturephotos.com/Private/Lab-Test-Page/Lab-Test-Page.jpg

and the high-res file in Lab:

http: //www.wildnaturephotos.com/Private/Lab-Test-Page/Lab-Test-Page.tif

There are other images included with the Profile Test Images bundle (52 MB) that can be downloaded directly from Bill Atkinson's site here:

http://homepage.mac.com/billatkinson/FileSharing2.html

and more specifically here:

http: //homepage.mac.com/WebObjects/FileSharing.woa/wa/Profile_Test_Images.zip.zip?a= downloadFile&user=billatkinson&path= /Public/Profile%20Test%20Images.zip

These images are great for evaluation of profiles and printing conditions, as their gamut is wider than that of all printer profiles that I know of and they will pull as much color as possible out of your printer.

Have fun, and Happy Turkey Day to those who celebrate it.

Best,

Rich Wagner

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Re: High-resolution, wide-gamut test images

Posted by: "MARK SEGAL"

Thu Nov 23, 2006 5:33 pm (PST)

Richard,

Thanks for the information. This could be useful

Mark Segal

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Re: High-resolution, wide-gamut test images

Posted by: "Ric Cohn"

Fri Nov 24, 2006 12:06 am (PST)

Richard,

Thanks for posting this. I spent a good deal of time using it to explore some of the issues we've been discussing.

I was interested in looking at the brightest colored photographs in the Lab Test Page (the middle third) and ignored the non-photographic targets. I looked at the full size image on my Sony Artisan Profiled calibrated to the "CRSFineArt" target color space. For printing, I reduced this area to approximately 8" x 5" to fit on a 1/2 sheet of my paper. It includes the lower part of the Kids Faces down to the top of the Color Bars. Maybe I should have printed them out bigger, but I think I can see enough. I ended up using a loop to look at the prints. If someone sees something very different from a particular image printed at full size I'd be willing to look again.

I soft proofed and printed (photo gloss paper, custom profile, Canon i9900 printer) from: 1. Lab, 2. sRGB, 3. AdobeRGB, 4. ProPhotoRGB, 5. L*Star RGB, 6. Beta RGB. I first printed the original Lab file using both Relative and Perceptual. I thought the Perceptual image looked very slightly nicer, so I used this for all. I'll give my observations and ask other's what they conclude. Here's what I saw.

1. There were *no* areas of these highly colored actual photographs that showed nearly the same severity of problems that your Construction Paper image showed with any color space I looked at.

2. The differences in the soft proof were more obvious than in the actual prints-- especially for sRGB where the soft proof looked really bad and the print looked just slightly less saturated in a few areas. The out of focus Strawberries in particular appear to lose detail in the sRGB, AdobeRGB and L*Star RGB soft proofs, but I didn't see *any* difference in the prints.

3. I could find only one area of one image where my Monitor's view of the images changed when I switched from Lab to the various color spaces . This was for *ProPhotoRGB* (the sky between the Red Rocks). This difference translated into a difference in the Soft Proof and I think there is a slight difference in the print as well.

4. There are areas where my *softproof* to my Printer Profile changes subtly, but significantly, from the original Lab to one or another of the RGB spaces in ways that I would not expect and which did not show the same way in the prints. I don't know if it's a limitation of the proofing part of some profiles or of my printer profile or my monitor profile.

Some areas where I saw these differences were in the brightest red leaves of the Fall Foliage (the reddest leaves in shadow previewed lighter in sRGB in particular), the darkest out of focus green branches of the Yellow Flowers (sRGB actually looked better because the darkest greens previewed lighter and greener), The out of focus part of the Strawberries (both sRGB and AdobeRGB look like they're going to go to red blobs), and the sky seen through the Red Hills (ProPhoto goes purple, although this one may be real since this area also changed when I converted from Lab to ProPhoto).

5. Besides the sky mentioned above for ProPhotoRGB (which appears to be due to a difference in rendering when converted from Lab), the only *print* I could see a difference in was the sRGB. This print was very slightly less colorful. This is particularly visible in the dark green behind the Pink Rose and in the Tropical Greens. I couldn't tell any of the other prints apart including the one from AdobeRGB (I wrote info on the back of the prints).

6. After looking at the soft proofs, the only area I looked at and saw a potential problem with color blocking up was the out of focus part of the Strawberries which looked like it was going to lose detail in the sRGB and AdobeRGB print previews. In the actual prints I didn't see any difference in detail anywhere.

From this I conclude:

A. The original files are of high quality.

B. An sRGB print of these subjects still looks good, but a little less colorful.

C. ProPhotoRGB can show changes in color/tone when converted from the original Lab data.

D. AdobeRGB is large enough for any of these images.

E. There are deficiencies in my proofing preview which make it impossible to trust it completely in evaluating subtle differences between color spaces.

F. Although all the images print fine, in looking at the Channels, I believe making major edits to the most colorful of these files would definitely be easier in a space larger than sRGB and probably larger than AdobeRGB, because the channels maintain more detail.

I hope this is clear enough for others to follow. What do other's conclude? If anyone looks at this image file in the same way please let us know if your set up shows the same/similar issues.

Ric Cohn

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Dan Margulis

Fri Nov 24, 2006 8:29 am (PST)

Matthew writes,

I've never heard Dan say this, but I do believe that his writings

indicate that he feels a professional should be able to get a great

looking print no matter what color space is chosen. A real

professional in any field should be able to work within whatever

limitations exist and actually produce a competitive, if not superior

result, to someone working with better equipment but less skill.

November is the month in which I teach advanced courses, open only to those who have already taken the three-day Applied Color Theory courses. The people who take these advanced courses are quite good at what they do.

The format is that everyone works on the same images, and then we compare results. Also, I show some of the better results from previous years. Late in the first day, there's an amusing wrinkle: people have to color-correct three images on a monitor set to grayscale--no view of the color at all.

This has always been a feature of the advanced class, because it comes as a shock to many students that such an exercise is even possible. Some find it an epiphany while others think it obvious enough to be a waste of time.

This year, there was a new wrinkle. Before comparing the three sets of images, I explained to the class that in the previous year the class had worked on two of the three images with the same disadvantage--namely, a monitor set to grayscale. In the third, they had worked normally with a color monitor. I asked this year's classes, after seeing all three images, and a couple of the best efforts from last year's classes on each, to identify which one had been worked on in color.

One class mostly got it right. The other, everyone who guessed was wrong. Taken as a whole, the guesses were random-generator--meaning that the students could not distinguish which images had been worked on black and white monitors last year, as opposed to on color monitors.

Working on a black and white monitor is an adverse condition, and it can be coped with fairly easily; a qualified person easily gets better color on such a monitor than a less-skilled person does with the most expensive equipment in the world. Nevertheless, nobody works on a black and white monitor by choice.

We aren't always so lucky as to be able to choose. Working with a prescreened original is an adverse condition. Preparing for a newspaper is an adverse condition. Dealing with a difficult client is an adverse condition; an underexposed original is an adverse condition; not having as much time to work on an image as we should is an adverse condition; having to deal with an incompetent printer or photo lab is an adverse condition, and on and on.

Everybody in this field deals with adverse conditions, and the test is how well we cope with them. Learning how to do so is often critical because it shows us how to deal with situations where there is no adverse condition--or rather, where most non-experts would *notice* no adverse condition, and not realize that action was necessary.

Dan Margulis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Andre Dumas

Fri Nov 24, 2006 8:32 am (PST)

Dear Lee (Varis),

You said (in a post that I can no longer find): "I'd rather save ProPhoto for those rare times when I know I'm going to be working with extremely saturated colors that are IMPORTANT to the image."

Lee, I photograph a lot of flowers (close-ups) in full sun and these are usually "extremely saturated" and I've found that when I use ProPhoto RGB, many times, important details are blown out. Hasn't this been your experience also?

You talk about wanting to work on an image and see *all of it* on your monitor, this is sooo logical and much simpler than sampling individual areas in a photo (particularly when you have to correct 300 images before 5:00.) But then what about prints, you say: "you have to make adjustments after you've seen a print." do you feel that a print is really a "standard" that can be used to judge the quality of one's work? What about if you had a better printer or a better profile?

Although I have a fairly wide gamut printer I may no longer judge my work by looking at one of my print, you see my profiling software is the lowly Monaco EasyColor. What is yours?

Lee Varis wrote: "NOBODY is arguing that ProPhoto shouldn't be used as a container of full gamut imagery BUT if it is your intention to EDIT the file after capture to achieve a result that alters color relationships in any creative way it just makes a lot more sense to be able to see ALL the subtle color relationships you are altering before you make a print – otherwise we're back in the pre-color management days where you have to make adjustments after you've seen a print."

Thanks,

André Dumas

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Richard Wagner

Fri Nov 24, 2006 8:32 am (PST)

On Nov 23, 2006, at 8:04 PM, colorman042000 wrote:

But what about us, the plebes, there is not much point

in using it, with our ridiculous equipment ProPhoto prints turns out

to look just like good old sRGB's.

Andre,

I sure wouldn't go that far. Maybe like AdobeRGB, but as you hopefully noticed, Dan does not recommend printing from sRGB to an inkjet, particularly if you are doing the printing yourself and not giving your image to someone else to print for you. Inkjets clearly have a gamut wider than sRGB.

To quote the pertinent section of Professional Photoshop 4E (2002),

p. 270: "The recommendations for the practical person, therefore,

are as follows:...[for] Work primarily aimed at non-Web RGB: If you

are certain that your workflow won't let anyone convert (or fail to

convert) it improperly later, use Adobe RGB."

I hope by now this is not controversial.

--Rich Wagner

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Veli Izzet Cigirgan"

Fri Nov 24, 2006 8:44 am (PST)

Hi,

In that case you do not even need a color monitor, you can do color correction by numbers only on a monochrome monitor (if such a beast still exist).

Is it really possible to KNOW all the output colors without seeing them, just by numbers?

Is this not a way of saying profiling the monitor is really not worth

anything?

Regards,

Veli I. Cigirgan

___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Lee Clawson"

Fri Nov 24, 2006 9:54 am (PST)

Veli,

Personally I would say no. Especially if you need to "know all the output colors".

But years back the guy who kept our drum scanner in repair was color blind. He looked at the on-the-fly converted CMYK color readouts on the scanners keyboard and knew what made sense. Within his limits with "greens" a highly developed skill at capturing a great tonal range made it possible to make scans as well as ours.

By looking at color with a sense of what was a reasonable CMYK mix of color (that I envied) made it possible for him to work with color by the numbers without knowing all of them. I'd hate to use a grayscale monitor but (with an original reference) it wouldn't be an impossible task.

When it came to repairs on color coded wiring harnesses we worked differently. Lee Clawson 2/\V/\7 Studio ___________________________________________________________________________

Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Jim Rich"

Fri Nov 24, 2006 12:24 pm (PST)

On 11/24/06 5:03 AM, "Veli Izzet Cigirgan" wrote:

Is it really possible to KNOW all the output colors without seeing them,

just by numbers?

Not all, but a lot of them. But there is more.....

Dan's class sounds interesting. And while I don't know the details of what Dan is covering in this class, as someone who has created a few color separations and toned a few grayscale images over the last few years, you should be aware that there is more to going-by-the-numbers and using grayscale channels to color correct images.

For example, one issue that was not mentioned was getting visual feedback from say hardcopy color proofs or a well-calibrated color monitor. This is done a number of ways using color references and by knowing the target "numbers" that created neutral gray, highlight, midtones shadows and selective color areas within the color reproduction of reference images.

In learning how to go-by-the-numbers, you can gain experience by seeing (and perhaps remember) the cause-and effect-relationships of using the numbers via changing a grayscale channel to create a certain color appearance. This is the way scanner operators worked until desktop publishing and soft-proofing started working. Even today, the better color operators use both methods of going-by-the-numbers and soft-proofing.

Is this not a way of saying profiling the monitor is really not worth

anything?

It was proven a long time ago, that (1) if you know how to go-by-the-numbers you can control and create good color corrections. And (2) if you use a well calibrated monitor that has a close visual appearance to the hardcopy proof, it is then possible to use both methods to your advantage. In that case, a seasoned operator works the most efficient and cost effective way to optimize an image.

Actually, I was involved with one the first cases of proving the effectiveness of soft-proofing for DTP in1992. It was verified and then reported on that going-by-the-numbers and using a calibrated monitor, (to look like a hard copy proof), was the most effective way to color correct images on the desktop.

And of course it is important to have control over the viewing environment. This often means curtains on the windows and using a light box with a dimmer next to your monitor. If you don't have control over the viewing environment, then optimizing an image becomes a trade-off of making extra prints. Then relying on going-by-the-numbers can be essential.

To answer your question, accurate soft-proofing becomes a bottom line issue this means making a good monitor profile. This approach saves a company money from extra proofs being made.

Jim Rich

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: “Andrew Rodney”

Fri Nov 24, 2006 1:36 pm (PST)

On 11/24/06 9:16 AM, "Lee Clawson" wrote:

Personally I would say no. Especially if you need to "know all the output

colors".

Piece of cake. That©ˆs all an output profile does. It defines the color space and hence color numbers of an output device. If you have a good profile, you have all the numbers supplied by Photoshop. How useful those numbers are is another issue.

Andrew Rodney

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Lee Varis"

Fri Nov 24, 2006 6:54 pm (PST)

On Nov 24, 2006, at 7:46 AM, colorman042000 wrote:

Lee, I photograph a lot of flowers (close-ups) in full sun and these

are usually "extremely saturated" and I've found that when I use

ProPhoto RGB, many times, important details are blown out. Hasn't

this been your experience also?

It depends - it may just be "blown out" on the monitor, or it may in fact be unprintable. Its hard to tell until you make a print if you're in ProPhoto. I will mostly process into ProPhoto to gain access to better grayscale channel information that I can use in luminosity blends that can strengthen separation of values in saturated areas of color. For color I tend to go with Adobe RGB simply because I can see that color to make informed decisions with regards to color and tone. I find the pursuit of saturated color to be mostly more trouble than its worth - color relationships and the value structure of the image are much more important!

You talk about wanting to work on an image and see *all of it* on

your monitor, this is sooo logical and much simpler than sampling

individual areas in a photo (particularly when you have to correct

300 images before 5:00.) But then what about prints, you say: "you

have to make adjustments after you've seen a print." do you feel

that a print is really a "standard" that can be used to judge the

quality of one's work? What about if you had a better printer or a

better profile?

I generally make the best looking RGB file I can based on the monitor and numerical aim points ( like white, black, neutral – cmy values for skin tones, etc...) and I'm rarely disappointed by the print. For the most part I can make very satisfying prints without accessing the small extra gamut of Epson inkjet printers. When I revisit images that were printed years ago I have no trouble making better prints with better printers without jumping through hoops. Sometimes the print might surprise me and I'll make additional adjustments but most of the time not. As far as a standard to judge one's work - if the print is the final product then that IS the standard, if not, then not!

Although I have a fairly wide gamut printer I may no longer judge my

work by looking at one of my print, you see my profiling software is

the lowly Monaco EasyColor. What is yours?

I use the Pulse Color Elite system... a Monaco-x-Right product and I've been very happy with it.

regards,

Lee Varis

President, LADIG

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: Dan Margulis

Fri Nov 24, 2006 8:32 am (PST)

Brian Pylant writes,

But I stand by my statement: regardless of how you feel about Dan's work or

writing, that was an absolutely AWFUL thing to have said about another

person, that it would be "too good" to see harm come to him.

True enough, but it's time to move on. An unqualified apology was issued, and, since I never responded, let me now note for the record that I accept it.

No, I don't think Dan is always right. Dan is not always lovable.

Shh!! There are a lot of members of this list who aren't aware of this! Please don't spread this slander around!

Dan Margulis

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Re: [Off-List] RGB Working Space, Part 2 of 2

Posted by: "Lee Clawson"

Fri Nov 24, 2006 9:55 am (PST)

on 11/24/06 10:20 AM, Dan Margulis at Dan Margulis wrote:

True enough, but it's time to move on. An unqualified apology was issued, and,

since I never responded, let me now note for the record that I accept it.

Dan,

Thanks.

Lee Clawson

2/\V/\7 Studio

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Re: High-resolution, wide-gamut test images

Posted by: Richard Wagner

Fri Nov 24, 2006 8:32 am (PST)

Ric,

Thanks for bringing us back to color theory. Could you send me your printer profile so that I can compare it to what I'm familiar with, as well as to some standard working spaces?

Also, perhaps you could list the col,row numbers of the images that you used, or name them.

I'm not sure that reducing these images down as far as you did will allow valid comparisons. If I get a chance today, I'll try to crop 100% sections of several images and compare. I have a print on 24x30 Luster printed from ImagePrint that I use for comparison, as well as smaller prints on multiple papers.

Thanks again,

--Rich

___________________________________________________________________________

Re: High-resolution, wide-gamut test images

Posted by: "Ric Cohn"

Fri Nov 24, 2006 6:14 pm (PST)

Sure, I can describe them by column numbers. I tried to be descriptive in my last message, hopefully this will give us a common set of names. BTW, the link to the Tif on your server didn't work. I downloaded "Lab Test Page.tif" from your Bill Atkinson's page link: http: //homepage.mac.com/billatkinson/FileSharing2.html. The download is labeled "Profile Test Images".

From top to bottom (ignoring the B&W Grad at the bottom):

Column 1: 1. Fuji Test image. 2. Tropical Greens. 3. Fall Folliage (Red Leaves). 4. Ocean Sunset.

Column 2: 1. Pastel soaps. 2. Pink Rose. 3. Yellow Flowers. 4. B&W Gradient 5. Color Gradients.

Column 3: 1. Electonics. 2. Strawberries. 3. Lava Flow?? 4. B&W Desert. 5. Color Bars.

Column 4: 1. PDI Test Image. 2. Yellow Leaves (Fall). 3. Red Rocks and Sky. 4. Reflection in Sand

As I said, I was only interested in the brightest actual photographs, so I trimmed off most of the top row and the bottom 2 rows and kept the full width. My crop included just the bottom of the "Fuji Test Image" which gives part of the kids faces in the "PDI Test Image" . I cropped down a little below the sun in "Ocean Sunset", which also gave me the top of the "Color Bars".

I'll send you the profile off-list.

Ric Cohn

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Re: Iris printer (was Request for Retraction)

Posted by: Dan Margulis

Sat Nov 25, 2006 6:45 am (PST)

Greg Welch writes,

A week or so back, I made it clear to the list that I use sRGB in my

workflow. I use Iris 3047 printers in the reproduction of artwork. Of course we use

them to create original work ie. photography and digital artwork.

OK, I stand corrected, but I think Iris printers are not typical of the class being discussed in the thread, being that their preferred input is CMYK.

If you have access to the actual ink values, and are interested in achieving optimal saturated colors, then you should work in the final output space, as you are doing. Maneuvers in RGB, other than channel blends, are of limited use in this workflow.

By correcting in cmyk I can do very cool and effective corrections. Perhaps

if I could afford an Eizo and all new profiling software it might, be worth

it to do aRGB or Pro rgb. If I was using an Epson it would be a different story

for me.

Yes. If you can't access the inks directly, you're at the mercy of the machine's ink generation, and you have to give RGB. But I agree, properly treated, Iris printers can yield excellent results.

Dan Margulis

___________________________________________________________________________

ProPhoto as default

Posted by: "Lee Varis"

Sat Nov 25, 2006 8:37 am (PST)

Hi all...

One last very long post!

This will be my last post on this subject as I see this as receiving entirely too much emphasis on this discussion list and I think we should move on to other things.

There continues to be some confusion over what each side of this debate is arguing for. I personally don't see any argument over the position statements if we examine them in isolation.

Position One: ProPhoto is the best workspace to process RAW camera files into to insure that you can encode the entire color gamut of any given image and also insure that you can hit colors that a printer is capable of but that may be outside of the monitors color gamut.

I have absolutely no argument with this statement. Really, I don't.

Position two: ProPhoto has some disadvantages as an editing space because subtle adjustments using Photoshop controls have a more drastic impact on color relationships that are in-gamut for the monitor in such a wide gamut color space. Given that most of the time, important color relationships are in-gamut for most photographic images, a more color-constrained workspace may be more desirable as a default editing workspace.

If you understand the position two statement, I thinks its hard to argue with. Position one is NOT an argument against position two. These are two different issues. For many users the advantage of ProPhoto as a color encoding space far outweigh any considerations for editing space. Especially if you routinely do all your "edits" in the RAW file converter. Great - no argument from me here.

It just gets extremely tedious to argue against the benefits of editing in a more constrained colorspace by reiterating a position that addresses color encoding using a RAW file processor!

Here is a web page that illustrates the difference between the same edit in ProPhoto vs AdobeRGB:

http: //www.varis.com/ColorTheory/ProPhoto_vs_sRGB_edits.html

In a previous rather long post, I stated that photographers as a group seem to be more comfortable relating input directly to output and are willing to give up control at intermediate stages of the image creation process, at least until they've seen a print. There are historical precedents for this and it seems that many still prefer to work this way - I call these artists "picture takers" - for this group most of the creative process "stops" after the shutter is released.

Another group of artists are more interested in moulding the captured image into something else – forcing it to fit their artistic vision. Rather than looking for something in the external world that communicates their way of seeing they force and distort the external world to fit their internal vision – I call these "picture makers" – for this group most of the creative process "starts" after the shutter is released.

Of course there is not such a hard line between groups and most artists fall somewhere between these two extremes. Often, graphic designers and prepress professionals fall into the "picture makers" category by default because they are mostly working with other people's images and trying to serve the artistic vision of third parties (i.e. clients). The main emphasis of the Applied Color Theory list serve seems to me to be on practical commercial imaging (I could be wrong) as most of the users here are involved with imaging to generate income in a commercial context. Though things are changing, the vast majority of images that are being used today are in need of adjustment after or in spite of any RAW file processing and the vast majority of such commercial images tend to be less than ideal for their intended application. You would have to spend some time in a commercial environment to appreciate this but this really is an indisputable fact of life for many of the people participating on this list.

The question of what workspace to use as a default has a completely different meaning when considered in this context. Hopefully we can agree that the choice of "default" editing space "may" end up being different depending on the context regardless of whether the user is advanced or unskilled! For very practical reasons, considering the vast majority of images that need to be used for the vast majority of commercial uses for the vast majority of output devices that the vast majority of viewers are likely to encounter in the vast majority of social settings (this is a lot of images)– sRGB might, in fact, be a good default editing space. I think this is a perfectly reasonable point of view.

I think its perfectly unreasonable to assume that ProPhoto RGB is the best default editing workspace all the time because you have personally never seen an instance where simple edits harmed an image processed into ProPhoto RGB from a RAW camera file! The only thing one can say about the best way to do something is to say, "this works for me!" The "best" way to do anything is going to vary quite a bit from one person to another but it is quite a different thing than speculating about the merits of a default workspace for the majority of professional users. In fact I believe that a default workspace may also be quite variable depending on the context so it may be impossible to actually recommend a default without asking a lot of questions about common workflow practices.

I am currently directing digital services for a high-end commercial photo lab in Los Angeles. This lab (the Icon, inconla.com) does RAW file processing, large format prints of all kinds, web galleries and retouching for entertainment industry clients as well as fashion, advertising and editorial photographers and international clients. 90% of the imagery that comes into the lab is in Adobe RGB, the remaining 10% is untagged. I have yet to see anything that comes into the lab tagged with ProPhoto! How could I recommend any other default than Adobe RGB for the lab! Clients generally expect the files to be in Adobe RGB and in EVERY case involving an output they want the print to MATCH THE MONITOR! Nobody, AFAIK, has ever asked for a color that they can't see on the monitor. So, in my particular context, it makes no sense to "default" to anything else but Adobe RGB! I suspect that most customers of our lab would be well served with sRGB because most don't use high-end monitors to view their images but Adobe RGB has become universally accepted among almost every customer as the "standard" so this is our default. I don't see this changing any time soon.

This is all a rather long winded way of saying I use Adobe RGB, your mileage will vary! I'm perfectly willing to accept that for Andrew Rodney, ProPhoto is a great default workspace but that doesn't mean I would necessarily recommend it for everyone as I wouldn't necessarily recommend Adobe RGB for everyone. sRGB is probably more appropriate for the average user because their reference "standard" is the monitor, most of which don't exceed the color gamut of sRGB – and what do most people complain about when they see their digital prints? "It doesn't match my monitor" not "gee, I'm not hitting some colors I know this printer is capable of". They will complain if the blond hair looks a little green, not if the yellow flowers aren't quite as yellow as they could be. I've actually had people complain if the color is more saturated than they expected! In fact any deviation from what they saw on their monitor can be the source of complaint but most of the time people are not that picky if its at least close to the monitor in the impression of the color.

I think we can agree to disagree about what the best workspace is for any given context and stop worrying about the "best" default for anything!

regards,

Lee Varis

President, LADIG

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Re: ProPhoto as default

Posted by: "Ric Cohn"

Sat Nov 25, 2006 10:24 am (PST)

Lee,

Once again you've done a great job of explaining your view in a clear and simple way. Fantastic! Like you, the majority of my color correction is of subtle tonal differences for skin, subtle colors and near neutrals.

I reproduced your test and added in a number of other color spaces. Interestingly, of the color spaces I looked at, only ProPhotoRGB had anywhere near the color change shown with only a 5 level tweak. In particular I was interested in looking at the DonRGB color space that John Castronova mentioned he uses. After applying my "5 level Red curve", his space had only a little more saturation than sRGB or AdobeRGB which I *think* confirms my suspicion that these "Mid-Wide Gamut RGB's" that encompass virtually the entire traditional film gamut (with the possible exception of Velvia) are not nearly as wide as ProPhotoRGB and much less likely to show the kinds of problems that ProPhotoRGB might show.

To lay any doubts to rest, I repeated the test with only a *1* level change to the Red channel. The added redness is clearly visible in ProPhotoRGB, the change is difficult or impossible to see with sRGB, AdobeRGB or DonRGB. I didn't bother to look at any other working space choices. Clearly this one level change represents the smallest change possible in ProPhotoRGB (using Levels anyway) and it's not as subtle as can be achieved with any other "reasonable" working space.

Now my question is, does this mean there's *no* downside to my adopting a space like DonRGB or BetaRGB as my default workspace (as long as I'm careful about sharing these files with strangers, of course)? Using these wider spaces makes sense as they easily cover the gamut of any output device I'm aware of. If I'm really concerned about keeping colors outside of one of these color spaces for some future eventuality I can always fall back on ProPhotoRGB. Thoughts? Dan?

I think this test is a palpable blow to the ProPhotoRGB as a default working space group. Andrew, how do you answer?

Ric Cohn

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Re: ProPhoto as default

Posted by: “Andrew Rodney”

Sat Nov 25, 2006 10:32 am (PST)

And how about doing this (similar) move in LAB? Target the A channel in a 50% gray file in

LAB and move it from input zero to output a mere 2 or 3 and what effect do you see?

Using the same value (increase of 5 units) is way over the top in LAB compared to ProPhoto

RGB.

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Re: ProPhoto as default

Posted by: "MARK SEGAL"

Sat Nov 25, 2006 10:32 am (PST)

Lee,

I looked at your web-link. Interesting. BUT I edit in ProPhoto all the time and it is only by exception that my edits overshoot their mark. One does need to edit in small increments to assure this, but it is usually very controllable - my experience.

Mark Segal

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Re: ProPhoto as default

Posted by: "Ric Cohn"

Sat Nov 25, 2006 12:25 pm (PST)

On Nov 25, 2006, at 12:26 PM, Andrew Rodney wrote:

Using the same value (increase of 5 units) is way over the top in

LAB compared to ProPhoto RGB.

1. I just repeated the test using Lab and the a channel. I see less change than for ProPhotoRGB.

2. This is the specific reason that in his Lab book Dan keeps stressing that Lab is excellent for making large changes and doing things that are difficult in other color spaces, but that it should never be your only color space and that for maximum quality final adjustments need to be made in the final color space. I think this is very clear and I would submit that the same appears to hold for ProPhotoRGB.

I've adjusted many snapshots in Lab and printed them directly. My family and friends all think they look fantastic. That doesn't mean that I couldn't get better results if I made final adjustments in RGB before printing them on my inkjet. It's a balance of time and quality which I'm purposely accepting. I don't think anyone using ProPhotoRGB is accepting this purposely, so the only question is whether they are inadvertently compromising on quality on at least some of their images?

In the end, the only way to *really* know if people would prefer images prepared using a color space smaller than ProPhoto would be to have a large number of experts edit the same images in both ProPhoto and another RGB color space and have people judge them. Perhaps a set of images could be chosen and a list of adjustment types to be applied to each image listed and let each expert set their own amounts for each adjustment (since the amounts would need to be smaller for ProPhotoRGB if the final results were to be similar). I'd say doing a test like this would be very difficult and too subject to mistakes or biases to ever be conclusive. For now it seems to make sense (to me) to use tests like Lee's to try and show what the downsides are.

Ric Cohn

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Re: ProPhoto as default

Posted by: "john castronovo"

Sat Nov 25, 2006 12:38 pm (PST)

And if additional control is required, one can do the edit on a layer and adjust the opacity. I think this solves the problem nicely, or is there a downside I haven't seen yet?

___________________________________________________________________________

Re: Iris printer (was Request for Retraction)

Posted by: "Greg Welch"

Sat Nov 25, 2006 9:03 am (PST)

Thank you Dan for answering my email!

I guess for the time being I'm a lone voice in the....... thread.

Yes I do have control over the ink values and it is in this way that I do many of my important corrections.

In light of your comment, is this type of control available with rips that control the epson type class of printer? If it is and ultimate color gamut is desired wouldn't working with the rip give the most control here too? I would guess that printers using 6, 8 or 12 inks to achieve a great print could possibly print even better work if the printmaker was making ink decisions and not having to rely on a canned formular. This would of course require good eyes, knowledge and desire towards excellence.

Thank you again Dan for your work in advancing practical color corrections. I've been reading your articles for years and years and am honored to be a small part of your list!

Greg Welch

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Iris printer (was Request for Retraction)

Posted by: “Andrew Rodney”

Sat Nov 25, 2006 10:24 am (PST)

On 11/25/06 7:24 AM, "Greg Welch" wrote:

In light of your comment, is this type of control available with rips that

control the epson type class of printer?

Absolutely. Crude in the Epson driver and quite robust in 3rd party products such as those from ColorBurst.

Andrew Rodney

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Re: Iris printer (was Request for Retraction)

Posted by: "Terry Wyse"

Sat Nov 25, 2006 12:22 pm (PST)

On Nov 25, 2006, at 9:24 AM, Greg Welch wrote:

Yes I do have control over the ink values and it is in this way

that I do many of my important corrections.

In light of your comment, is this type of control available with

rips that control the epson type class of printer?

Absolutely! RIPs such as ColorBurst, GMG and several others give you complete ink control. The Epson driver is lame in comparison (no real ink control other than a "media" selection and no real calibration control). Besides ink control and ICC color management, perhaps the best feature of most RIPs is the ability to re-calibrate the RIP/ printer and avoid frequent re-profiling to compensate for printer drift. (By the way, GMG can actually drive an Iris directly).

If it is and ultimate color gamut is desired wouldn't working with

the rip give the most control here too?

The idea behind most RIPs is that, for a given ink/media combo, you set up ink limits, light/dark transfer curves, linearization curves, etc. (options are RIP-dependent) and then you build an ICC profile on top of all that that characterizes that particular calibration setup. You DON'T use the RIP as a "color correction" tool if that's what you're implying. The only wrinkle on this is if you choose to let the RIP handle the color management chores (profile conversions) or if you prefer to perform profile conversions in Photoshop and let the RIP deal with calibration/ink control only. Either way is valid and offers its own strengths and weaknesses.

Regards,

Terry Wyse

_____________________________

WyseConsul

Color Management Consulting

G7 Certified Expert

704.843.0858

http://www.wyseconsul.com

http://www.colormanagementgroup.com

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: Dan Margulis

Sat Nov 25, 2006 10:31 am (PST)

Ric writes,

What I don't understand is the desire to sell working in Ultra Wide

Gamuts to the "masses". With the majority of image creation going to

digital, the de facto encouragement to move from ACR to ProPhoto (8

bit or 16 bit) seems odd or maybe naive. It will take some very

strong proof before I would agree that it shouldn't be considered an

experts only decision.

While it is certainly true that nonexperts take their lives in their hands by editing in ultra-wide RGBs, it's just as bad for those who *are* experts. Serious color correction (i.e. more than minor adjustments) is not feasible in something this clumsy.

RGB and CMYK curvewriting depends on finding target values and adjusting to match them. An exact match is rarely possible. You settle for something near. That's what deadly in an ultra-wide RGB: you may only be able to miss the target by 3 or 4 levels before somebody notices, whereas you can miss by 8 or 10 in a rational RGB. There's no precision in curves or similar commands. Filters don't work as accurately, the effect of noise is greatly magnified and it's more easily produced.

More ironic: it was not very long ago that we were treated to a demonstration how a sufficiently severe move in ProPhoto could provoke a visible difference between an 8-bit and a 16-bit file, an effect that doesn't exist in rational RGBs. Where that happens, it's more likely that the viewer will prefer the 8-bit version but certainly the opposite can also be true. What are we to do, prepare two versions of the file, one in 8-bit and one in 16-bit, and merge them together preserving the areas where each is better?

Dan Margulis

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Re: The Color of Nature: ProPhoto vs. sRGB

Posted by: "Ric Cohn"

Sat Nov 25, 2006 12:35 pm (PST)

Careful what you suggest. There's probably someone out there who will take you seriously and build a workflow around this. <g>

Ric Cohn

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Re: Request for Retraction (was The Color of Nature)

Posted by: "David Marley"

Sat Nov 25, 2006 12:27 pm (PST)

Richard Wagner wrote:

In Canyon Conundrum, Dan uses sRGB throughout

and there is no discussion in that book of using a wider color space...

In the Canyon Conundrum book, Dan explains very thoroughly that sRGB is used as a matter of convenience to keep color specifications as simple as possible.

What "deep magentas and cyans" can be printed on

what "certain printers" that "don't exist in photographs?"

You're kidding, right? How about the over-saturated photo you recently posted?

I do want to thank you for your remarks and info regarding Bill Atkinson's book and the extended-gamut 4-color inkset from Toyo. "Within The Stone" is the most vibrant process-color printing I've ever seen. This has the potential to revolutionize lithographic reproduction. It is refreshing to read information that is pertinent to the majority of Dan's readers.

Although many of the posts on this forum are from professional photographers, I'm certain that most of Dan's audience is composed of graphic designers and prepress craftspeople who make their income in the CMYK and sRGB worlds.

You commented that Dan can be hard to follow. That's the price we pay

to learn how to correct images using all three major color models. The notion of restricting professional work to RGB is an idea that persists in some photography circles -- even Adobe itself. For example, here's a recent quote from one of the Photoshop engineers:

CIE LAB was designed as a model of human visual response, not for a

particular user's editing pleasure.

Now, it seems that only ProPhoto RGB will suffice. I hope the pro-photog crowd can keep us CMYK practitioners in mind as we struggle to maintain detail in the strong reds of fine art reproductions, or to optimize the mediocre blues Photoshop substitutes for the OofG violets in architectural photography. For this work, wide-gamut RGB editing would be suicide.

David Marley

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Re: ProPhoto as default

Posted by: "Ric Cohn"

Sun Nov 26, 2006 7:31 am (PST)

On Nov 25, 2006, at 3:52 PM, Andrew Rodney wrote:

Really? I don’t. Now a 50% Gray fill in LAB isn’t the same as a 50%

fill in ProPhoto RGB

So our methods (or eyes) lead to different results? OK. I'm not sure how Lab reacts changes what I'll call the "Ultra Wide Gamut" vs. the "Wide Gamut" color space issue. I think using sRGB is obscuring Lee's point. AdobeRGB *and* every other color space I've looked at (BetaRGB, DonRGB, L*StarRGB, ColorMatchRGB) are all very close in color to each other and much closer in change to sRGB than to ProPhotoRGB.

Since the a channel is from magenta to green there's no way that a Red adjustment would be identical anyway. Now if I changed both the a and the b to make red I'd expect a bigger change, but then now I'm changing two channels instead of just one. Again, I think this is a side issue to what we're talking about here.

BTW, the way I did my test was slightly different. It might lead to slightly different results, but I can't believe it would change the overall RGB results: I created a document in *Lab* and filled it with 50% gray. I then made a selection and saved it. From this state I converted to my various RGB profiles (going back to the original Lab state so each conversion will be from an identical file), applied my Levels Adjustment (loaded from a saved adjustment to make sure I didn't make a mistake here), deselected the selected and saved each RGB conversion as history states. This allowed me to see the changes between each by clicking on it's history state.

Ric Cohn

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Re: ProPhoto as default

Posted by: Richard Wagner

Sun Nov 26, 2006 7:36 am (PST)

Lee,

I agree with much of what you say in the first half of your post - except, of course, your #2, especially if you work in 16-bit. It is possible to make as subtle an adjustment as you want in ProPhoto...

But to get to the more interesting part:

On Nov 25, 2006, at 8:39 AM, Lee Varis wrote:

I am currently directing digital services for a high-end commercial

photo lab in Los Angeles. This lab (the Icon, inconla.com) does RAW

file processing, large format prints of all kinds, web galleries and

retouching for entertainment industry clients as well as fashion,

advertising and editorial photographers and international clients.

90% of the imagery that comes into the lab is in Adobe RGB, the

remaining 10% is untagged.

Interesting. All those people, and none enlightened enough to use sRGB, where they can see every pixel color on their monitor. ;-) Don't they realize that lots of colors in AdobeRGB will be OoG on their monitors, and that they can't possibly edit those pixels accurately? Heck, they probably don't even know why their cameras give them an option of AdobeRGB output.

I have yet to see anything that comes into

the lab tagged with ProPhoto!

We quit using our lab a couple of years ago. We were never pleased with their prints from digital files (or film), and we no longer have E6 by the hundreds of rolls to process. We bought an Epson 9600 and never looked back. Perhaps many of your pro photographers who are using ProPhoto have done the same, or they're afraid that if they give your lab ProPhoto, your lab will screw it up, so they convert to AdobeRGB first, since they know your lab can handle that.

How could I recommend any other default

than Adobe RGB for the lab! Clients generally expect the files to be

in Adobe RGB and in EVERY case involving an output they want the

print to MATCH THE MONITOR!

I think AdobeRGB is a great color space for the photo masses using labs and for the lab itself - certainly when compared against sRGB. If people learn to Obey Embedded Profiles and your lab uses good profiles, everything works fine. And yes, they want the print to "match the monitor" even though they're comparing emissive and reflective media and even though some of the gamut of the print may exceed that of the monitor. Actually, what they really want is a print that looks better than what they remember seeing on the monitor - but they probably never ask for that.

Nobody, AFAIK, has ever asked for a color

that they can't see on the monitor.

No, but I'll bet if you took a lot of those images that you print and converted them to sRGB first, customer satisfaction would go down. sRGB lops off a healthy amount of AdobeRGB and most printer gamuts. For that matter, why didn't you make the lab standard sRGB, where everyone could see exactly what's on the monitor, and print just that? Don't let them have that extra gamut in a print (or charge more for it!), since they can't see it anyway. Do you give customers refunds for the pixels they can see on their monitor (in ~sRGB), but that you can't print and have to substitute another color for? You know, the OoG colors that occur when you convert to printer space, even from sRGB? Damn, I want my money back! That color was on my monitor and your lab didn't print it!

So, in my particular context, it makes no sense to "default" to

anything else but Adobe RGB!

Well, not by your "see a pixel, print a pixel" logic, but I think it was a reasonable choice for the lab. But, I hope you obey embedded profiles, or it's no wonder that you have no ProPhoto customers. The same would happen if your standard was sRGB and you ignored embedded AdobeRGB profiles. For a "default," why not just obey embedded profiles, regardless of what they are? In fact, if someone then walked in with images in ProPhoto and your lab always obeyed embedded profiles, your lab could probably handle that, too, without breaking a sweat. As far as the "mystery meat" from the 10% of your customers, why not have your desk jockeys help educate them? Who knows what they see on their (probably uncalibrated) monitors at home - how could you possibly match it?

I suspect that most customers of our lab would be well served with sRGB because

most don't use high-end monitors to view their images but Adobe RGB

has become universally accepted among almost every customer as the

"standard" so this is our default. I don't see this changing any time

soon.

And that's where we disagree. Your customers are happy with AdobeRGB **even though they can't see all the colors on their monitors,** because many of those "extra" colors will print. If you edit the colors that are in-gamut, the OoG will very likely fall in place. Seldom does anyone do "pixel editing." We edit with curves, levels, layers, and things that operate on lots of pixels at once. I don't think I've ever looked at a print of mine and said, "Whoa, too much color outside of sRGB - better reduce the gamut to what I can see on the screen!" nor have I tried to select and edit only the pixels that are OoG on my monitor. If you fix what you can see - and Dan has reminded us that you don't even have to "see" in color to edit - it is very unlikely that anything OoG will go bad. Your customers are living proof - and they probably don't even realize that those "extra colors" that they can't see will print. As Dan also made perfectly clear recently, he has never advocated using sRGB for "non-web" RGB output - for good reason. "Work primarily aimed at non-Web RGB: If you are certain that your workflow won't let anyone convert (or fail to convert) it improperly later, use Adobe RGB." So if you can get everyone in your lab to obey embedded profiles, AdobeRGB would be preferred over sRGB.

This is all a rather long winded way of saying I use Adobe RGB, your

mileage will vary!

And I think it's a good color space to be used for pre-press, etc., because it encloses the gamut of CMYK profiles, and it covers 90+% of the gamut of most current printers. There's a reason that it has become a widespread standard for color interchange and the RGB color space for Adobe's North American Prepress Defaults. Right now, it works well for most of what is needed. That doesn't mean that its life span is unlimited, or that it won't be replaced by something larger, like ProPhoto, especially for those who are trying to squeeze all the information possible out of images, and as the gamut of output devices increases. I think your color lab example makes it very clear that even relatively inexperienced people can edit images in a color space that is larger than the gamut of their monitor with pretty good success. After all, your lab seems to have very satisfied clientele, right, and at least 90% of them are editing in AdobeRGB, right?

--Rich Wagner

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Re: ProPhoto as default

Posted by: “Andrew Rodney”

Sun Nov 26, 2006 7:38 am (PST)

On 11/25/06 2:17 PM, "Ric Cohn" wrote:

I'm not sure how Lab reacts changes what I'll call the "Ultra Wide Gamut" vs.

the "Wide Gamut" color space issue. I think using sRGB is obscuring Lee's

point. AdobeRGB *and* every other color space I've looked at (BetaRGB, DonRGB,

L*StarRGB, ColorMatchRGB) are all very close in color to each other and much

closer in change to sRGB than to ProPhotoRGB.

Since the a channel is from magenta to green there's no way that a Red

adjustment would be identical anyway.

Identical, no I agree and that©ˆs not possible. But they are close. The resulting Lab values from the ProPhoto file are within a unit of the Lab edit according the info palette. Visually, I have to use nearly the same number of steps to get the two color spaces to produce roughly the same appearance (and numbers) but not anywhere the same using sRGB. IOW, I need 10 steps for sRGB, 4-5 for both ProPhoto and LAB so I©ˆm suggesting the later two are pretty close to having the same coarseness with respect to numerically altering a file to produce roughly the same color appearance. Considering the size of both spaces, I©ˆd expect that. Now ProPhoto does have a 1.8 TRC which isn©ˆt ideal (2.2 would be more perceptually uniform).

From this state I converted to my various RGB profiles (going back to the

original Lab state so each conversion will be from an identical file),

In my test the files undergo no conversions. I just build them using a gray they both represent. I©ˆm not sure if that makes a difference (I'll have to try your method). I figure, the less conversions going on, the less to muck things up. By setting the Info palette for LAB and RGB, I can move from color model to color model and see if the two correlate numerically. With Gray, before the edit they do. After, the values are within 1.

Andrew Rodney

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ProPhoto as default

Posted by: “Andrew Rodney”

Sun Nov 26, 2006 7:39 am (PST)

On 11/25/06 11:48 AM, "john castronovo" wrote:

And if additional control is required, one can do the edit on a layer

and adjust the opacity. I think this solves the problem nicely, or is

there a downside I haven't seen yet?

Or the Fade command which is very smooth way to tone down the effect along with the use of blend modes.

Andrew Rodney

___________________________________________________________________________

Re: ProPhoto as default

Posted by: “Andrew Rodney”

Sun Nov 26, 2006 7:47 am (PST)

On 11/25/06 12:08 PM, "Ric Cohn" wrote:

1. I just repeated the test using Lab and the a channel. I see less

change than for ProPhotoRGB.

Really? I don©ˆt. Now a 50% Gray fill in LAB isn©ˆt the same as a 50% fill in ProPhoto RGB. So what I did was use the LAB value (L*61) for middle gray which corresponds to 50% gray in ProPhoto RGB (128/128/128) and the two appear the same shade. I have to pump the Red channel up to 132 from 128 to get the same (pretty close) shade or color shift as doing a plus 4 a* move. So they are nearly the same Œcoarseness©ˆ to get a resulting 61/4/1 LAB value in both files. Can©ˆt exactly match the two of course but, it does appear to me, using Lee©ˆs test that there isn©ˆt a big difference in the two. Two get 61/4/1 in sRGB, you have to crank the red up to level 138 (+10) which illustrates Lee©ˆs very valid point about that smaller space having the ability to take a larger correction to achieve an appearance that©ˆs going to take a much smaller correction in a wide space. But Lab isn©ˆt immune by a long shot (my initial point) nor would most people, short of those who have read Dan©ˆs book tell you Lab is an Œeasier©ˆ space to work in.

Andrew Rodney

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Re: ProPhoto as default

Posted by: "john castronovo"

Sun Nov 26, 2006 2:55 pm (PST)

As a custom lab owner for 30 years, I'm grateful that we're finally getting to the point where most people do embed profiles no matter what they are so that we CAN convert from them to our output profiles. The major exceptions are still the printers and agencies who somehow mysteriously work in a vacuum and never embed profiles. I get the clear impression that they think we're incompetent if I ask for a profile, or maybe my question could reveal their lack of knowledge in the area, so I've learned not to ask them. For them we have to use our best judgment. Ironically, their work is the most demanding but they're used to the method of charging customers for proofs and corrections. Who am I to rock the boat?

There are also a great and increasing number of people who come to the lab with profiled images who want their images "improved". For them, it doesn't matter if we match their monitors (or even their files) or not. I have no problem with that, but it illustrates the problem that the lab needs to know up front IF the embedded profile is to be honored. This is now the most difficult part of the workflow. Even Dan's blind test of photo labs earlier this year was faulted because it came without instructions, so it was no surprise that results varied. Some labs opted to honor, some opted to improve and the rest just ran them and let the machine de jour do whatever it wanted to do. All of them are correct on different levels.

John Castronovo

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Re: ProPhoto as default

Posted by: "Ric Cohn"

Sun Nov 26, 2006 2:56 pm (PST)

On Nov 26, 2006, at 12:04 AM, Richard Wagner wrote:

Interesting. All those people, and none enlightened enough to use

sRGB, where they can see every pixel color on their monitor. ;-)

I'll ignore the sarcasm (which even w/ smiley face I thought was unnecessary). I find this whole "sRGB matches your monitor" thing ridiculous. As I understand it, the sRGB space was designed to cover the "average" pc monitor of circa 1985. That is, cheap monitors used by non-imaging professionals. I always thought that the better monitors even of that time could exceed the "average" monitor. Assigning ridiculous, unsupportable arguments to an opponent is just poor form.

Fact: Using a color space that is larger than our monitors has certain advantages and disadvantages. One of the disadvantages is that it makes it harder to know what our final output will look like. Note that I said *harder* not *impossible" or even *difficult*. AFAIK no one on this list is arguing that harder never leads to better results.

Fact: The larger the color space the easier it is to call for numbers that are both not visible on our monitors *and* outside our output devices range *and* will reduce quality over a file that does not call for numbers outside the output devices range.

Fact: The wider the gamut of a space the larger will be the same corrections using Photoshop's available tools. It has already been pointed out that this loss of subtlety can be compensated for. I don't think that anyone can argue that this makes an Ultra-Wide gamut space easier to work in.

Question: With so many spaces out there that are designed to be large enough to encompass all current (and probably future) output devices which are much smaller than ProPhotoRGB and don't appear to show anywhere near the same problems of ProPhotoRGB why are people pushing it so hard?

I suspect that some people, who make their living telling others what to do, got seduced by the idea of this space and endorsed it so enthusiastically, that it is now too politically difficult for them to go back and redefine their position. Probably, like with the 16 bit debate, people on both sides will restate what "they have always" said and we'll come to some true understanding. I hope this doesn't drag on for years. I, for one, would like more facts and examples and less rhetoric.

Ric Cohn

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Re: ProPhoto as default

Posted by: Dan Margulis

Sun Nov 26, 2006 2:59 pm (PST)

Ric Cohn writes,

Now my question is, does this mean there's *no* downside to my

adopting a space like DonRGB or BetaRGB as my default workspace (as

long as I'm careful about sharing these files with strangers, of

course)? Using these wider spaces makes sense as they easily cover

the gamut of any output device I'm aware of. If I'm really concerned

about keeping colors outside of one of these color spaces for some

future eventuality I can always fall back on ProPhotoRGB. Thoughts? Dan?

Adobe RGB came about by a proofreading error at Adobe. Its structure makes no sense--wildly extravagant greens, unreasonably muted blues and red. Any RGB of approximately the same gamut designed by anybody with even the slightest awareness of color issues is going to be theoretically superior.

But you have to ask yourself what good, and what harm, are you doing by bringing up this question? How often are you going to encounter an image where it might conceivably be helpful to be working in a space of similar gamut to, but more sensibly designed than, Adobe RGB? How many images are you going to find that, say, have a purple that Adobe RGB can't handle, a more sensibly designed RGB can, AND can still be printed?

Yes, it's possible, and yes, there may be some cases where the excess green gamut of Adobe RGB can hurt you. In the overall scheme of things, though, the gain is slight.

Now, consider what you're risking by even bringing up the discussion. The RGB working space is one of the few areas in imaging where superior technique has not won out and instead, really stupid things have happened.

I don't wish to reopen old wounds, but think of what the geniuses who threw Adobe RGB at the world, rather than some more sensible space targeted at professionals, accomplished. A few of us are able to get marginally better results on certain images than would have been possible in the old days of Apple RGB. Many more, IMHO, have ruined images by driving them to extremes in Adobe RGB, so on the whole I would say quality has suffered.

That is *before* you take into account that the industry was thrown into chaos for two years before we stabilized on a couple of standards; that millions of dollars worth of images (and some careers) were ruined because of misinterpretation of embedded profiles, that now users have to spend a lot of time learning something that has limited impact on quality other than the potential to hurt it, that handing off an RGB file to a stranger has become a form of Russian Roulette, relations between users and service providers have been poisonged, and that lists like this one spend thousands of times more time on the topic than it could possibly justify, to the detriment of discussing things like sharpening and channel blending that can actually create immediate improvements in quality.

And with all that effort, we got two awful RGBs as standards--Adobe RGB and sRGB.

Reason takes second place when the choices are vendor-driven. The printer companies and their touts love that we waste our time talking about these issues, because their profit margins come from ink sales. And the less said of the Photoshop team's record in this area, the better.

You can see what you're up against by this present thread. It is hard to believe that in the 21st century, anyone can seriously suggest something as ridiculous as ProPhoto RGB as a working space. It's hard to believe that in the 21st century, someone can seriously suggest handing out Adobe RGB to strangers and hoping for the best. Yet that's where we stand.

So, yeah, if we were starting from scratch, I'd advocate something better than AdobeRGB. The images that might need something larger are readily identifiable, and for those I'd use LAB or a larger RGB on a case-by-case basis. So I'd vote for something smaller on the whole, but with more vivid reds and blues.

We are not, however, starting from scratch. The very people responsible for the present mess are likely to make it even worse if given a chance. Under these circumstances, I recommend biting the bullet and saying, look, you guys have retarded the progress of the industry enough. We've stabilized on something that works now, so let's stick with it rather than doing something that pleases vendors at the expense of the quality of our images.

Dan Margulis

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Re: ProPhoto as default

Posted by: "Ric Cohn"

Sun Nov 26, 2006 3:03 pm (PST)

On Nov 25, 2006, at 10:39 AM, Lee Varis wrote:

90% of the imagery that comes into the lab is in Adobe RGB, the

remaining 10% is untagged. I have yet to see anything that comes into

the lab tagged with ProPhoto!

Out of curiosity, where do the 10% of untagged profiles come from, and who are they from? It's hard to output an untagged RGB from Photoshop. Are these direct from digital cameras with no work done on them?

Also, I'm not surprised 90% of the files you receive are AdobeRGB. I went to the iconla.com website and 1). The primary clientele appear to be professional photographers and 2). the specs on the site asks for tagged RGB files in one of 3 spaces: Adobe, sRGB or ColorMatch. It implies that any other tagged space is unacceptable to Icon! Did you know this was on the site? Seems rather self limiting, and yes, I would think there might be a small number of knowledgeable people who work in other spaces who either convert their files or pass up Icon when they see this. I know if I had files in a different space to output and I felt there was another equally good vendor choice I'd go elsewhere rather than comply with what I saw as an unnecessarily restrictive and uneducated limitation.

Ric Cohn

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ProPhoto as default

Posted by: “Andrew Rodney”

Mon Nov 27, 2006 4:41 am (PST)

On 11/26/06 12:57 PM, "Ric Cohn" wrote:

As I understand it, the sRGB space was designed to cover

the "average" pc monitor of circa 1985. That is, cheap monitors used

by non-imaging professionals.

True indeed. For fun, I just plotted the gamut of my admittedly just OK iMac LCD to sRGB and my display has a larger color gamut. Along an entire slice of the color space running from the red to the green primary, it©ˆs larger. The yellow is larger as well. By a lot? No but larger. My Sony Artisan gamut is larger still.

On 11/26/06 2:04 PM, "Dan Margulis" wrote:

Adobe RGB came about by a proofreading error at Adobe.

I know how you love to pile grief on Adobe but that©ˆs simply incorrect. In fact, the SMPTE had the incorrect chromaticity values on a web site discussing their new synthetic color space known (and presented in Photoshop 5) as SMPTE-240M. Should Adobe have picked up the phone and asked if the values were correct? Maybe. But the fact remains that despite the name change in Photoshop 5.0.5 to Adobe RGB (1998), since 1998, thousands, perhaps millions of images have been encoded into this space and, other than on this site, I©ˆve yet to hear how this has amounted to so many hosed files. Yes, as you point out, a bonehead user who doesn©ˆt know an embedded profile from a pickle, who doesn©ˆt have a calibrated display or has taken BAD advise by setting his Photoshop settings to ©¯Off©˜ (which isn©ˆt off) might very well hose a file. And how many people have converted to generic CMYK under the impression that there©ˆs only one CMYK color space? I keep asking why you have to dredge up unsubstantiated statistics about all these hosed files by clueless users and how that has anything to do with anyone who©ˆs interested in using sound imaging practice. Thousands of Americans don©ˆt wear seat belts and are killed every year in car accidents. So going back to the horse and buggy therefore makes a lot of sense?

Its structure makes no sense--wildly extravagant greens, unreasonably muted

blues and red. Any RGB of approximately the same gamut designed by anybody

with even the slightest awareness of color issues is going to be theoretically

superior.

We all await Dan RGB.

But you have to ask yourself what good, and what harm, are you doing by

bringing up this question? How often are you going to encounter an image where

it might conceivably be helpful to be working in a space of similar gamut to,

but more sensibly designed than, Adobe RGB?

Based only on my collection of captured images, quite a lot. Perhaps you can share with us the digital camera you©ˆre using or the gamut of the RGB from your scanner and maybe provide some raw files to see if any at all fall outside Adobe RGB (1998). I would submit if you shoot a lot of gray cards, you©ˆll easily find they all fall within sRGB. Not knowing your shooting style, I can only guess how often your images fall sensibly in Adobe RGB (1998).

How many images are you going to find that, say, have a purple that Adobe RGB

can't handle, a more sensibly designed RGB can, AND can still be printed?

Good question. So I rendered a digital capture of a 24 patch Macbeth Color Checker in Adobe RGB and landed into ColorThink. Those purples OK for you? Cause they fall just to the boundaries of Adobe RGB gamut and clip big time in sRGB (as do cyans, greens and yellows).

I don't wish to reopen old wounds, but think of what the geniuses who threw

Adobe RGB at the world, rather than some more sensible space targeted at

professionals, accomplished.

Sensible? We©ˆve heard from a number of photographers here, a body I think is both professional and sensible, that working in Adobe RGB (1998) hasn©ˆt caused any form of cancer on their files. Can I attribute this in some ways to time spent on this list?

A few of us are able to get marginally better results on certain images than

would have been possible in the old days of Apple RGB. Many more, IMHO, have

ruined images by driving them to extremes in Adobe RGB, so on the whole I

would say quality has suffered.

Yes, we©ˆve heard that. Where are these users? What was their skill level at the time? Before or after taking your class? Where are the masses of users who©ˆve destroyed all these images?

And with all that effort, we got two awful RGBs as standards--Adobe RGB and

sRGB.

Awful? Again, we await Dan RGB. Also, there are no perfect RGB working spaces, they all have advantages and disadvantages. As I©ˆve said over and over, we are always putting round holes in square pegs. We can©ˆt see all of SWOP on our displays. We have to capture in RGB. The idiosyncrasies of device dependant capture devices is often a far worse space than the well behaved synthetic spaces where we have control over gray balance and we have a family of gamuts to work with.

Reason takes second place when the choices are vendor-driven.

Oh please stop. So Adobe is making money off a synthetic color space built by the SMPTE?

You can see what you're up against by this present thread. It is hard to

believe that in the 21st century, anyone can seriously suggest something as

ridiculous as ProPhoto RGB as a working space.

Well I guess some of us kids are just ridiculous...

So, yeah, if we were starting from scratch, I'd advocate something better than

AdobeRGB.

Such as?

The images that might need something larger are readily

identifiable, and for those I'd use LAB or a larger RGB on a case-by-case

basis.

What tools do you suggest for making these evaluations?

Andrew Rodney

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Re: ProPhoto as default

Posted by: Richard Wagner

Mon Nov 27, 2006 4:42 am (PST)

John (and Lee),

I don't for an instant envy anyone running a lab in this day and age; it would be a nightmare in my book. I've heard lots of stories - "I want 11x14's from this image, and it looks great on my monitor" (1024x768 JPG), etc., etc. Many pros have bailed from commercial labs and are doing their own work, and any Joe with a camera and a copy of Photoshop Elements thinks he's a pro. And yes, everyone wants their images to look better than the monitor - regardless of who edited the image or what color space it's in or what's been done to it. And yes, "creatives" are still often more creative than knowledgeable. Your points are all valid. Life was easier for labs when photography was film-based.

Three years ago at a NANPA national meeting, the publisher of a well- known outdoor photography magazine told this group of photographers that the first thing they did with digital submissions was to "strip out the profiles and look at the images on our high-quality monitors to tune them up." You could hear the moans and groans throughout the auditorium. So yes, I think many of us are grateful that embedding profiles is becoming the standard, as well as obeying profiles, unless there are instructions to do otherwise. Embedded profiles are part of the solution, but they're not the complete solution, especially in a commercial digital lab. They do usually at least provide a good starting point.

Manage a commercial lab? No thanks! But my hat's off to you guys who do.

--Rich Wagner

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Re: ProPhoto as default

Posted by: "Bob Frost"

Mon Nov 27, 2006 4:42 am (PST)

Ric,

For facts, it is probably worth reading Kodak's papers on why they invented the space, if you haven't done so already.

http://www.scarse.org/docs/kodak/ProPhoto.pdf -- the first para says:-

"A new color space known as Reference Output Medium Metric RGB (ROMM RGB) is defined. This color space is intended to be used for manipulating images that exist in a

rendered image state. This color space was chosen to provide a large enough color gamut

to encompass most common output devices, and is defined in a way that is tightly linked

to the ICC profile connection space (PCS). Examples of manipulations that might be

applied in this color space include scene balance algorithms, manual

color/density/contrast/ tone scale adjustments, red-eye correction, and dust/scratch

removal. The color space is also appropriate for archiving and/or interchanging rendered images. 8-bit, 12-bit and 16-bit versions of this color space are defined."

They went on to say:

"It is therefore desirable to define a new standard large gamut color space that can be used for storing and/or manipulating color images. The color space should have a number

of characteristics:

. It should be tightly coupled with the ICC Profile Connection Space.

. The transform to/from PCS should be relatively simple.

. The transform to/from video RGB should be relatively simple.

. The color gamut should be large enough to encompass most common output devices.

. The Color space should be appropriate for common image manipulations such as tone

scale modifications, sharpening, etc.

. It should be easily extensible to different bit-precisions.

These criteria are all met by the Reference Output Medium Metric RGB (ROMM RGB) color space that will be described in the next section."

"One potential use of the ROMM RGB color space is as a working color space for Adobe Photoshop software."

I leave you to read the rest.

Bob frost

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Re: ProPhoto as default

Posted by: "MARK SEGAL"

Mon Nov 27, 2006 4:43 am (PST)

Ric Cohn wrote:

I suspect that some people, who make their living telling others what

to do, got seduced by the idea of this space and endorsed it so

enthusiastically, that it is now too politically difficult for them

to go back and redefine their position. Probably, like with the 16

bit debate, people on both sides will restate what "they have always"

said and we'll come to some true understanding. I hope this doesn't

drag on for years. I, for one, would like more facts and examples and

less rhetoric.

It'll drag on as long as people have more or less useful things to say about both issues. As for facts and examples, (a) I'm not marketing either photographs or intellectual positions so I have no vested interests, but (b) I guess I've processed about 1500 or so ink-jet prints over the past year in 16-bit mode ProPhoto working space and the vast majority of them are from a technical perspective fully satisfactory. But as time permits I'm working on both issues with an open mind to better see for myself the practical signifigance of the arguments.

Mark Segal

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Re: ProPhoto as default

Posted by: "Bob Frost"

Mon Nov 27, 2006 4:44 am (PST)

Dan,

And with all that effort, we got two awful RGBs as standards--Adobe RGB

and sRGB.

Isn't that why Kodak invented RommRGB, later renamed ProPhotoRGB? ;)

Bob Frost.

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Re: ProPhoto as default

Posted by: "Lee Varis"

Mon Nov 27, 2006 4:45 am (PST)

On Nov 26, 2006, at 11:23 AM, Ric Cohn wrote:

the specs on the site asks

for tagged RGB files in one of 3 spaces: Adobe, sRGB or ColorMatch.

It implies that any other tagged space is unacceptable to Icon!

Yes... (sigh) this is just plan silly! These "specs" were in place before I joined the lab. I'm not sure most of our customers even know that they are there. We are redesigning the web site and one of my responsibilities is to make sure that the information content and the lab policies are up to date. Officially, I'm telling all clients and lab employes that customers should supply files with some kind of profile tag - anything is acceptable – we will convert to the necessary output profile anyway. In the absence of any profile we first assume Adobe RGB unless it looks too dark then we try ColorMatch!

As far as the 10% that supply untagged files these are almost always ad agencies who have been working with digital files for a while. I'm afraid this group is still suffering from the Photoshop 5 fallout. Many old time digital users were burned by the sloppy implementation of color management in PS 5 and they still believe that profiles are pure evil. They will jump through hoops to try and "turn off" color management and make sure that no profiles are embedded in files that go out into the world at large. Ironically, this group is not that big a challenge - its relatively easy to tell whether the file was worked up in Adobe RGB or Colormatch (which appear to be the main choices with most favoring Colormatch) and we can usually convert appropriately. The biggest problems come from inappropriate profiles, i.e. clients "assigning" the wrong profile because they don't know what they are doing.

I think I can safely say that 90% of our customers have no workable knowledge of color management principles and yet most do professional work with digital image files. It is the lab's challenge to protect these clients from themselves – give them better work than they deserve and in turn help their clients so that everyone ends up looking good. It can be quite difficult to do this and protect against someone who will be very picky about matching their monitor, matching their own epson print or matching a print made several years ago by some other lab.

I would think there might be a small number of knowledgeable people

who work in other spaces who either convert their files or pass up

Icon when they see this.

Anyone savvy enough to be successfully working in ProPhoto will most likely have their own 9600 to do fine art level prints. If they need to make 48 x 60 Lightjet prints they will still come to our lab because frankly there aren't many options in Los Angeles. There is no way any lab can be competitive enough in price to grab work from people who are smart enough to figure out how to use a large format inkjet printer and have enough volume of work to support the expense. That still leaves a lot of high-end photographers who: 1. don't have the time to do their own prints or 2. don't need to do prints often enough to justify the expense of the equipment. We also do a lot of retouching, RAW file processing, web galleries and other high volume file management chores, in some cases, for those ex-customers who are making their own Epson prints!

regards,

Lee Varis

President, LADIG

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Re: ProPhoto as default

Posted by: "Rich Wagner"

Mon Nov 27, 2006 4:46 am (PST)

On Sun, November 26, 2006 12:57 pm, Ric Cohn wrote:

I'll ignore the sarcasm (which even w/ smiley face I thought was

unnecessary). I find this whole "sRGB matches your monitor" thing

ridiculous. As I understand it, the sRGB space was designed to cover the

"average" pc monitor of circa 1985. That is, cheap monitors used

by non-imaging professionals. I always thought that the better monitors

even of that time could exceed the "average" monitor. Assigning

ridiculous, unsupportable arguments to an opponent is just poor form.

Ric,

All sarcasm aside (and attempts at humor from this dead-serious debate), have you compared the gamut of your monitor to sRGB/AdobeRGB? Or the typical PC/Mac monitor that Lee's customers are likely using? (Are most of his customers "imaging professionals" with high-end monitors? Do you know many graphic artists with Eizo CG 221's? Photographers? Households?) The average monitor is probably not all that much better than sRGB, and most come no-where close to AdobeRGB. Not my Artisans, not my Eizo CG210... and I'd love to see the profile of whatever you're using. It's very easy to compare gamut plots - and it's very objective.

We can get back to the facts real quick. Sorry to have offended you.

--Rich Wagner

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Dan's audience (was Request for Retraction)

Posted by: Dan Margulis

Sun Nov 26, 2006 10:08 am (PST)

David Marley writes,

Although many of the posts on this forum are from

professional photographers, I'm certain that most of Dan's

audience is composed of graphic designers and prepress craftspeople

who make their income in the CMYK and sRGB worlds.

No, that's less than half of the people who attend my classes now, probably more like a third. Professional Photoshop appeals to that market but is heavily read by photographers; the audience for Photoshop LAB Color appears to be primarily RGB-oriented.

I just got done teaching the advanced courses for this year, 14 people total, and the group consisted of seven current or former photographers, five 40-hour a week retouchers, and two people who don't fit into either category--they have to do a substantial amount of image manipulation in their work, but it isn't their full-time concern.

Four of the group reported that 90% or more of their files end up in CMYK, four 90% or more RGB, and six a combination.

Six often have to work with very poor originals, four because the work they do requires them to process things shot by amateurs, and two because they are photographers who are forced to shoot under very challenging conditions.

The RGB working spaces: 10 Adobe RGB, 2 sRGB (both photographers), 2 homegrown spaces that are somewhat narrower than Adobe RGB but wider than ColorMatch RGB.

The biggest growth group over the last years: people who have made their money in other fields but are so serious about their photography and printing that they aspire to have quality as good as any professional could produce. (Two of those in the group named above).

The biggest loss by far is traditional professional photographers--at least, those who have not adapted their business practices to survive in this world. Virtually all of the photographers I now see are deriving substantial portions of their income from image-related services beyond pure photography.

The biggest trends in practice are reflected above:

1) It is far more likely to have a mixed workflow--both RGB and CMYK output--that at any time in the past. Three years ago the typical class was about 60-40 CMYK to RGB. Now, mixed use is bigger than either.

2) Everybody has to work on inadequate originals from time to time, but a much higher number of us now have to work on inadequate originals a *lot* of the time, due to the migration of professional-quality digicams into the hands of persons who don't know how to use them properly.

Dan Margulis

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Re: ProPhoto as default

Posted by: "Ric Cohn"

Mon Nov 27, 2006 8:52 am (PST)

On Nov 27, 2006, at 5:32 AM, Bob Frost wrote:

For facts, it is probably worth reading Kodak's papers on why they invented

the space, if you haven't done so already.

Yes, I've read this. The structure of ProPhotoRGB isn't in question. I've said before that I consider ProPhotoRGB a very well designed space. The only conclusion I question is whether it is optimum for fine image editing. I'm not categorically denying this, but I am questioning it and I certainly wouldn't adopt it as my working space without a lot more information. What's missing in this paper is any validation by photographers or comparison with results from other color spaces. I have great respect for the technical prowess of the Kodak scientists and engineers. However, they have unleashed many "boo boos" over the years. In my experience, Kodak concentrates on the masses-- whether this is the amateur market or the Pro wedding and portrait market which is larger and uses much more of what they sell than Art, Nature or Advertising photographers for example. I've rarely found an area where Kodak's default recommendations couldn't be improved on for higher quality or personal artistic expression. Bottom line: I'm looking for more than just Big Yellow telling me what they think is best for me.

Ric Cohn

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Re: ProPhoto as default

Posted by: "MARK SEGAL"

Mon Nov 27, 2006 10:56 am (PST)

Ric Cohn wrote:

I certainly wouldn't adopt it as my working space without a lot more information.

The best information you will ever get is to try it yourself under a range of conditions and see whether it floats your boat.

Mark Segal

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Re: ProPhoto as default

Posted by: "Hoffner, Randall N"

Mon Nov 27, 2006 7:29 pm (PST)

Looking at television color spaces as compared to the sRGB and Adobe RGB spaces is interesting, and a little confusing.

I don't know what erroneous CIE chromaticity coordinates SMPTE posted for 240M back then, but the coordinates in the current standard are the same as those of SMPTE 170M. 240M is the standard for the (now obsolete) HDTV scanning format based on the Japanese Hi-Vision system: 1125 total lines, 1035 active lines, which was known as 1035i. 170M is the NTSC standard.

The currently used HDTV scanning formats, 1080 (both 1080p and 1080i) and 720p, use the ITU 709 color space, the CIE chromaticity coordinates of which are pretty close to those of sRGB. Both of these spaces were of course developed in the CRT era, with available CRT phosphors in mind.

Adobe RGB seems to be an amalgam of sorts. Its red coordinates are those of 709; its blue coordinates are close to those of sRGB and the original 1953 NTSC; and its green coordinates are very close to those of 1953 NTSC, giving it a considerably wider green gamut than either 709 or the current NTSC. Although it is still cited in SMPTE 170M, 1953 NTSC colorimetry was de facto abandoned fairly quickly because the appropriate green phosphor did not make bright enough pictures.

Randy Hoffner

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Re: ProPhoto as default

Posted by: "Howard Smith"

Mon Nov 27, 2006 7:34 pm (PST)

Lee,

Those were some excellent points, several of which suggested new ways of doing things. Someone may have responded with a message similar to the following (I'm way behind on my e-mail). If not, some folks may find this observation to be useful.

Using a ProPhoto RGB image for blending into an Adobe RGB image, not just into a duplicate ProPhoto layer is a great way to enhance colors. Surprisingly, to me at least, you can blend two RGB images without regard to their profiles. The same thing can be done with CMYK images. Convert a Pro-Photo version to CMYK, then blend it into a CMYK version made from an Adobe RGB file. At least according to the information bar in Photoshop the bottom image determines the final profile. Use a Selective Color adjustment layer to adjust any colors that need it, especially blues. You can come out with a CMYK file that looks remarkably like the original Adobe RGB image because the ProPhoto layer helps retain colors that otherwise would be muted in the conversion. Maybe this is not practical in the real world, but I wouldn't know as I no longer do any work intended for offset printing. Just a thought for anyone interested in trying something different.

As for the observations about the different ways of looking at images (match the original subject vs. using artistic interpretation), aren't we all trying to produce images that please our intended market? Does anyone besides the photographer really care which approach is used so long as the final image meets that need? Or for images we do for ourselves, do we really care more about correct procedure than about getting an image that pleases us? In earlier editions of Professional Photoshop, Dan puts a lot of emphasis on analyzing images to try to determine how the original scene or subject appeared to the observer. It's a great exercise, and certainly of considerable educational value, but not necessarily something about which we should hyperventilate when it comes to doing real world images. Who really cares if the brown fedora had a touch of magenta in it or if it was more of a greenish brown? It can be important to know or to deduce the true color in order to assure ourselves that we are getting maximum color fidelity in our corrected image, but suppose the client likes his images to have a slight green tint. We can't very well insist that our way is better because it reproduces colors true to the original scene and the original scene did not have any green tint in it.

My own biased approach to Photoshop is to take bits and pieces from everyone's "best way" and mould them into my own way of doing things. The results are not always politcally correct, but it gets the job done and keeps me happy.

If it takes heated arguments to keep the ideas flowing in, go for it!

Howard Smith

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Re: ProPhoto as default

Posted by: "Murray DeJager"

Mon Nov 27, 2006 7:37 pm (PST)

Hi Everyone,

Wow! When I left this list a few days ago I figured everything that could be said about gamut spaces had already been said. But I see this thread is still going.

So, who's winning the argument? Is Dan now using Prophoto exclusively? Or are Andrew and Richard now working within the less colorful world of sRGB?

Actually I quickly read through the posts and, as I suspected, nobody's position has changed. Surprise... surprise!

After reading over a few days worth of posts there's actually only one thought I would like to share with the group.

The thought I have regards discussion of why 80-90% of photographers use AdobeRGB. I would guess that most of those photographers are like me, in that they haven't got a clue of their own as to what space is best and are merely mimicking what the majority of others are doing.

Why is it such a difficult subject for the average photographer? Easy... just read the past threads on which color space is best. If the experts in the field can't agree, and I don't want to appear to my fellow photographers as a fool then maybe sticking to some 'middle-of-the-road' space like AdobeRGB is safest!

Now, if the first non-beta version of ALR and the next versions of ACR and Photoshop eliminate all RGB colorspaces except Prophoto then I guess I'll have to adjust my workflow.

--- In colortheory@yahoogroups.com, MARK SEGAL wrote:

The best information you will ever get is to try it yourself under a

range of conditions and see whether it floats your boat.

Mark, you hit the nail on the head! That's exactly what I've been doing

lately.

Murray DeJager

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Re: ProPhoto as default

Posted by: "John Denniston"

Tue Nov 28, 2006 3:23 am (PST)

At 04:50 PM 11/26/2006 -0700, Andrew wrote:

And how many people have converted to generic CMYK under the

Hi Andrew,

I know two.

The first was a photographer friend I was helping solve a problem he had with his print shop and the second was the person he was dealing with at the print shop. I explained the facts of life to my friend and later tried to do the same with the owner of the print shop but gave up when he told me he had CMYK monitors.

Regards,

John Denniston

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Re: ProPhoto as default

Posted by: "john castronovo"

Tue Nov 28, 2006 7:16 am (PST)

That's almost as good as the art director who insisted that I knew absolutely nothing because his printer told him that CMYK had more color gamut than RGB because it had more plates. Needless to say, I didn't get his business.

john castronovo

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Re: ProPhoto as default

Posted by: "Bob Frost"

Tue Nov 28, 2006 7:16 am (PST)

Ric,

Ok, I wasn't sure whether you had seen that paper - it seemed to be serious rather than marketing stuff.

The only conclusion I question is whether it is optimum for

fine image editing.

Well, Dan has just said that Adobe98 isn't optimum for editing - it was a mistake, and sRGB certainly wasn't devised as a space for fine image editing, but as a space that would allow the non-use of profiles for the masses.

So we have left a string of spaces that WERE devised for fine image editing such as EktaSpace, BestRGB, DonRGB, BetaRGB, and ProPhotoRGB.

How do we decide which are suitable and which aren't? What are the criteria? Let's have some standard tests that we can all try.

Bob Frost.

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Re: ProPhoto as default

Posted by: Ric Cohn

Tue Nov 28, 2006 9:09 am (PST)

On Nov 27, 2006, at 1:59 PM, Bob Frost wrote:

How do we decide which are suitable and which aren't? What are the criteria?

Let's have some standard tests that we can all try.

Good point. I too would like someone to take a stand for something other than ProPhotoRGB. At this point that is the only space that anyone here is vigorously defending as the "right" choice.

To your list of possibly better working space choices I'd add something like ECIRGB or L*StarRGB which are smaller than AdobeRGB in some areas (especially greens) and larger in others (especially reds).

I know Dan doesn't think it's worth worrying about, but I think there are so many implications in this argument that it's worth trying to come to a consensus. Also, the problem with more important image quality issues like channel blending, sharpening, aesthetics, etc. is that once you learn it there's always more to learn and each image needs to be looked at individually. There is something to be said for reducing the number of things we need to think about.<g>

Ric Cohn

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Re: ProPhoto as default

Posted by: Richard Wagner

Tue Nov 28, 2006 1:57 pm (PST)

Well, of all the color spaces other than sRRGB and AdobeRGB that have been listed here, ROMM RGB (ProPhoto) is the only one that has made it through the vetting of Standards committees to become a new standard. The reasons it has are well-described within the standards themselves. A lot of people put a lot of work (and argument) into the new standards.

ANSI/I3A IT10.7666-2002

Photography - Electronic Still Picture Imaging - Reference Output Medium Metric RGB Color Encoding (ROMM-RGB)

http://webstore.ansi.org/ansidocstore/product.asp?sku= ANSI%2FI3A+IT10%2E7666%2D2002

ISO+22028-1-2004

Photography and graphic technology - Extended colour encodings for digital image storage, manipulation and interchange - Part 1: Architecture and requirements

http://webstore.ansi.org/ansidocstore/product.asp?sku= ISO+22028%2D1%3A2004

The latter, in particular, is a 48-page document that reads like a book chapter (or a small book). I would send it to you, but it is copyrighted and my purchase info is watermarked into the PDF. The advantages of ROMM-RGB are extensively detailed. I think it would be reasonable to quote a small section without violating copyright:

Annex C

Criteria for selection of colour encoding

C.1 General

A set of guiding principles for making the appropriate selection of colour encodings for image storage,

manipulation and interchange in digital photography and graphic technology applications is as follows.

—Retain as much colour information as needed for as long as needed.

—Facilitate the compositing of images from different sources.

—Preserve the option of going out to a multiplicity of output devices.

—Communicate colour appearance, not just colorimetry.

—Facilitate the editing of images so that image quality is maximized.

—Minimize computational and storage overhead.

—Maximize interoperability across vendors, applications and products.

—Ensure compatibility with standards and other common workflows.

All of these topics (and more) are then covered in detail. The standard also notes that:

CIETC8-05 is in the process of developing and documenting quantitative metrics that

can be used for the evaluation and comparison of various colour encodings. The metrics that they are compiling

should be directly applicable for the evaluation of many of the criteria that will be discussed in the following

sections.

So people a lot smarter and more educated about the science of color than any of us on this list have been studying color spaces, and the advantages of each. ProPhoto has come out on top, and it has become a standard. Other well-known color spaces have not. The reasoning behind the decisions are available, but it will cost you $$ if you want the details, because unfortunately the standards are not freely distributed.

--Rich Wagner

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Re: ProPhoto as default

Posted by: "RJay Hansen"

Tue Nov 28, 2006 2:04 pm (PST)

Perhaps searching for the "One True RGB Color Space" is futile. Just as there is no "One True CMYK Space", many factors would play into the RGB space you use. What's appropriate and works well for Rich and Andrew's workflows isn't necessarily what's appropriate for *everyone* else. As capably expounded by Lee Varis' recent posts.

I think what bothers many about this thread is the notion that there is a "right" choice. In all circumstances.

RJay

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Re: ProPhoto as default

Posted by: "Mark Segal"

Tue Nov 28, 2006 3:39 pm (PST)

I think what bothers many about this thread is the notion that there

is a "right" choice. In all circumstances.

I think this is a key point, and something I have written about elsewhere (on Luminous Landscape) in the context of scanning color negatives. But it isn't necessarily just workflow or photographer-related. I think the choice mainly varies depending on what works best for individual images, given any workflow and image processing environment.

Mark Segal

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Blending ProPhoto Channels Into Other Images (was ProPhoto...)

Posted by: Stephen Marsh

Wed Nov 29, 2006 5:44 am (PST)

Howard Smith wrote:

Using a ProPhoto RGB image for blending into an Adobe RGB image, not

just into a duplicate ProPhoto layer is a great way to enhance colors.

Surprisingly, to me at least, you can blend two RGB images without

regard to their profiles.

If I understand you here Howard, there would be two common ways to "blend" two different RGB profile images (or CMYK).

Apply Image and dragging layers or copy/paste.

Apply image predates profiles and is simply "stamping" channel data with various blending options (one can go further using duped layers and layer style blending options instead of stamping to a single background layer image).

Apply image has the added advantage of being able to mix the source and destination colour modes, so you could apply the green channel from a wide gamut RGB profile image into a dupe of the CMYK flat background image and blend in luminosity, blend if, opacity etc. There are many options!

Copy/paste or the move tool to layer two documents would bring up a colour management message in many cases (depending on user colour settings) - where one would choose to not alter/colour manage the pixels to access the original detail in the wider gamut file.

Was this in reference to composite or single source channels?

Regards,

Stephen Marsh.

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Re: ProPhoto as default

Posted by: Andre Dumas

Wed Nov 29, 2006 9:00 am (PST)

Hello Howard,

You said: "Dan puts a lot of emphasis on analyzing images to try to determine how the original scene or subject appeared to the observer." Howard, I felt a lot of pain when I read your statement and shouted: "yes but not always" (referring to a particular image in his new book).

You add: "We can't very well insist that our way is better because it reproduces colors true to the original scene." You (are) may be right but still, I feel that my way would have been better (!)

Howard what you say in your message is so very true, "real world" and close to my reality, but I also feel like you (?) that the discussion about ProPhoto vs. sRGB vs. aRGB is very important.

André Dumas

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Re: ProPhoto as default

Posted by: "Bob Frost"

Wed Nov 29, 2006 9:06 am (PST)

Rich,

The reasoning

behind the decisions are available, but it will cost you $$ if you

want the details, because unfortunately the standards are not freely

distributed.

If they were 20$ or so I'd buy one, but at 124$ I'll rely on your abstracts! Can we have some more snippets at discrete intervals?

Bob Frost.

___________________________________________________________________________

Re: ProPhoto as default

Posted by: "Andrew Rodney"

Wed Nov 29, 2006 12:39 pm (PST)

On 11/29/06 7:26 AM, "colorman042000" wrote:

Keeping asking yourself: Scene referred or output referred? I hear scene

original. So we all agree this is scene referred?

Reproduces color true to the original. Scene referred or output referred? Reproduce implies output referred. It can©ˆt match the original.

Andrew Rodney

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Re: ProPhoto as default

Posted by: Mark Segal

Wed Nov 29, 2006 12:49 pm (PST)

Actually, from what I've been seeing out of my printer, I find the discussion is much less important than others may think - much more time and verbiage than the matter deserves. I'll have more to say about that in a week or so.

Mark Segal

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Re: ProPhoto as default

Posted by: Andre Dumas

Wed Nov 29, 2006 4:37 pm (PST)

Hello Andrew,

You say: "Reproduce implies output referred. It can't match the original. Lets try to be specific about what exactly we're talking about here."

I agree that every word counts and the meaning must be clear, when I read you I immediately saw the full meaning of the word "*re*produce" (we are no longer dealing with the original).

Anyway, what I meant to say regarding Howard's statement and Dan's image is that even though "output referred" "cannot match the original" I feel that in many instances (landscape photography for instance,) *I feel * that it is very important that the output reflects as closely as possible the *spirit* of the scene as I saw it originally and which prompted me to photograph it.

Sixteen years ago on my website http: //www.magma.ca/~dumas/ I spelled out the philosophy that motivated me in photography and if you have a look at it you will see that it has less to do with the technicalities of our subject and more to do with human perception (memory) of the original scene and the desire to share it with others.

I see your point Andrew, now if I could only match what I was 16 years ago that would be great.

André Dumas

___________________________________________________________________________

Re: ProPhoto as default

Posted by: "Lee Clawson"

Wed Nov 29, 2006 8:52 pm (PST)

Ric,

While I've stayed out of this thread (I'm too far behind with studio work to keep up) I do think its worth all the "worrying" and debate..

And this isn't restricted to color and image processing concepts. The folks in audio are having the same discussions. They are as far along as we are in the capture of digital sound vs color. The analogies are downright amazing.

Lee Clawson

2/\V/\7 Studio

___________________________________________________________________________

Re: Blending ProPhoto Channels Into Other Images (was ProPhoto...)

Posted by: "Howard Smith"

Wed Nov 29, 2006 12:52 pm (PST)

Stephen,

Every one of your posts is an education! In fact you were the first one to impress me with the enormous utility of the Blend If tool, a tool that had mystified me until your posts encouraged me to look into how it worked. Now I use it frequently.

As for the image blending, I seem to have just happened across the one way to make it work the way it was described in my post. Using Convert to Profile doesn't change the appearance of the image, only its numbers. Whether it's then converted into CMYK from either Adobe RGB or from ProPhoto RGB the CMYK numbers will be the same. But if you make a duplicate and use Assign Profile to the duplicate to change it to ProPhoto RGB, the colors will change dramatically. Photoshop indicates that the original Adobe RGB profile has changed to a ProPhoto profile even though the numbers haven't changed. I'm curious about that, but then all I'm interested in doing is in changing the color intensity for blending purposes. When I take that (Assign Profile) duplicate and paste it into the original Adobe RGB image, the colors on the pasted layer remain the same as those in the original ProPhoto duplicate but Photoshop continues to show that the image, either in layers or blended, is still Adobe RGB. Now I can adjust the opacity and even the blending mode of the pasted layer to significantly improve the colors in my original Adobe RGB image. When this one is merged and converted to CMYK the colors will lose some of their intensity, but will nevertheless remain much more intense than in a CMYK version of the original image.

When the duplicate is converted to ProPhoto RGB with Convert to Profile, Curves adjustments will produce dramatically stronger effects than will the identical curves when applied to the original Adobe RGB image. This is nice, but what I'm trying to do is to intensify the colors without resorting to Curves. As a matter of interest, this Curves-adjusted, Convert-to-Profile ProPhoto image can be pasted into the Adobe RGB image and still retain its colors. Whether Curves-adjusted or simply produced with Assign Profile, the ProPhoto image pasted into the Adobe RGB file has similar effects on the appearance of the histogram.

Interested readers may now wonder how Assign Profile affects any subsequent editing. Simple answer: the only difference is that you are starting with more intense colors than you would have had if you had chosen to use Convert to Profile. Curves will work just the same, which is to say that any edits will produce more dramatic effects than you might expect when working with an image that has a smaller gamut profile. In other words, using Assign Profile instead of Convert to Profile just gives your image a color boost in the beginning. You have a ProPhoto file in either case.

Apply Image doesn't work in this example. Using Apply Image to paste the ProPhoto image into a blank layer above the original image layer only succeeds in changing the colors back to be the same as the original. In other words the ProPhoto layer and the Adobe RGB layer beneath it are identical in color. This is true regardless of whether I use Convert to Profile, Assign Profile, or Convert to Profile followed by Assign Profile (which now does not change the colors).

My odd technique doesn't seem to fit any theories, but does get the job done. After reading your informative post I'll have to look into it a little more deeply.

Thank you for all the valuable information.

Sincerely,

Howard Smith

___________________________________________________________________________

Re: Blending ProPhoto Channels Into Other Images (was ProPhoto...)

Posted by: Stephen Marsh

Thu Nov 30, 2006 12:11 am (PST)

Howard Smith

Every one of your posts is an education! In fact you were the first

one to impress me with the enormous utility of the Blend If tool, a

tool that had mystified me until your posts encouraged me to look into

how it worked. Now I use it frequently.

Thanks Howard, I only scratch the surface of blend if in my regular work, I really should try the AB of LAB more often.

But if you make a duplicate and use Assign Profile to the duplicate

to change it to ProPhoto RGB, the colors will change dramatically.

Photoshop indicates that the original Adobe RGB profile has changed to

a ProPhoto profile even though the numbers haven't changed. I'm

curious about that, but then all I'm interested in doing is in

changing the color intensity for blending purposes.

This is just assigning a known incorrect profile to achieve a desired result - a white lie if you will, known on this list as Dan's False Profile method (where one may also modify white point or gamma or primary values).

I may assign a A98 tag to a sRGB image or vice versa depending on whether I want to saturate and desaturate (hue also changes). Putting a ProPhoto label on A98 numbers takes this a whole lot further.

When I take that (Assign Profile) duplicate and paste it into the

original Adobe RGB image, the colors on the pasted layer remain the

same as those in the original ProPhoto duplicate but Photoshop

continues to show that the image, either in layers or blended, is

still Adobe RGB.

Ah, so you are blending composite data, not single channels - I was not sure. I was describing single channel blends, not composite. You are trying to pop colour, I was talking of adding detail, not colour in my pervious post.

You describe colour managing the file (numbers change so it looks the same), so that the colour appearance is kept as close as possible in the smaller space.

Obviously unless you softproof to a good output profile, monitor gamut clipping may not show any differnce between the two files, but the ProPhoto may have more extreme LAB numbers than the one that looks the same on the monitor.

Now I can adjust the opacity and even the blending mode of the

pasted layer to significantly improve the colors in my original Adobe

RGB image. When this one is merged and converted to CMYK the colors

will lose some of their intensity, but will

nevertheless remain much more intense than in a CMYK version of the

original image.

It will often depend on the image. But for some of them, I would convert from ProPhoto in a duped file to CMYK perceptual....then I would convert to sRGB from ProPhoto and then take the sRGB dupe to CMYK relcol render...then I would blend the ProPhoto->CMYK in luminance mode over the sRGB->CMYK image (or vice versa). Give it a go and let me know what you think, I find this is a good camera raw test image for detail in coloured and saturated areas:

http: //www.outbackphoto.com/workshop/NEF_conversion/nefconversion.html

Blending the green channel from say CIE RGB into the CMYK as a luminosity layer at lower opacity and blend if settings may be in order (perhaps unchecking some C,M, Y or K blending channels in advanced blending too).

And one can boost detail further on a dupe and blend it in with low opacity with the free Adaptive Equalize plug from:

http://www.reindeergraphics.com/ (look in the free section)

When the duplicate is converted to ProPhoto RGB with Convert to

Profile, Curves adjustments will produce dramatically stronger effects

than will the identical curves when applied to the original Adobe RGB

image. This is nice, but what I'm trying to do is to intensify the

colors without resorting to Curves.

Did you see the post from Lee Varis in the ProPhoto thread? As the data points are more spread, the moves are larger. It is only nice if you wish to make big moves.

Another way to 'pop' the image would be to use apply image on the AB in LAB or straight line curves in AB in LAB, these two methods are common for this list.

Yet another option, is to add a new adjustment layer, say curves, and then to not alter the curves but to use blending modes to alter contrast and colour. Overlay, softlight spring to mind...but play with them all! One can use the blend if sliders or an endpoint layer mask to stop this blowing out the highlights and shadows and only affect the midtones. You could do this on a dupe, merge it all down then copy this dupe back to the original file - and then blend the combined layer in color blend mode to only pop colour/saturation and not tone.

Apply Image doesn't work in this example.

You are relying on colour management to keep colour appearance similar for you method.

Apply image works for the opposite reason, it does not alter the colour values - which is why it is good for adding detail from a single channel, such as Wide Gamut RGB or CIE RGB, or ProPhoto RGB.

Regards,

Stephen Marsh.

___________________________________________________________________________

Re: Blending ProPhoto Channels Into Other Images (was ProPhoto...)

Posted by: "jerry_psimer"

Thu Nov 30, 2006 8:30 am (PST)

"Stephen Marsh"wrote:

Yet another option, is to add a new adjustment layer, say curves, and

then to not alter the curves but to use blending modes to alter

contrast and colour. Overlay, softlight spring to mind...but play with

them all! One can use the blend if sliders or an endpoint layer mask

to stop this blowing out the highlights and shadows and only affect

the midtones. You could do this on a dupe, merge it all down then copy

this dupe back to the original file - and then blend the combined

layer in color blend mode to only pop colour/saturation and not tone.

This is an approach that I use frequently. To even go a step further you can combine "empty" curve layer adjustments to combine the effects of various blend modes through the use of clipping groups. For Instance, you can use Overlay to Darken, or Multiply the luminosity of an image. There are unlimited options for correcting in this manner that allow for very fine control. This same concept can be carried across through the Apply Image command or Calculations for creating blending channels. The possibilities are endless when combined with other options like Blend If and Layer Masking and the use of "False Profiling".

Jerry P'Simer

___________________________________________________________________________

Re: Blending ProPhoto Channels Into Other Images (was ProPhoto...)

Posted by: "Howard Smith"

Thu Nov 30, 2006 2:06 pm (PST)

Stephen,

Thank for your continued guidance. I'm often overwhelmed by the amount of material you manage to cover in a single post! This one will take a little while to work through, but I'll be trying out everything you mentioned. You really should try to find time to write a book covering some of your knowledge of Photoshop. There seem to be fewer than half dozen members of the Forum who have done this, and I believe I have all of their books. While it once seemed that these few authors have covered just about everything in Photoshop-rendering most of my library irrelevant-you have so many fresh ideas that a book written by you would be a prized addition.

As a reminder to those Forum members who are hesitant to express their own thoughts, my own recent posts exposed my ignorance but at the same time gave me a much better understanding of some of the things that have puzzled me for years. You can learn a lot more from your mistakes than in always being right.

Howard Smith

___________________________________________________________________________

Re: Blending ProPhoto Channels Into Other Images (was ProPhoto...)

Posted by: "Wai-hong Chung"

Fri Dec 1, 2006 7:38 am (PST)

Hi Stephen Marsh,

Please note Howard Smith wrote :- "You really should try to find time to write a book covering some of your knowledge of Photoshop."

If you write such a book, I'll be the first one to buy it !

Best,

Wai-hong Chung from Hong Kong

___________________________________________________________________________

ProPhoto as Default Working Space

Posted by: "Raymond E. McKinley

Sun Dec 3, 2006 11:16 am (PST)

Hi Group

Here is an interesting look at 16bit printing, Pro Photo Working space etc. by Mike Chaney, creator of QImage.

http: //www.steves-digicams.com/techcorner/December_2006.html

Regards

Raymond E. McKinley

___________________________________________________________________________

Re: ProPhoto as Default Working Space

Posted by: Mark Segal

Sun Dec 3, 2006 3:29 pm (PST)

The first mistake is the omission to state that the best DSLRs capture at 12 bits, so we never get 16 to start with.

The second mistake is the omission to state what happens when files are downloaded from the CFcard, opened in say Adobe Camera Raw and converted say to PSD files. What Photoshop calls 16 bits is actually 15 bits (reducing levels from 65536 to 32768), but AFAIK the difference between what we start with (12 bits) and what we convert to (15 bits) is empty information. So we actually have 12 bits of real information, which creates 4096 useful levels, not 65536 levels.

The practical implication may be that when evaluating the advantages of greater bit depth to fill larger color spaces, the range of the fill is very much less at 4096 levels than it would be at ~65K or ~32K levels. Of course 4096 is still multiples more 256, so in principle may be beneficial in those cases where 256 is insufficient to prevent break-up in ProPhoto space.

Mark Segal

___________________________________________________________________________

PP5 and a comment

Posted by: "Mike Davis"

Mon Dec 4, 2006 5:30 pm (PST)

First, my PP5 arrived today from Amazon. Nice, big book, heavy and with a CD in the back. Looks like it will hold together after I've read it for the umpteenth time. Great job, Dan, and thanks. I'll squeal later after I've tried reading it. :-)

Second, I take issue with Rich Wagner's comments earlier:

sRGB is a standard for WEB use, but it makes a lousy standard for

other image uses. Making it "easy" for everyone by resigning every

image to sRGB would limit image quality for everyone to the lowest

common denominator. sRGB is a terrible color space for many uses, and

most professionals and certainly archivists would find that

unacceptable.

I use photography as a professional and as a hobbyist. 99% of my images sit easily within sRBG. I do not see it as a "standard", rather as my wife does when putting leftovers in containers for refrigerator storage. You don't use a one-gallon jar to store the remains of a can of green beans. If the image dictates the use of huge color spaces, by all means use them, but unless you are going to add a bunch of leftover meatloaf, corn, bread scraps and what-have-you to the jar of beans, there is nothing to be gained from using outsized containers. It doesn't degrade the image in any way when all original colors fit into a smaller color space.

So we now have inkjet printers that can exceed sRGB. That should require us all to find real world colors that can show them off? Perhaps that's partially responsible for the current trend of over-saturating images for "punch." There's an old saying: "Everything looks like grass when you have a lawnmower." Some of you guys are mowing weeds sticking up through cracks in the sidewalk.

Mike Davis

mldavis2 AT sbcglobal DOT net

http://www.pbase.com/mldavis2/

___________________________________________________________________________

Re: PP5 and a comment

Posted by: "Bob Frost"

Tue Dec 5, 2006 3:57 am (PST)

Mike,

Perhaps that's partially responsible for the current trend of

over-saturating

images for "punch."

Surely that trend started back in 1990 when Fuji introduced that horrible Velvia film?

Bob Frost.

___________________________________________________________________________

Re: PP5 and a comment

Posted by: "Werner Tschan"

Tue Dec 5, 2006 3:57 am (PST)

Mike Davis wrote:

I use photography as a professional and as a hobbyist. 99% of my

images sit easily within sRBG. I do not see it as a "standard", rather as my wife does

when putting leftovers in containers for refrigerator storage. You don't

use a one-gallon jar to store the remains of a can of green beans. If the

image dictates the use of huge color spaces, by all means use them, but

unless you are going to add a bunch of leftover meatloaf, corn, bread scraps

and what-have-you to the jar of beans, there is nothing to be gained from

using out sized containers. It doesn't degrade the image in any way when all

original colors fit into a smaller color space.

Total agreement..

So we now have inkjet printers that can exceed sRGB. That should

require us all to find real world colors that can show them off? Perhaps that's

partially responsible for the current trend of over-saturating images for

"punch."

It's done because we can do it. In Europe, the trend is away from over

saturated images.

There's an old saying: "Everything looks like grass when you have

a lawnmower." Some of you guys are mowing weeds sticking up through cracks

in the sidewalk.

Total agreement again.

Werner Tschan

professional photographer

___________________________________________________________________________

Re: PP5 and a comment

Posted by: "Ric Cohn"

Tue Dec 5, 2006 8:22 am (PST)

On Dec 5, 2006, at 2:20 AM, Bob Frost wrote:

Surely that trend started back in 1990 when Fuji introduced that horrible

Velvia film?

it's not the tools, it's how they're used. Someone can appropriate a technique and apply their style to it and it can be just the right thing. IMHO, the abominations happen when less talented people think the technique is their style-- and it's so easy to do too! Instant art at the push of a button.

Ric Cohn

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