Dan Margulis Applied Color Theory

Adobe RGB v. sRGB

   Date: Thu, 19 Feb 2004 01:13:37 -0000
   From: “Victoria Bampton”
Subject: AdobeRGB vs sRGB

Hi all!

I’m sorry - I’m sure this is a question that’s been asked many times, but I’ve trawled back through the archives, and I can’t find what I’m looking for.  I’ve been lurking on the list for a long time, and I’m sure that you’re the best people to help me, so thanks in advance...

We have a professional portrait/wedding photographic studio, and are in the process of changing to digital.  The camera we’ve gone for is a Canon 10d. Our labs print to wet-process photographic paper, and ask for AdobeRGB files.  As far as I understood, we are therefore best setting the camera to AdobeRGB, and keeping that colour space right the way through the workflow. But we were told today by another professional that we should be using sRGB and then converting to AdobeRGB.  Which is best, please???

Sorry for such a basic question!  Many thanks for your help.

Regards

Victoria
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   Date: Wed, 18 Feb 2004 20:30:59 -0800
   From:Paul D. DeRocco
Subject: RE: AdobeRGB vs sRGB

First of all, I don’t understand why any professional lab should be unable to handle _any_ color space, as long as there’s an embedded profile. You’d think the expensive equipment they use would be able to keep up with the lowly stuff that we mere mortals use, like Photoshop, Epson printers, and so on.

But the answer to that question is that you might as well shoot Adobe RGB. There’s no point in shooting sRGB, which doesn’t allow quite such saturated greens (and cyans and yellows), and then converting to Adobe RGB.

However, if you shoot JPEGs in the camera, and use the Adobe RGB setting on the camera, be aware that it does not actually embed an Adobe RGB profile in each image. To make sure that the lab gets it right, you really should embed the profile. You can either run the JPEG through a photo editor like Photoshop, and tell it to embed the proper profile, or (better) you can shoot in raw mode and tell the conversion software you want Adobe RGB, in which case it will do the proper embedding.

Ciao,               Paul D. DeRocco
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   Date: Wed, 18 Feb 2004 22:36:33 -0800
   From: J Walton
Subject: RE: AdobeRGB vs sRGB

You may as well leave it in Adobe RGB if you have to deliver that.  I’m not sure what the advantage of sRGB would be if you are delivering RGB files.
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   Date: Thu, 19 Feb 2004 07:27:27 -0500
   From: Laurentiu Todie
Subject: Re: AdobeRGB vs sRGB

The lab should have a profile for each machine they use for printing. If you have a calibrated monitor, you should convert to that color space (after retouching and saving a version in AdobeRGB) to see what the picture will look like printed.

Laurentiu
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   Date: Thu, 19 Feb 2004 07:45:09 -0500
   From: “Annette Murray”
Subject: RE: AdobeRGB vs sRGB

The lab should have a profile for each machine they use for printing.
If you have a calibrated monitor, you should convert to that color space
(after retouching and saving a version in AdobeRGB) to see what the picture
will look like printed.

Convert or Assign??

Annette Murray
Prepress and Color Consultant

ANRO Inc.
222 Lancaster Ave.
Devon, PA 19333
Website: ANRO.com

800.355.2676 x241
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   Date: Thu, 19 Feb 2004 09:12:15 -0500
   From: Jim Rich
Subject: Re: AdobeRGB vs sRGB
 
Laurentiu,

I am not sure I understand your comment.

Are you saying  to use the monitor profile for a conversion?

Or are you saying that each computer will have a monitor profile that controls the monitors hardware. And that during the process of capturing an image you will assign  a scanner profile and then convert to an Adobe working space then do your retouching.  And all the while in that process the monitor  will maintain a consistent view of the color because the monitor is using  monitor profile that controls the monitor.
 
Or are you saying something  else?

Jim Rich
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   Date: Thu, 19 Feb 2004 12:08:47 -0400
   From: “Ellie Kennard”
Subject: RE: AdobeRGB vs sRGB

Neither convert nor assign, but use soft proof (View - Proof and then use the supplied profile for soft proofing).

If you open a duplicate without soft-proofing, you can then compare to make your colour corrections.

Ellie
 
—
Ellie Kennard
Innovative Imaging Studio
http://www.iiStudio.com
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   Date: Thu, 19 Feb 2004 14:25:34 -0500
   From: Laurentiu Todie
Subject: Re: AdobeRGB vs sRGB

Your camera assigned the AdobeRGB space to the shot; you convert for printing only.
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   Date: Thu, 19 Feb 2004 14:40:29 -0500
   From: Laurentiu Todie
Subject: Re: AdobeRGB vs sRGB

Jim, The best use of a monitor profile for humans is to assign to... screen shots : )

Laurentiu
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   Date: Thu, 19 Feb 2004 12:09:05 -0800
   From: “Michael Plack”
Subject: Re: AdobeRGB vs sRGB

  Victoria,

  AdobeRGB is a larger colorspace than sRGB.  Therefore, it stands to reason that if you were to convert from the larger to the smaller space, no colors would be lost.  However, if you were to convert from the smaller to the larger colorspace, interpolation would be required resulting in a loss of color fidelity.  Therefore, for your situation, shooting in AdobeRGB would be the way to go (unless you chose to shoot in RAW mode).

  BTW, you mentioned that you were told by another professional that shooting in sRGB and converting to AdobeRGB would be the appropriate workflow.  Was this ‘professional’ another photographer, or perhaps, hopefully, your accountant?

  Michael Plack
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   Date: Thu, 19 Feb 2004 22:15:04 -0000
   From: Victoria Bampton
Subject: RE: AdobeRGB vs sRGB

Thanks for all the replies everyone.

You’ve confirmed exactly what I’d previously understood from this list... but now I have the evidence from you to show my father that he was told the wrong info.  What worries me more, is that this ‘professional’ runs Digital Photography and Photoshop for Pro Photographers courses in the UK, is very well known, but has some very off-the-wall ideas on colour management. Having said that, my father is very new to digital, and therefore possibly may have misunderstood.  But either way, thanks for the info.  This is a great list!

Victoria Bampton
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   Date: Fri, 20 Feb 2004 12:45:47 -0500
   From: Dan Margulis
Subject: RE: AdobeRGB vs sRGB

Michael Plack writes,

AdobeRGB is a larger colorspace than sRGB.  Therefore, it stands to reason
that if you were to convert from the larger to the smaller space, no colors
would be lost.

Precisely the opposite is true. The larger colorspace can define colors that the smaller one can’t touch. This is always the problem area in conversions, because no algorithm can make a correct decision every time on how to handle out-of-gamut colors. It is always easier to go from smaller to larger. This is particularly so in the present case where Victoria is presumably (because her work doesn’t seem to feature particularly brilliant colors) not attempting to access colors that exist in Adobe RGB but not in sRGB.

However, if you were to convert from the smaller to the
larger colorspace, interpolation would be required resulting in a loss of
color fidelity.

The larger colorspace can’t support all of the subtle transitions of the smaller one, true. But even if this were a real-world problem (which it isn’t) it would be inherent in the definition of Adobe RGB, not having anything to do with the conversion process.
 
As for “interpolation”, this in principle might happen going from the larger to the smaller space, but in practice it again isn’t a problem. The files are being cross-referenced to LAB, which, as part of the process,is generating valid intermediate data, not random interpolations.

I’ve run lots of multiple sRGB>Adobe RGB>sRGB conversions. It isn’t quite as lossless as sRGB>LAB>sRGB, but there’s no realistic danger in doing it. Adobe RGB>sRGB>Adobe RGB can be quite risky.

I don’t see that there’s any reason in Victoria’s case to do anything other than the obvious, which is to capture the image in whichever RGB seems to capture it best, and then convert it later or not as the case may be.

Dan Margulis
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   Date: Fri, 20 Feb 2004 10:29:57 -0800
   From:Paul D. DeRocco
Subject: RE: AdobeRGB vs sRGB

From: Dan Margulis

I’ve run lots of multiple sRGB>Adobe RGB>sRGB conversions. It
isn’t quite as lossless as sRGB>LAB>sRGB, but there’s no
realistic danger in doing it.

Actually, if you use the Perceptual rendering intent, that will desaturate your greens a bit, because the second conversion compresses the gamut a bit in order to make room for all those nonexistent colors that are out of gamut for sRGB.

Ciao,               Paul D. DeRocco
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   Date: Fri, 20 Feb 2004 20:29:37 -0000
   From: Victoria Bampton
Subject: RE: AdobeRGB vs sRGB

Hi Dan

Thanks for your input.  So am correct in thinking, therefore, that as our lab want AdobeRGB files, and our working space is always AdobeRGB, that is would make the most sense to capture in AdobeRGB too?  We never use sRGB for anything, so there isn’t any benefit to capturing in sRGB is there?  Are we not better to avoid converting at all if possible?

Thanks for the clarification.

Victoria
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   Date: Sat, 21 Feb 2004 00:35:56 -0000
   From: “Robert Catto”
Subject: Re: AdobeRGB vs sRGB

Hi Victoria, sorry to throw a cat among the pigeons on this one;

Perhaps the reason you were told to shoot in sRGB & convert was due to an article on the web, which I’ve read (but can’t locate just at the moment), where Chuck Westfall of Canon USA recommended exactly that.

It was specifically relating to the 10D, and essentially stated that while the colour space is indeed larger, the camera is perhaps ‘better’ at rendering in sRGB?  I can’t give you a better description than that at the moment, I’m afraid, but I definitely remember coming away with that impression.

I’m guessing it was on Rob Galbraith’s forum (http://www.robgalbraith.com) as Chuck often writes there; and I’m sure I’ll find it as soon as I hit send on this message!
R
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   Date: Sat, 21 Feb 2004 21:13:01 -0000
   From: “dmargulisnj”
Subject: Re: Adobe RGB vs. sRGB

Victoria writes,

Hi Dan
Thanks for your input. So am correct in thinking, therefore, that as
our lab want AdobeRGB files, and our working space is always
AdobeRGB, that is would make the most sense to capture in
AdobeRGB too? We never use sRGB for anything, so there isn’t
any benefit to capturing in sRGB is there? Are we not better to
avoid converting at all if possible?

I wouldn’t worry about the conversion. It was suggested elsewhere (I don’t know this myself) that the particular camera produces a better quality capture in sRGB than in Adobe RGB. You can certainly experiment to find out whether this is so.

I’d recommend staying away from Adobe RGB in any of the following cases:
1) Your work commonly showcases brilliant colors;
2) CMYK is your principal destination;
3) Your RGB files are likely to be handled by strangers.

It seems that none of these factors apply in your case, so if you’re satisfied that the capture quality in Adobe RGB  is good, then your logic is correct, and you should go Adobe RGB all the way.

Dan Margulis
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   Date: Sat, 21 Feb 2004 19:00:42 -0500
   From:Russell Proulx
Subject: Re: AdobeRGB vs sRGB

Victoria,

I find that using a larger colour space such as AdobeRGB allows one to adapt their files to a wider variety of output mediums. Some output methods may offer access to colours that would no longer exist once a file is converted to sRGB. Why not capture as wide a colour gamut at the shooting stage. Some even recommend scanning in wide gamut colourspaces such as ProPhotoRGB and saving this as a sort of ‘master’ for the day that a wide gamut colour printer comes around.

I find it interesting that your lab requests only AdobeRGB files. Most digital-to-photopaper printers (Noritzu, Pictrography, Frontier, etc..) are manufactured to reproduce the sRGB colourspace which represents what 99.9% of consumer digital cameras use, and the consumer market is what drives the industry.

If your lab wants AdobeRGB then give them AdobeRGB. The problem I’ve seen here in Montreal is that the workflow of too many consumer labs is to ignore the embedded colourspace of the original and simply output it as if the it was in sRGB (the consumer standard). Even some pro labs have been slow to grasp that RGB comes in different flavours and they need to convert from the clients colourspace to whatever their printer expects (or better still convert to the printer profile). The safest thing to do here is to convert to sRGB before sending the file to a lab so, even if they don’t check, it’ll at least be in the same colourspace of 99% of their clients and will print just fine. I have to wonder how your local pro lab is dealing with the fact that most digital cameras (except high-end models) can ONLY shoot in sRGB? Are they turning these clients away? (I think not).

I suspect that your lab ‘thinks’ they’re getting more colours out of their equipment by recommending AdobeRGB from clients who have the option. But they must certainly also accept sRGB. I’m convinced the lab is making a recommendation only and would deal with whatever flavour of RGB an image is in and output it accordingly.

Hope this helps shine some light on the subject :-)

Russell Proulx
Montreal, Canada
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   Date: Sat, 21 Feb 2004 21:17:14 -0500
   From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB

From: “dmargulisnj” <
I’d recommend staying away from Adobe RGB in any of the
following cases:
1) Your work commonly showcases brilliant colors;
2) CMYK is your principal destination;
3) Your RGB files are likely to be handled by strangers.

Dan,

Is your reasoning for number 1 that the profile might be ignored by someone further down the line? By my understanding, brilliant colors will be more easily contained and handled by the larger AdobeRGB space rather than sRGB.

john castronovo
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   Date: Sun, 22 Feb 2004 10:16:51 -0600
   From: “Ronal Walraven”
Subject: Subject: Re: Adobe RGB vs. sRGB / Assign vs Convert

As a side question. Do digital cameras convert the image capture to sRGB or Adobe RGB color space (remapping out of gamut pixels) or just assign the color space to the image (not remapping any pixels)? This question is not for a specific camera model but for digital cameras in general or is the answer camera model specific?

Ronal’ Photography & Digital Imaging
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   Date: Sun, 22 Feb 2004 09:09:22 -0800
   From: David Cardinal
Subject: Re: Adobe RGB vs. sRGB / Assign vs Convert

As a side question. Do digital cameras convert the image
capture to sRGB or Adobe RGB color space (remapping out of
gamut pixels) or just assign the color space to the image
(not remapping any pixels)? This question is not for a
specific camera model but for digital cameras in general or
is the answer camera model specific?

The answer is camera specific. Generally there are (at least) 4 scenarios:

* Cameras which both convert the image to a colorspace & correctly add the ICC profile to the image. The Nikon D2H, and the post-firmware-updated D1X and D1H are examples.

* Cameras which convert the image to a colorspace but don’t tag the image. Pre-firmware updated Nikon D1X and D1H are examples of this, along with (as I recall) the Canon 1D.

* Cameras which shoot in sRGB but don’t add it as a profile tag. Many consumer cameras fall into this category. Photoshop will still often open these images as being from sRGB based on some default behaviors for an EXIF “colorspace” flag, which is not the same thing as a real profile being embedded.

* Cameras which don’t shoot in any particular colorspace. The original D1 is an example (it turns out to have been factory calibrated on NTSC monitors, so that was a close approximation, but Nikon never mentioned that until many of us wrote about it as a “tip”), as are most consumer cameras over a year or two old.

The big caveat is of course how well the cameras do the conversion. High-end models have gotten quite good at it. I suspect many consumer cameras that purport to shoot into sRGB aren’t as close. Even the pro models benefit from a custom profile, as of course the conversion logic is model specific but not specific to your particular camera.

—David
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   Date: Sun, 22 Feb 2004 09:55:19 -0800
   From:Paul D. DeRocco
Subject: Re: Adobe RGB vs. sRGB / Assign vs Convert

I’ve never found the color from any digicam, including my 10D, to be so accurate that one could even reasonably say whether an image supposedly in a particular color space was actually in that color space, in any meaningful sense. I always always always have to play with the color, not to mention every other tweak under the sun, to turn the raw material into a nice-looking finished product.

So unless you’re using the camera to provide evidence of what precise color something was for a court case, I wouldn’t worry a whole heck of a lot about it. Just eyeball it afterwards.

Ciao,               Paul D. DeRocco
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   Date: Sun, 22 Feb 2004 14:28:39 -0500
   From:Russell Proulx
Subject: Re: Subject: Re: Adobe RGB vs. sRGB / Assign vs Convert

On 22 Feb 2004 at 10:16, Ronal Walraven wrote:

As a side question. Do digital cameras convert the image capture to sRGB or
Adobe RGB color space (remapping out of gamut pixels) or just assign the
color space to the image (not remapping any pixels)? This question is not
for a specific camera model but for digital cameras in general or is the
answer camera model specific?

The RAW capture of the CCD or CMOS camera sensor is converted to sRGB or AdobeRGB colourspace. If you can save your image in a RAW format then, with the right software, you can convert it to other colourspaces as well. ie: The Adobe PhotoshopCS RAW convertor offers output to your choice of AdobeRGB, ColormatchRGB, sRGB and ProPhotoRGB and the RGB pixel values are adjusted accordingly.

Russell
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   Date: Sun, 22 Feb 2004 17:03:41 EST
   From: Dan Margulis
Subject: Re: Re: Adobe RGB vs. sRGB

John Castronovo writes,

Is your reasoning for number 1 that the profile might be ignored by someone
further down the line?

No.

By my understanding, brilliant colors will be more easily contained and
handled by the larger AdobeRGB space rather than sRGB.

The problem is that unless considerable care is taken the brilliant colors are likely to be out of the gamut of whatever the output device is. There are crutches (like a perceptual rendering intent) but basically in such situations the choices are to become an expert color corrector to restore what’s been lost when the file is converted, or to accept second-quality color.

Dan Margulis
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   Date: Sun, 22 Feb 2004 22:33:43 -0500
   From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB

So then it’s your advice to the novice to stick with sRGB whether the subject has a wide gamut or not? It certainly is safer all around, but some colors will suffer. Possibly the trade off is worth it.

john castronovo
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   Date: Sun, 22 Feb 2004 21:00:25 -0800
   From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB

From: john c.

So then it’s your advice to the novice to stick with sRGB whether the
subject has a wide gamut or not? It certainly is safer all
around, but some
colors will suffer. Possibly the trade off is worth it.

That’s up to you, but remember that the colors you lose are so saturated that you can’t even see them on typical monitors. And most printers that can reach them at all can only do so in the midtones. It’s only green, and by extension yellow and cyan, that are affected, since Adobe RGB and sRGB have the same red and blue primaries.

Ciao,               Paul D. DeRocco
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   Date: Sun, 22 Feb 2004 23:05:43 -0800
   From: Stephen Ray
Subject: Re: Re: Adobe RGB vs. sRGB

I’ve asked this question here before and I know Dan has already answered:

What in our natural world contains colors outside of the sRGB color space?

If there are PRACTICALLY no colors outside that space, why open a can of worms by working in a space that’s contains an even wider gamut?

I’ve seen demonstrations where Adobe98 was used and resulted in a more brilliantly colored Epson print over the sRGB version. All these demonstrations were of photographs. Bright, but solitary in their use. My experience tells me that one with such prints would have a difficult or impossible time reproducing that color on typical presses or photo devices if they were required, and that’s often the case.

I find designers and photographers who are using Adobe98 are far more disappointed when they see output from service bureaus that those using sRGB. Usually the first thing they learn is the bureau has no device to image that gamut. If they can possibly  soft-proof, they’re shocked at the gamut reduction and begin making phone calls asking if what they see is correct.

The best Epson prints I’ve seen were color managed to mimic a 3M Match Print which is a very small gamut compared to Adobe98 or sRGB. The inkjet matched actual 3M, the original photo transparency, some Pantone samples, stocastic press work, Xerox, and Lambda display all in their exhibit booth. A PRACTICAL use of color gamut.

I find sRGB more practical than Adobe98 and I still have huge issues recommending it!

-Stephen Ray
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   Date: Mon, 23 Feb 2004 08:46:27 -0500
   From: Terry Wyse
Subject: Re: Re: Adobe RGB vs. sRGB

On Feb 23, 2004, at 12:00 AM, Paul D. DeRocco wrote:

It’s only green, and by
extension yellow and cyan, that are affected, since Adobe RGB and sRGB
have the same red and blue primaries.

Humm...really? Try taking an image of people/fleshtones that’s in sRGB and then ASSIGN AdobeRGB to that same image. The fleshtones will be bleeding red and oversaturated. Since the red/blue primaries are the same and the gamma is identical, then what is going on?

Terry
_____________________________
WyseConsul
Color Management Consulting
704.843.0858
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   Date: Mon, 23 Feb 2004 06:25:02 -0800
   From: “Michael Stokes”
Subject: RE: Re: Adobe RGB vs. sRGB

For color gamut, rain forest foliage (the really nice blue/green Spring leaves, not late Fall yellowing ones), red/orange Japanese maple leaves, human blood. If you consider textiles “natural” then most dark saturated velvets...and many more.

For dynamic range, technically the sRGB standard targets 80-100 cd/m^2 (typical CRT) and thus leaves out a lot of high dynamic range imagery.

The family of P22 phosphor set which HDTV is based on which in turn sRGB is directly derived is limited to what it is capable of.

Michael Stokes, Microsoft Corporation
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   Date: Mon, 23 Feb 2004 07:26:43 -0700
   From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB

on 2/23/04 12:05 AM, CitizenRay wrote:

What in our natural world contains colors outside of the sRGB color space?
 
Natural world as seen by what? Humans? Look at sRGB on top of a plot of CIE:LAB and you1ll see how tiny a color space it is compared to what we can see.

Now plot sRGB on top of even CMYK Ink on paper and it1s not fully contained. Take a 7 color ink jet and there are all kinds of colors outside of sRGB.

Do you want to capture and use those colors? If so, you do NOT want sRGB. If you don1t care, it1s fine and dandy.

Andrew Rodney
http://www.digitaldog.net
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   Date: Mon, 23 Feb 2004 10:28:18 -0500
   From:Russell Proulx
Subject: RE: Re: Adobe RGB vs. sRGB

On 22 Feb 2004 at 21:00, Paul D. DeRocco wrote:

 the colors you lose are so saturated
that you can’t even see them on typical monitors.

I teach a Photoshop Class at a local college and can easily demonstrate loss. Create a rainbow in in AdobeRGB and then convert to sRGB (not the other way around) and even cheap monitors will show a loss.

On 23 Feb 2004 at 8:46, Terry Wyse wrote:

Try taking an image of people/fleshtones that’s in sRGB and
then ASSIGN AdobeRGB to that same image.

That’s a incorrect use of colour management. You need to CONVERT the image from one space to another. Otherwise the RGB numbers result in nonsense on the screen which is what you’re seeing. All you’re proving is that RGB numbers for the same colour are different in different colour spaces. When converted the numbers are remapped to their closest equivalent and the difference from sRGB to AdobeRGB will be ‘no difference at all’.

On 22 Feb 2004 at 23:05, CitizenRay wrote:

I’ve seen demonstrations where Adobe98 was used and resulted in a more
brilliantly coloured Epson print over the sRGB version. All these
demonstrations were of photographs. Bright, but solitary in their use.
My experience tells me that one with such prints would have a difficult
or impossible time reproducing that color on typical presses or photo
devices if they were required, and that’s often the case.

Almost every RGB image gets hurt somewhat when converting to SWOP CMYK, especially the blues. You already know this. I don’t feel better off by having a ‘dumbed down’ RGB so I lose even less in the conversion to CMYK. Why not just scan in CMYK and avoid all those needless colours altogether? You said it yourself “resulted in a more brilliantly coloured Epson print over the sRGB version. All these demonstrations were of photographs.” Most photographers are replacing film with digital and want to keep as many colours as they had before. Many photographers have always been disappointed with how some of their images die on the press. That’s the reality of that limited gamut. But there are many output options with larger gamuts than a press and photographers need to make best use of these print options as well. This includes multi-ink inkjet printers and traditional silver photo prints which both offer better colour than CMYK. And their gamuts will only get larger due to competition.

Photographer’s need to use a compromise colourspace that makes the best use of diverse output technologies. Some find that AdobeRGB works best for them or even larger colourspaces (ProPhotoRGB). My advice to photographers is to learn to do their own CMYK conversions (take Dan’s class, read his books!) and thus be much more accurately aware of what’will be lost and how to deal with it. I don’t see how someone working in sRGB will be any less disappointed if they expect to reproduce exactly what they see on their screens on a press.

Russell Proulx
Montreal
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   Date: Mon, 23 Feb 2004 09:47:56 -0800
   From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB

From: Terry Wyse

Humm...really? Try taking an image of people/fleshtones that’s in sRGB
and then ASSIGN AdobeRGB to that same image. The fleshtones will be
bleeding red and oversaturated. Since the red/blue primaries are the
same and the gamma is identical, then what is going on?

Actually, the gamut is larger in the red direction, but only in the 3D space where luminance is included. Adobe RGB and sRGB have the same xy values for red, but Adobe has a higher Y value, which means you can represent brighter reds, not more saturated ones. When I compare this to various printer profiles, the extra red area doesn’t overlap with any of them. For instance, the Epson 2200 on glossy paper exceeds Adobe RGB in the brighter yellows, midtone magentas, and darker cyans, but can’t do particularly bright reds.

Also, by the way, the gamma isn’t identical. Adobe RGB is a true 2.2 curve, while sRGB is about 2.3 or 2.4 with a linear segment at the bottom.

Ciao,               Paul D. DeRocco
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   Date: Mon, 23 Feb 2004 09:14:49 -0800
   From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB

From: CitizenRay

What in our natural world contains colors outside of the sRGB color space?

Various paints and cloth dyes are very saturated, and I think even occasionally some flower colors. Not a whole heck of a lot, though, and in reality desaturating these colors doesn’t necessarily destroy the aesthetic effect of the image.

I find designers and photographers who are using Adobe98 are far more
disappointed when they see output from service bureaus that those using
sRGB. Usually the first thing they learn is the bureau has no device to
image that gamut. If they can possibly  soft-proof, they’re shocked at the
gamut reduction and begin making phone calls asking if what they see is
correct.

It’s certainly pointless to increase the size of your editing gamut beyond what your monitor can do, if your printer can’t do it. Since I make inkjet prints, I often use Adobe RGB.

Ciao,               Paul D. DeRocco
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   Date: Mon, 23 Feb 2004 10:46:56 -0800
   From: Steven Barton
Subject: Re: Re: Adobe RGB vs. sRGB

From: “Russell Proulx”

My advice to photographers is to
learn to do their own CMYK conversions (take Dan’s class, read his books!)
and thus be much more accurately aware of what’will be lost and how to deal
with it. I don’t see how someone working in sRGB will be any less
disappointed if they expect to reproduce exactly what they see on their
screens on a press.

Converting images to CMYK well can be quite an art. It certainly requires an investment in time and learning. Can the photographer charge extra for this additional service and higher level of control?

Steven Barton
Imaging Sciences & Partners
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   Date: Mon, 23 Feb 2004 13:50:29 -0500
   From: Terry Wyse
Subject: Re: Re: Adobe RGB vs. sRGB

On Feb 23, 2004, at 10:28 AM, Russell Proulx wrote:

That’s a incorrect use of colour management. You need to CONVERT the image
from one space to another. Otherwise the RGB numbers result in nonsense on
the screen which is what you’re seeing. All you’re proving is that RGB
numbers for the same colour are different in different colour spaces. When
converted the numbers are remapped to their closest equivalent and the
difference from sRGB to AdobeRGB will be ‘no difference at all’.

Of course it’s a “wrong” application of color management but in the context of what I was responding to, it was a valid statement. The original statement was something to the effect of “the only difference between sRGB and AdobeRGB is the green extension since the red/blue chromaticities are identical”. I was only trying to demonstrate that there’s more going on than simply having a different green coordinate. Not that I can tell you WHY exactly that is the case, only that the difference between the two profiles goes beyond simple chromaticities and gamma.

Terry
_____________________________
WyseConsul
Color Management Consulting
704.843.0858
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 11:30:37 -0800
   From: Stephen Ray
Subject: Re: Re: Adobe RGB vs. sRGB

From: “Michael Stokes”

For color gamut, rain forest foliage (the really nice blue/green Spring
leaves, not late Fall yellowing ones), red/orange Japanese maple leaves,
human blood. If you consider textiles “natural” then most dark saturated
velvets...and many more.<<

Do you actually have, or know of, LAB values for these and where they fall regarding the sRGB space? Granted, anyone would be hard pressed to measure velvet, blood, or exotic foliage.

For dynamic range, technically the sRGB standard targets 80-100 cd/m^2
(typical CRT) and thus leaves out a lot of high dynamic range imagery.

Is gamut not the same as dynamic range?

I’m afraid I bear a trait from my mother who was from Missouri, the Show Me state.

-Stephen Ray
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 12:03:56 -0800
   From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB

From: Russell Proulx

I teach a Photoshop Class at a local college and can easily demonstrate
loss. Create a rainbow in in AdobeRGB and then convert to sRGB (not the
other way around) and even cheap monitors will show a loss.

It’s certainly true that some monitors can display colors outside sRGB, but most not by much. (My LCD, not at all.) My guess is that you’re doing the conversion in either Perceptual or Relative Colorimetric mode. If the former, the color management engine will desaturate even some of those Adobe RGB colors that theoretically fit within sRGB, just to make room for the extended colors that don’t fit. It does this even if those colors don’t actually exist in the image. This is, I believe, a nonlinear desaturation, not as brutal as merely assigning sRGB, but it does affect in-gamut colors.

If you try it in Relative Colorimetric mode, there is still a white point change between the two color spaces, which means that some colors still need to be pushed around to adapt to the different white space. I wonder if you see the same degradation in Absolute Colorimetric mode.

An odd quirk that most people may have not noticed is that if you create an image with saturated greens in sRGB, and then convert it to Adobe RGB, the greens will get slightly duller. Counterintuitive? That’s because you’re actually seeing not the real colors but the colors after converting to the monitor color space. If you’ve selected the Perceptual rendering intent, it thinks it has to squeeze the color space more when you display an Adobe RGB image than when you display an sRGB image, even though your Adobe RGB was just converted from sRGB and doesn’t have any of those super-saturated colors.

I suppose this happens with printers as well. Try to use a color space that isn’t hugely out-of-range for the printer, or stay away from Perceptual mode, or better yet, soft proof if you’re lucky enough to have printer profiles that do that well.

Ciao,               Paul D. DeRocco
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 15:20:03 -0500
   From:Russell Proulx
Subject: Re: Re: Adobe RGB vs. sRGB

On 23 Feb 2004 at 10:46, Steven Barton wrote:

Converting images to CMYK well can be quite an art. It certainly requires an
investment in time and learning. Can the photographer charge extra for this
additional service and higher level of control?

I do, and it’s increased my bottom line. I can give clients work that they can rely on and charge more than I previously did for film and processing (which I had to pay to someone else). It also insures that my images won’t suffer at the hands of too may graphic artists who still don’t know what they’re doing with hi-rez images. I also supply images in RGB for those who do know what they’re doing.

Russell Proulx
Montreal
___________________________________________________________________________
 
  Date: Mon, 23 Feb 2004 12:56:09 -0800
   From: Stephen Ray
Subject: Re: Re: Adobe RGB vs. sRGB

Andrew Rodney wrote:

Natural world as seen by what? Humans? Look at sRGB on top of a plot of
CIE:LAB and you1ll see how tiny a color space it is compared to what we can
see. Now plot sRGB on top of even CMYK Ink on paper and it1s not fully contained.
Take a 7 color ink jet and there are all kinds of colors outside of sRGB.
Do you want to capture and use those colors? If so, you do NOT want sRGB. If
you don1t care, it1s fine and dandy.<<

Andrew,

We all know we can SEE huge extremes of color but only use a very small portion of the range with both our eyes and in print. We can’t really differentiate millions of blended tones and inked prints only really need thousands. (This reminds of working with Kai Krause and portraying continuous tone with 256 dithered colors on Ektachrome just to prove a point.)

My notion is much like that of an audio engineer. We use compression to make the product palatable. The garage band burns a CD with dynamics so extreme it will never pass RIAA specs to get to the air waves. A photographer or designer uses Adobe98 across all their Adobe apps and images a fabulous comp on their Epson only to find no vendor in their hemisphere can match the color. Compression is virtuous at times.

Yes, capturing everything I can but I wouldn’t start or stop at Adobe98 unless I had no choice. Using a work space is another issue and for me, that’s not Adobe98.

Stephen Ray
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 14:24:42 -0700
   From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB

on 2/23/04 1:03 PM, Paul D. DeRocco wrote:

It’s certainly true that some monitors can display colors outside sRGB, but
most not by much.

I1ve actually got a display (from Mitsubishi) that displays 98% of the Adobe RGB gamut! It1s a pre-production unit but the point is, this is technically doable. Funneling color into a tiny colorspace based upon the notion that all display and output devices are as tiny as sRGB is really painting yourself into a big corner.

Andrew Rodney
http://www.digitaldog.net
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 14:04:19 -0800
   From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB

From: Andrew Rodney

I1ve actually got a display (from Mitsubishi) that displays 98% of the Adobe
RGB gamut! It1s a pre-production unit but the point is, this is technically
doable. Funneling color into a tiny colorspace based upon the notion that
all display and output devices are as tiny as sRGB is really painting
yourself into a big corner.

Is this monitor something I ought to look into buying, or is it going to be some expensive monster like the Barco?

Ciao,               Paul D. DeRocco
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 17:41:28 -0700
   From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB

on 2/23/04 3:04 PM, Paul D. DeRocco wrote:

Is this monitor something I ought to look into buying, or is it going to be
some expensive monster like the Barco?

Not released yet and it will be inexpensive!

Andrew Rodney
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 22:28:55 -0500
   From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB

From: “Andrew Rodney”

Funneling color into a tiny colorspace based upon the notion that
all display and output devices are as tiny as sRGB is really painting
yourself into a big corner.

Don’t you mean a little corner?

 I just wanted to jump in here to say that I agree with you. We never had a problem working in DonRGB (for many years now), and I don’t think that I would say that if we were working in sRGB. If we all limited ourselves to that smallest of color spaces that was common to ALL devices, there would be few surprises - quite safe, but certainly not beautiful color.

john castronovo
___________________________________________________________________________

   Date: Mon, 23 Feb 2004 23:08:37 EST
   From: Dan Margulis
Subject: Re: Re: Adobe RGB vs. sRGB

John Castronovo writes,

So then it’s your advice to the novice to stick with sRGB whether the
subject has a wide gamut or not? It certainly is safer all around, but some
colors will suffer. Possibly the trade off is worth it.

For a total novice, it’s probably best to do what the majority does. sRGB has clearly become the industry default over the last couple of years.  Anybody who doesn’t have a good grasp of what RGB definitions are (and total novices probably don’t) shouldn’t be messing with Adobe RGB.

For people who are not particularly skilled with color, but are shrewd enough to avoid any possibility of other people misinterpreting their files, Adobe RGB is a good choice. Although in theory it shouldn’t matter, in practice the use of Adobe RGB will favor relatively more colorful files, which are generally a good thing.

I think that Adobe RGB is not particularly suitable for most intermediate users. One of the biggest issues that the professional photographers who attend my classes come in with is loss of detail in brightly colored areas. Usually, this is an Adobe RGB problem. I just got back from an on-site where the images were digital captures of flowers, and CMYK output was the only consideration. That type of scenario screams out for something other than Adobe RGB.

Expert users know the advantages and disadvantages of using Adobe RGB and are well positioned to decide whether it makes sense given their own workflow. Expert users are also ready and willing to assign an sRGB profile to an Adobe RGB image where necessary, or vice versa. In this area, I agree with everything that Russell Proulx has been posting.

Dan Margulis
___________________________________________________________________________

   Date: Tue, 24 Feb 2004 10:35:56 -0000
   From: Victoria Bampton
Subject: RE: Re: Adobe RGB vs. sRGB

Hello all!

I seem to have opened a can of worms on this one!  Everyone has a different opinion, and all have good reasons for that opinion.  Are you trying to confuse me now??

Ok, so having spent the last 3 years following this list closely, and studying Dan’s book in detail (Dan, how about doing a course in the UK?), so I’ve managed to follow the debate fairly well.  I understand which colours are compressed/lost in sRGB vs AdobeRGB, and the benefits of not capturing detail that can’t be printed/shown on screen, but considering our lab want AdobeRGB and we’ve used AdobeRGB as our working space for the last 4 years with no problems, what would be the benefits of capturing in sRGB, only to later convert and therefore have to interpolate info?  I’d be really interested to read that article that Robert mentioned by Chuck Westfall - I couldn’t find it.

Dan, what makes you say that sRGB has become the industry default?  In the UK, I haven’t yet come across a pro lab who don’t want AdobeRGB.  Is this just a case of they don’t yet understand, or are wet-process photograph machines able to cover the larger gamut?  I understand that they should be able to print from any colour space, but there does appear to be a noticeable difference when I’ve sent sRGB files.  CMYK output isn’t an issue for us, as everything we do is either screen based (converted to sRGB) or printed on inkjet now and again.  Mostly it’s wet-process photographs.

Thanks for everyone’s expert input - this has been very interesting - I’ve learnt a lot!

Regards

Victoria
___________________________________________________________________________

   Date: Tue, 24 Feb 2004 07:52:51 -0700
   From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB

on 2/24/04 3:35 AM, Victoria Bampton wrote:

I understand which colours
are compressed/lost in sRGB vs AdobeRGB, and the benefits of not capturing
detail that can’t be printed/shown on screen, but considering our lab want
AdobeRGB and we’ve used AdobeRGB as our working space for the last 4 years
with no problems, what would be the benefits of capturing in sRGB, only to
later convert and therefore have to interpolate info?

None! Debate ended. Any color working space can be hosed if the user doesn1t understand how to handle the files. Dumbing down the process isn1t the right answer IMHO.

Dan, what makes you say that sRGB has become the industry default?

Dan usually has his ear on the 3industry2 and thus can tell us what is or isn1t a default. If the definitional of a default is one that1s not all that great that a lot of color clueless vendors are using as an excuse for good color practices (mostly consumer products in this case) then I guess it1s a default. Where I come from and based upon the PROFESSIONAL users I work with, Adobe RGB 1998 is far more a 3default2. That is, far more users that have a clue about color avoid sRGB expect for web use or purely display output.

UK, I haven’t yet come across a pro lab who don’t want AdobeRGB.

Then you guys are far more advanced then a lot of labs over here. Many have no idea about working in a color managed workflow, have un-calibrated displays and no output profiles for their devices. So the 3easy answer2 for customers who really don1t understand the process any more than the lab is to simply suggest files come in as sRGB. It might as well be monitor RGB (the users monitor ala Photoshop 4 and earlier).

Is this just a case of they don’t yet understand, or are wet-process photograph
machines able to cover the larger gamut?

There1s a nasty myth that such device can1t exceed sRGB (not true) or that no output devices can output a color space larger than sRGB (again not true).

I understand that they should be
able to print from any colour space, but there does appear to be a
noticeable difference when I’ve sent sRGB files.  CMYK output isn’t an issue
for us, as everything we do is either screen based (converted to sRGB) or
printed on inkjet now and again.  Mostly it’s wet-process photographs.

Even SWOP v2 (TR001) is slightly larger than sRGB.

Andrew Rodney
http://www.digitaldog.net
___________________________________________________________________________

   Date: Tue, 24 Feb 2004 23:08:03 -0500
   From:Russell Proulx
Subject: Re: Re: Adobe RGB vs. sRGB

On 24 Feb 2004 at 7:52, Andrew Rodney wrote:

There1s a nasty myth that such device can’t exceed sRGB (not true)

Andrew,

If it’s wrong then I really want to know what it right. Except for the few books available, such as those from Fraser/Murphy/Bunting book and Abhay Sharma, the main source of info on how ICC color management works are email lists like this one and websites such as

http://www.shootsmarter.com/infocenter/wc025.html

which offer up info on photo printers that appears to be well founded.

If the info on this website is wrong then I do wonder why don’t they know it? Where’s the motive to spread untruths?

I REALLY DO want colour management to work (at least in my RGB workflow) and find it disturbing to read so many contradictions and witness debates akin to Julia Child vs Jacques Pepin <g>

I’m sure I even read an old list posting (colorsync list?) where someone (no kidding, I really thought it was YOU) revealed that Fuji engineers specifically used the sRGB colourspace as their target for the color gamut characteristics of the Pictro.

I’m not looking for an argument (seriously). I only want to know what the right answer is. What I have noticed is that sRGB files sent unconverted (ie: processor doen not check for embedded profiles of incoming images) to Kodak/Noritzu minilab printers come out looking VERY close to what I see on the screen. Files in other colourspaces come out wrong.

Russell :-)

___________________________________________________________________________

   Date: Wed, 25 Feb 2004 00:51:44 EST
   From: Dan Margulis
Subject: Re: Re: Adobe RGB vs. sRGB

Victoria writes,

Dan, what makes you say that sRGB has become the industry default?  In the
UK, I haven’t yet come across a pro lab who don’t want AdobeRGB.

Adobe RGB has always been most popular among professional photographers. The question to which I was responding, however, pertained to “novices” and to Photoshop users as a whole. In that group, sRGB clearly has become the standard. In fact, posts to this group indicate that most professional labs in this hemisphere are looking for sRGB. Of course, this is all being driven by consumer-level digital cameras and printers, almost all of which operate in sRGB. Also, you’ve seen in this thread several suggestions from others that Adobe RGB carries disadvantages. Such commentary would have been unusual even two years ago.

A couple of months ago, in a significant milestone, several prominent members of the group that I call the Conventional Color Management Wisdom suggested that at this point, it is proper and desirable to assume that an RGB file without an embedded profile is an sRGB file. Previously, the CCMW had been that any untagged file is meaningless mystery meat.

In making this suggestion, the CCMW by no means is saying that sRGB is good, only that it has achieved a dominating position. If you decide to use some other RGB definition, fine, but you have to realize that you are living in an increasingly sRGB world, so the onus is on you to make sure that your non-sRGB files will be handled properly by others.

I don’t think novice users are capable of doing that, so I recommend that they stick with sRGB. In fact, I think all users should be looking at their workflow. There’s an advantage to working in a standard space, even if isn’t the standard space you yourself would want.  If you  look at your workflow and see a bigger advantage in working in some other RGB (as Russell does) fine. But if you can’t think of any reason to choose something different, I’d go with the flow at this point.

In your case, there does seem to be an advantage, and you don’t seem to have the risk of someone misunderstanding your file. Your lab wants Adobe RGB, and that’s what you should give them.

(Dan, how about doing a course in the UK?)

Find me a sponsor, and I’ll be happy to do it.  It seems kind of silly to me that I’ve given small-group classes in three different European countries, but never in my native language.

Dan Margulis
___________________________________________________________________________

   Date: Wed, 25 Feb 2004 03:01:15 -0500
   From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB

As the owner of a digital lab that is quite similar to the Frontier (an Agfa DLab which is also the Kodak lab you say you’ve used, Russell) I have some input here. I’ve profiled our lab, and it’s certainly not sRGB - it’s a little larger with a gamma closer to 1.8 than 2.5 and a warmer white point.

In our workflow, we prefer to have the client supply us with files that have embedded profiles so that we can properly convert them to the lab’s space. Neither sRGB nor AdobeRGB could produce correct results. This is in spite of the fact that the manufacturer says to use sRGB and many lab owners do. If you probe deeper, however, you’d discover that they say to use sRGB1.8 which isn’t even typically found on most systems (Dan, maybe it’s more common in Germany?).

Russell, the reason many portrait labs want sRGB files is that it’s quick and easy for them and the photographer. I tell my customers that the ‘s’ stands for ‘safe’. The color won’t be a perfect match to the display, it won’t be the optimal gamut for the printer, but there won’t be many surprises either. When you’re printing files by the pound for a low price, that’s all that matters.

The website you mention is full of half truths and misinformation. For example the concept that if the originating color space is larger than the destination’s then the out of gamut colors won’t print at all. This would be true of an absolute rendering (or a meatball sandwich) which is never done when converting to a smaller space. Then the claim that all the digital labs are sRGB, which they aren’t. Then, that the software doesn’t convert color spaces, some do, or that all labs want sRGB, I don’t and apparently neither do labs in the U.K.

There’s no motive for such misinformation, just one’s right to be wrong. They don’t know it because they’ve never seen better. If people think that a Whopper is a hamburger, then who am I to confuse them?

john castronovo
tech photo & imaging
___________________________________________________________________________

   Date: Wed, 25 Feb 2004 11:04:27 +0000
   From: Andrew Haley
Subject: Re: Re: Adobe RGB vs. sRGB

john c. writes:
 
The website you mention is full of half truths and
misinformation. For example the concept that if the originating
color space is larger than the destination’s then the out of gamut
colors won’t print at all.

The oddest thing about the site is that the redering of the colour space for Epson 2200 clearly shows that there is a substantial part of the printer’s gamut that is outside sRGB.  [*] However, because the volume of the printer colour space is smaller than sRGB, you might as well shoot in sRGB!  This seems like a total non sequitur.

Andrew.

[*] Actually, there’s more around the other side that they don’t show.
___________________________________________________________________________

   Date: Wed, 25 Feb 2004 10:00:18 -0500
   From:Russell Proulx
Subject: Re: Re: Adobe RGB vs. sRGB

On 25 Feb 2004 at 3:01, john c. wrote:

In our workflow, we prefer to have the client supply us with files that have
embedded profiles so that we can properly convert them to the lab’s space.
Neither sRGB nor AdobeRGB could produce correct results. This is in spite of
the fact that the manufacturer says to use sRGB and many lab owners do.

Thanks for the great info John! It does make a good argument for “when in doubt, send it in sRGB”. Obviously there’s a problem with mis-information that needs correcting.

Russell Proulx
Montreal
___________________________________________________________________________

   Date: Wed, 25 Feb 2004 09:11:14 -0600
   From: “Cliff White”
Subject: Re: Adobe RGB vs. sRGB

Dan wrote:

—-I just got back from an on-site where the images
were digital captures of flowers, and CMYK output was the only consideration.
That type of scenario screams out for something other than Adobe RGB.—-

Dan, what RGB space does it scream out for?  sRGB or something else?

We are a shop that shoots digital almost entirely for CMYK output (monthly magazine, some books, pamphlets, etc.)  Since switching to digital capture and boning up w/ Dan’s book and others we have started doing our own prepress prep of images.  We will very soon be getting our RIP installed to close the loop on that process.

I had been under the impression that, assuming we had total control of our files, it was better to shoot and work in a larger-gamut space in order to have more options and control when selecting what to clip when you convert to a smaller gamut space, be it CMYK, or another RGB.  Is this still a good assumption or is there something I’m missing?

CLIFF WHITE
Staff Photographer
Missouri Department of Conservation
(573)522-4115  ext. 3854
P.O. Box 180
Jefferson City, MO  65102
___________________________________________________________________________

   Date: Wed, 25 Feb 2004 07:32:05 -0700
   From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB

on 2/24/04 10:51 PM, Dan Margulis wrote:

A couple of months ago, in a significant milestone, several prominent members
of the group that I call the Conventional Color Management Wisdom suggested
that at this point, it is proper and desirable to assume that an RGB file
without an embedded profile is an sRGB file. Previously, the CCMW had been
that any untagged file is meaningless mystery meat.
 
I certainly wouldn1t agree with that in total. IF the file came untagged from a PC user, I1d first assume sRGB. If however the file came from a Mac user I1d suspect Apple or perhaps ColorMatch RGB. Anyone using untagged files on a Mac will find sRGB ugly (and vise versa on the PC with Apple RGB).

These files are still mystery meat and considering that there are no less than four matrix settings for sRGB in many digital cameras (including Adobe RGB), the file is still totally meaningless sets of numbers until a tag is provided that produces what the end user has to GUESS is the right color appearance.

I don’t think novice users are capable of doing that, so I recommend that
they stick with sRGB.

Which causes as many problems for Mac users working with sRGB in non ICC savvy aware applications. If the application is aware, then the file is tagged, previews correctly and this entire issue is moot.

In your case, there does seem to be an advantage, and you don’t seem to have
the risk of someone misunderstanding your file. Your lab wants Adobe RGB, and
that’s what you should give them.

True to a point but this will not allow the user to soft proof to the device and edit accordingly. Telling the lab yo