Dan Margulis Applied Color Theory

Exaggerated Blue in SWOP v.2

   Date: Wed, 17 Nov 2004 13:15:38 -0500
   From: Dan Margulis
Subject: Exaggerated blue with SWOP v.2

List members may recall that I mentioned several weeks ago correspondence with a reader who observed that a certain CMYK image in my book showed up on his monitor as being far bluer than it did in print. This led to a thread on the SWOP v.2 profile in Photoshop. The reader now has further questions which he has requested that I forward to the list for comment.

A reminder that the image has printed in so many different places with the same result that we can rule out the possibility of anything weird having happened at the printer.

Dan Margulis

***********************************
Subj: Re: Professional PhotoShop 6
Date: 11/17/2004 12:25:11 PM Eastern Standard Time
From: Andre Dumas
To: Dan Margulis

Dan, since your reply to my message was personal, I am not sure if the
following is in accordance with the Group’s etiquette?

A CD accompanying a book on Color Correction in Photoshop had an image which
when displayed on my monitor was *much* more bluish than the same image
printed in the book. ÊMy ViewSonic LCD monitor is calibrated with the
Eye-One Display calibrator.

I asked the author of the book:çIs it my monitor or is the image not
correctly printed in your book or is it the image on the CD that is not
right ?√ÊHis reply: √Most likely, the CMYK working space setting in
your system plus, possibly, your monitor calibration. Machine-generated
profiles are notoriously susceptible to overstating the purity of light
colors in CMYK. If you are using the SWOP v.2 Web profile as your CMYK
working space, that would be enough to cause the problem. On my own system
with my own profile, the screen matches the print, but loading the SWOP v.2
profile turns the screen very blue."

I am concerned about the statement "Machine-generated profiles are
notoriously susceptible to overstating the purity of light colors in CMYK",
if that is the case then it raises the following questions: Ê(a) What is the
point in using expensive electronic monitor calibrating equipment if we
cannot trust the results and Ê(b) What other method or procedure can we use
to insure that light colors in CMYK are not overstated ?

For the past couple of years I have been on the look-out for opinions on
Monitor Calibration here on the Colortheory group site and elsewhere on the
Internet and last month I finally purchased what is regarded as a quality
calibrator, now I am disappointed to learn that in spite of it all, ÊI still
cannot be reasonably sure that the colors on my monitor are the right
colors.

André Dumas

——- Original Message ——-
From: <Dan Margulis>
Sent: Monday, October 11, 2004 3:14 PM
Subject: Re: Professional PhotoShop 6

André,

The picture has appeared in five different U.S. book printings by three
different printers, in two different magazines, and in several different languages
printed in many different countries. Therefore, I have seen how it appears
more than ten different times with around ten different printing
companies. There .......

Amities,
Dan Margulis
___________________________________________________________________________

   Date: Wed, 17 Nov 2004 12:18:05 -0700
   From: Andrew Rodney
Subject: Re: Exaggerated blue with SWOP v.2

List members may recall that I mentioned several weeks ago correspondence with
a reader who observed that a certain CMYK image in my book showed up on his
monitor as being far bluer than it did in print.

Did the reader have an ICC profile that described the CMYK numbers of this image so he could assign this to the image? Did this image in CMYK have an embedded profile that allowed Photoshop to preview the numbers based upon how the numbers were output?


I asked the author of the book: << Is it my monitor or is the image not
correctly printed in your book or is it the image on the CD that is not
right ? ÊHis reply: << “Most likely, the CMYK working space setting in
your system plus, possibly, your monitor calibration. Machine-generated
profiles are notoriously susceptible to overstating the purity of light
colors in CMYK.

I1m not sure what he means by 3Machine generated profiles.2 As opposed to what, eyeball generated profiles? What machine? You can build an output profile using a flatbed scanner but it1s going to produce a pretty poor profile due to how that 3machine2 sees color. To say that Machine-generated profiles are notoriously susceptible to overstating the purity of light colors in CMYK without specifying the type of measuring instrument (if that1s what he means by 3machine) or the software that generated the profile from that 3machine2 is not factual.

If you are using the SWOP v.2 Web profile as your CMYK
working space, that would be enough to cause the problem.

Yes, IF the numbers in the CMYK file don1t reflect how the U.S. Web Coated (SWOP) v2 profile expects the output device to behave. That is, if you create CMYK numbers from a conversion that1s vastly different from U.S. Web Coated (SWOP) v2 of course there1s going to be a mismatch in the output and the soft proof. Photoshop only knows how to preview numbers based on what you tell it. If you tell it that a set of CMYK numbers is based on U.S. Web Coated (SWOP) v2 but in reality the CMYK number were based on something different, you1ve lied to Photoshop. Photoshop will lie back to you!

On my own system
with my own profile, the screen matches the print, but loading the SWOP v.2
profile turns the screen very blue.”

So there1s no problem right? Use that profile that produces the color appearance that matches. Assuming U.S. Web Coated (SWOP) v2 is the incorrect descriptor for the number instead of your own profile which does match makes sense. Do you know for a fact the original RGB data was converted using the U.S. Web Coated (SWOP) v2 profile and NOT the profile you say produces the right color appearance?

I am concerned about the statement “Machine-generated profiles are
notoriously susceptible to overstating the purity of light colors in CMYK”

Don1t be concerned until you are told what on earth he1s referring to.

if that is the case then it raises the following questions: Ê(a) What is the
point in using expensive electronic monitor calibrating equipment if we
cannot trust the results and Ê(b) What other method or procedure can we use
to insure that light colors in CMYK are not overstated ?

There are two primary piece in this puzzle that will produce consistent and correct color appearance from a pile of numbers. One is to have the display calibrated and more importantly profiled. If that1s not done, then there1s no telling what the numbers will produce on screen. The second piece of the puzzle is some descriptor of the numbers. You can make any CMYK image in Photoshop from any set of numbers (just use a solid color) and when you assign different profiles, you1ll see the color appearance change. The numbers have not! What1s going on here? Well Photoshop simply needs to know what say C15/M0/Y92/B0 looks like. It1s yellow but if you assign the U.S. Web Coated (SWOP) v2 profile and then the EuroCoated profile, you see the appearance change. Which one matches the output? Well if the numbers were sent to the device in which the profile used is currently describing the number, it will match (or we should say match vastly closer then picking the other profile).

The other factor that comes into play with good screen to print matching is if you have the Paper White/Ink Black setup in the soft proof, if you1re viewing the print under a 5000K box with a dimmer so display and box are producing the correct luminance, whether or not the ambient light in the room is ideal (having a pick wall with a big window shining light onto the area where the display sits isn1t a good idea). But the big factors are the display profile and the output profile and how they describe a big pile of numbers.  

For the past couple of years I have been on the look-out for opinions on
Monitor Calibration here on the Colortheory group site and elsewhere on the
Internet and last month I finally purchased what is regarded as a quality
calibrator, now I am disappointed to learn that in spite of it all, ÊI still
cannot be reasonably sure that the colors on my monitor are the right
colors.

Don1t be. But understand that the display is only one part of the puzzle. You can have the most expensive and accurate display on the planet and if you tell Photoshop a lie about the numbers, it will lie back at you. Again, you can see this by using the Proof Setup and picking various profiles while viewing the same numbers. The preserve color numbers check box is also very useful in showing you how one device would produce color from a set of numbers intended for a different device. The trick is in having the correct descriptors.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Wed, 17 Nov 2004 12:42:00 -0800
   From: jharmon
Subject: Re: Exaggerated blue with SWOP v.2

Andre Dumas wrote:

Machine-generated
profiles are notoriously susceptible to overstating the purity of light
colors in CMYK.

I would assume this person meant canned, standards-based profiles. But what they’re missing is that these profiles, such as SWOP v2, were created from actual presses and were not somehow artificially generated mathematically. Thomas Knoll characterized an existing physical press for the SWOP v.2 profile.

— Jeff Harmon
Colorhythm LLC
___________________________________________________________________________

   Date: Wed, 17 Nov 2004 22:00:04 -0500
   From: “jc castronovo”
Subject: Re: Exaggerated blue with SWOP v.2

I would assume this person meant canned, standards-based profiles. But what
they’re missing is that these profiles, such as SWOP v2, were created from
actual presses and were not somehow artificially generated mathematically.
Thomas Knoll characterized an existing physical press for the SWOP v.2
profile.

So what we need to know is if the file in question would print the way it looks on screen when viewed using the v2 profile, if the press it’s printed on matches the one that Knoll used to make the profile. I’m led to believe from the original post that for some reason it won’t.

john castronovo
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 01:04:05 -0700
   From: Chris Murphy
Subject: Re: Exaggerated blue with SWOP v.2

By default Photoshop is set to use U.S. Web Coated (SWOP) v2. That profile will take a neutral with an L* of 60 to 46C 38M 38Y 2K.

Using Photoshop’s Custom CMYK settings, also set to default converts L* 60 to 49C 38M 37Y 3K.

Indeed, the Custom CMYK separation itself is 3 points more cyan and one point more blue than the SWOP v2 version.

Saying the SWOP v2 profile is wrong and makes CMYK images look “too  blue” when the original file was clearly separated using some other  profile, most likely Custom CMYK defaults is just like saying Custom CMYK is wrong and makes CMYK images look “too yellow” when the original file was separated using SWOP v2 but viewing it with Custom CMYK defaults.

I have no doubt a ton of printers have press behavior that does a great job with Custom CMYK settings. But I also have witnessed SWOP v2 making good separations and soft proofs for actual press conditions when the press conforms to TR 001 behavior, which is what the SWOP v2 profile is based on.

Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 11:30:13 -0500
   From: Dan Margulis
Subject: Re: Exaggerated blue with SWOP v.2

Chris Murphy writes,

Indeed, the Custom CMYK separation itself is 3 points more cyan and one
point more blue than the SWOP v2 version.

You are measuring a neutral color. The actual picture Andre refers to has what might be referred to as pastel blues, and those are what he’s complaining about. The SWOP v2 profile puts more negative values (colder colors) in both the A and B channels on these colors than it should.

Here are some typical values in the area he complains about; I’m giving the LAB equivalents for SWOP v.2, for the settings I use for viewing, and for Photoshop 5 default settings:

35c18m1y=75L-4a-21b (SWOPv2); 80L-2a-17b (Dan); 78L0a-17b (PS5)

44c27m6y=68L-2a-21b (SWOPv2); 73L0a-18b (Dan); 70L+2a-18b (PS5)

53c26m10y=61L-1a-23b (SWOPv2); 66L+1a-21b (Dan); 63L+3a-20b (PS5)

60c42m30y2k=54L-3a-13b (SWOPv2); 59L-1a-13b (Dan); 55L-1a-11b (PS5)

Saying the SWOP v2 profile is wrong and makes CMYK images look “too
blue” when the original file was clearly separated using some other
profile, most likely Custom CMYK defaults is just like saying Custom
CMYK is wrong and makes CMYK images look “too yellow” when the original
file was separated using SWOP v2 but viewing it with Custom CMYK
defaults.

How the file was separated has nothing to do with it. Andre is looking at a CMYK file on his screen and he’s looking at a CMYK print. How the file made its way into CMYK is completely irrelevant because it’s there now and the question is whether Andre’s CMYK matches the printer’s CMYK.

I haven’t got access to Andre’s monitor and so can’t comment on what’s up there. But I have put that file on at least half a dozen client systems and viewed on their variously calibrated monitors, and I’ve seen at least 10 renditions of the file in print. When viewed through the SWOP v2 profile on any monitor, the appearance is cooler than in any printed piece, from which I deduce, Holmes-like, that the profile itself has a problem with this particular range of colors.

Dan Margulis
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 16:53:58 -0000
   From: “colorman042000”
Subject: Re: Exaggerated blue with SWOP v.2

Andrew Rodney wrote:

I1m not sure what he means by 3Machine generated profiles.2 As opposed to
what, eyeball generated profiles? What machine? You can build an output
profile using a flatbed scanner but it1s going to produce a pretty poor
profile due to how that 3machine2 sees color. To say that Machine-generated
profiles are notoriously susceptible to overstating the purity of light
colors in CMYK without specifying the type of measuring instrument (if
that1s what he means by 3machine) or the software that generated the profile
from that 3machine2 is not factual.

Thanks for your reply Andrew it helps to better understand how a  profile should be used, I wonder if Dan could give me more information about the phenomenon of “machine generated profiles being  susceptible to overstating the purity of light colors”, more  specifically I would like to know what I can do in order to avoid  this problem but still benefit from the use of a colorimeter.

Andre Dumas
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 12:08:51 -0700
   From: Andrew Rodney
Subject: Re: Exaggerated blue with SWOP v.2

Chris Murphy writes,

Saying the SWOP v2 profile is wrong and makes CMYK images look “too
blue” when the original file was clearly separated using some other
profile, most likely Custom CMYK defaults is just like saying Custom
CMYK is wrong and makes CMYK images look “too yellow” when the original
file was separated using SWOP v2 but viewing it with Custom CMYK
defaults.

on 11/18/04 9:30 AM, Dan Margulis wrote:

How the file was separated has nothing to do with it. Andre is looking at a
CMYK file on his screen and he’s looking at a CMYK print. How the file made
its way into CMYK is completely irrelevant because it’s there now and the
question is whether Andre’s CMYK matches the printer’s CMYK.

Of course it does! If the conversion wasn1t produced using the U.S. Web Coated (SWOP) v2 profile, assigning that profile or assuming that profile controls the preview.

I haven’t got access to Andre’s monitor and so can’t comment on what’s up
there. But I have put that file on at least half a dozen client systems and
viewed on their variously calibrated monitors, and I’ve seen at least 10
renditions of the file in print. When viewed through the SWOP v2 profile on
any monitor, the appearance is cooler than in any printed piece, from which I
deduce, Holmes-like, that the profile itself has a problem with this
particular range of colors.

Because the numbers in CMYK and the U.S. Web Coated (SWOP) v2 profile don1t belong with each other. This is basic Photoshop color theory.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 18:25:52 -0500
   From: Henry Davis
Subject: Re: Exaggerated blue with SWOP v.2

On Nov 18, 2004, at 2:08 PM, Andrew Rodney wrote:

 Because the numbers in CMYK and the U.S. Web Coated (SWOP) v2 profile don1t
 belong with each other. This is basic Photoshop color theory.

I’m sorry, that CMYK numbers don’t belong doesn’t sound like basic Photoshop color theory. This sounds like Adobe Photoshop SNAFU, maybe.  The combination of not providing profile editing and meaningless color numbers is not an indication of a clear development path.  If a monitor display has become the final arbiter for a file, then we are in a very un-precise arena.

Henry Davis
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 18:42:29 -0500
   From: Dan Margulis
Subject: Re: Exaggerated blue with SWOP v.2

Andre writes,

A CD accompanying a book on Color Correction in Photoshop had an image which
when displayed on my monitor was *much* more bluish than the same image
printed in the book. ÊMy ViewSonic LCD monitor is calibrated with the
Eye-One Display calibrator.

When you first sent me this information, and before receiving my response, there were four possible explanations. In order of most to least likely, they would be:

1) The image was printed incorrectly.
2) Your description of CMYK in your Photoshop Color Settings is wrong.
3) There is something wrong with your monitor calibration.
4) The publisher put a copy of the wrong image on the CD.

Your original message correctly identified three of the possibilities, missing only #2.

My response indicated that #1, although very likely if we know nothing more, was not possible because the image has been printed many times by many different printers with substantially the same result. Also, I said that #4 was extremely unlikely. Therefore, it is either #2 or #3, or possibly a combination. I don’t know what your CMYK setting is. However, if it is the SWOP v.2 setting, as I have explained in another post, it will preview the image as being too blue on any monitor.

I am concerned about the statement “Machine-generated profiles are
notoriously susceptible to overstating the purity of light colors in CMYK”.
if that is the case then it raises the following questions: Ê(a) What is the
point in using expensive electronic monitor calibrating equipment if we
cannot trust the results

The two have nothing to do with one another. We are speaking of a machine generated CMYK profile. When that profile is active and a CMYK image is open on your screen, the profile is used by Photoshop to convert the file to RGB internally and to feed the RGB data to your monitor. If the profile is wrong, then the RGB data that the monitor gets is wrong.

The monitor calibrating equipment seeks to insure that whatever RGB data is presented to the monitor will be accurately presented to you. However, it has nothing to do with converting the CMYK file into RGB data. If the RGB data it is getting from Photoshop is wrong, then the image you see will be wrong no matter how well your monitor is calibrated.

(b) What other method or procedure can we use to insure that light colors in CMYK are not overstated

We edit the CMYK profile or we use another one that works better, with an important caution.

There isn’t any perfect CMYK setting. Every one has strengths and weaknesses. If your CMYK setting is to blame for this particular preview problem, you have to bear in mind that it is a rather unusual image. If you start altering the setting in order to accommodate it, it is likely that it may adversely affect the preview of other images that are more commonly found.

Dan Margulis
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 17:25:51 -0700
   From: Andrew Rodney
Subject: Re: Exaggerated blue with SWOP v.2

on 11/18/04 4:25 PM, Henry wrote:

I’m sorry, that CMYK numbers don’t belong doesn’t sound like basic
Photoshop color theory.
This sounds like Adobe Photoshop SNAFU, maybe.

Not at all. You can send the wrong numbers to the wrong device. That1s not the fault of Photoshop.

Convert to SWOP uncoated and send those CMYK numbers to a Eruocoated press behavior. You think the color will be ideal? Nope.

The combination of notproviding profile editing and
meaningless color numbers is not an indication of a clear development
path.  If a monitor display has
become the final arbiter for a file, then we are in a very un-precise
arena.

All monitors operate in RGB. When you send CMYK data, a CMYK to RGB conversion to the screen has to take place. If the recipe for either the CMYK or RGB portion of this conversion is wrong, so is the soft proof. This has NOTHING to do with profiles. This was the case in Photoshop 2.5 and up.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 20:24:06 -0500
   From: Ric Cohn
Subject: Re: Exaggerated blue with SWOP v.2

If I understand Andrew correctly, he is so adamant that there isn’t (or is it can’t?) be any problems with the U.S Web Coated (SWOP) v2 profile, that I think there are some things I must not understand. I know from my (limited) personal profiling experience that I can build a profile that looks great with my basic sample image target, yet has some problem areas that show up with other images. My experience is that if I look carefully at the previous results I can see where this target didn’t show these particular tones or colors in sufficient detail to show the problem. If I then edit the profile to correct this area I can generally fix this problem without adversely affecting the previously good areas. I think this is much like software de-bugging where problems don’t show up until you have many users with different needs than originally tested for. Programs become better with bug updates— if the bug fixes are done properly the programs don’t get better in some ways and worse in new ways. Why wouldn’t we expect this for something so new as icc profile creation?

I have seen this same exaggerated blue myself. I took an image that I knew had large areas of blue-gray. If I take an untagged CMYK file (or discard the tag) and assign the SWOP v2 profile the pale blues are much brighter than with any Photoshop generated profile that I’ve looked at. I don’t have any images where I can look at 10 different printings, but it is bluer than my limited press experience. While Dan’s books probably aren’t true SWOP, I assume some of the repro is from magazines that try to print SWOP to satisfy their advertisers??  Are true experts like Andrew and Chris really saying that this profile can’t be “mostly good, but still in need of further refinement”?

BTW, I respect the experienced and passionate people on this list and hate to see flaming. I believe this is important stuff and actually kind of fun compared to most current events. Please, let’s all keep it civil.

Ric
___________________________________________________________________________

   Date: Thu, 18 Nov 2004 19:02:34 -0700
   From: Andrew Rodney
Subject: Re: Exaggerated blue with SWOP v.2

on 11/18/04 6:24 PM, Ric Cohn wrote:

If I understand Andrew correctly, he is so adamant that there isn’t (or
is it can’t?) be any problems with the U.S Web Coated (SWOP) v2
profile, that I think there are some things I must not understand.

There’s NOTHING repeat noting wrong with the profile. Ask Chris. We did a profile shoot out at Seybold a good 3 or 4 years ago testing several packages that build custom profiles as well as the U.S. Web Coated (SWOP) v2 profile to a device that did indeed behave as TR001 spec’s expect. The winner? U.S. Web Coated (SWOP) v2.

Send the wrong CMYK numbers to a device, it’s not going to fly. It’s as easy as that. This is very simple color theory!

The proof was in the proof (which I suspect Chris still has).

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 09:43:10 -0000
   From: Stephen Marsh
Subject: Re: Exaggerated blue with SWOP v.2

Andrew Rodney wrote:

Send the wrong CMYK numbers to a device, it’s not going to fly. It’s as easy
as that. This is very simple color theory!

I am in agreement with you Andrew.

Another simple concept is also what you and others have mentioned before in this thread, which I also agree with - assign/assume the wrong profile for a set of CMYK numbers and it’s not going to fly.

That is the case with the image in this thread. Why does the image appear too blue when assigned SWOP v2? Because it was not separated for the exact response that this profile dictates.

It is very simple.

I can’t understand the storm in the teacup.

Stephen Marsh.
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 08:52:25 -0500
   From: Terry Wyse
Subject: Re: Re: Exaggerated blue with SWOP v.2

On Nov 19, 2004, at 4:43 AM, Stephen Marsh wrote:

That is the case with the image in this thread. Why does the image
appear too blue when assigned SWOP v2? Because it was not separated
for the exact response that this profile dictates.

EXACTLY.

It is a fact, when you start looking at a variety of press profiles, particularly ones designed for commercial sheetfed printing, that SWOPv2 is anywhere from 2-5% too blue/cyan overall. When you look at the gray balance numbers it spits out, you’ll notice that the M+Y component is HIGHER than typical gray balance numbers, indicating that the profile is trying to compensate for “too much” cyan. Thus, if you separate an image using a profile that has more typical gray balance behavior (50c39m39y) and then ASSIGN SWOPv2 to this image (gray balance 50c42m42y), the monitor soft proof will look TOO BLUE overall. This occurs not only in neutrals but overall. The other thing I’ve noticed is that the cyan hue in SWOPv2 is more of greenish-cyan as opposed to the typical press inks that I’ve measured which use a more purple-ish cyan (more magenta contamination). The result is a more greenish-blue gray balance and secondary colors that are a bit off.

And of course, if you soft-proof using the same profile you separated with, you’d never see this, only when it goes to press and they’re using a slightly different ink set than what SWOPv2 was expecting. Anybody that separates their images using SWOPv2 but then sends the job to a commercial sheetfed printer is very likely to see this too-blue effect. These folks should consider separating their images using a profile derived from GRACoL TR004 data. The gray balance difference and ink hues between SWOPv2 (TR001?) and GRACoL TR004 are RADICALLY different! Why folks continue to use SWOPv2 for images that are destined for a commericial sheetfed printing is beyond me.

My 3 cents,
Terry
_____________________________
WyseConsul
Color Management Consulting

704.843.0858
http://www.colormanagementgroup.com
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 13:51:25 -0000
   From: “colorman042000”
Subject: Re: Exaggerated blue with SWOP v.2

—- In colortheory@yahoogroups.com, DMargulis@a... wrote:
 
The two have nothing to do with one another. We are speaking of a
machine generated CMYK profile. When that....

Sorry I thought you were talking about the profile generated with my colorimeter.
 
We edit the CMYK profile or we use another one that works better,
with an important caution.

I tried all my CMYK profiles, Japan Standard v2 is the only one that made the image match (+/-) the one in your book.

There isn’t any perfect CMYK setting. Every one has strengths and
weaknesses. If your CMYK setting is to blame for this particular
preview problem, you have to bear in mind that it is a rather unusual
image. If you start altering the setting in order to accommodate it,
it is likely that it may adversely affect the preview of other images
that are more commonly found.

Ok, but am I the only one who does not have the right recipe (profile) for opening this image correctly?  How am I to know which profile to use when opening an untagged CMYK image and if I find one that seems right how am I to know that it gives me the *correct* interpretation of that photo?

Andre Dumas
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 08:06:18 -0500
   From: Dan Margulis
Subject: Re: Re: Exaggerated blue with SWOP v.2

Stephen writes,

That is the case with the image in this thread. Why does the image appear too blue when assigned SWOP v2? Because it was not separated
for the exact response that this profile dictates.

No. You may be misunderstanding the scenario. As described by Andre, the method of separation is completely irrelevant. If the image appears too blue when assigned SWOP v2 it has nothing to do with the separation—it is that the *press* isn’t giving the response that the profile expects.

Andre has only a CMYK file plus a copy of the printed result. He also knows now that the printed result is not an aberration because many different printers who loosely conform to SWOP have gotten similar results. He does not know how the CMYK file was created; he does not have access to the RGB file from which it was created; and he does not know whether the printed result is what I originally expected it to be.  He only knows what happened when the ink hit the paper using the numbers in the CMYK file.

Under these circumstances, it makes no difference at all how the file was separated. It would only be relevant if Andre desired to know whether he was seeing on his monitor approximately what I was seeing on mine. That is not what he wished to know—he wished to know why what he saw something on his monitor that disagreed with what he saw in print. The probable answer is that his SWOP v2 profile did not agree with the actual print conditions.

I think the thing that’s causing confusion is that I pointed out that I in fact preview the image correctly because I don’t use that particular profile. This has nothing to do with Andre’s problem—he doesn’t know or care whether *I* have monitor-to-print agreement; he wants to know why *he* doesn’t.

For the record, I don’t know how the picture was separated because it has been appearing for several editions, but it couldn’t have been with the profile that I currently use to view it, which dates from 2001 (Andre’s book was printed in 2000), and it couldn’t have been prepared specifically for this printer, because the printer changes with every edition.

Dan Margulis
___________________________________________________________________________
 
   Date: Fri, 19 Nov 2004 08:34:37 -0700
   From: Andrew Rodney
Subject: Re: Re: Exaggerated blue with SWOP v.2

on 11/19/04 6:51 AM, colorman042000 wrote:

I tried all my CMYK profiles, Japan Standard v2 is the only one that
made the image match (+/-) the one in your book.

Then Assign that what was previously CMYK mystery meat.

Ok, but am I the only one who does not have the right recipe
(profile) for opening this image correctly?

No, when anyone sends you CMYK data with either the wrong embedded profile or no profile, Photoshop has been provided a big pile of CMYK numbers with no meaning and it makes a guess. In your case, the guess was just wrong.

 How am I to know which
profile to use when opening an untagged CMYK image and if I find one
that seems right how am I to know that it gives me the *correct*
interpretation of that photo?

You can only guess, then call up the bonehead that sent you the CMYK file and tell them to embed the profile used to convert the data FROM RGB. Otherwise you get to play the guessing game which only works IF you have the correct profile used (unlikely) or you have something reasonably close. Friends don1t give friends untagged documents IF the aim is to open and view and possibly edit the numbers. If you are provided a CMYK file and all you need to do is output the numbers, you don1t really need the embedded profile.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 08:57:29 -0600
   From: eric_bullock
Subject: Re: Exaggerated blue with SWOP v.2


What is the
point in using expensive electronic monitor calibrating equipment if we
cannot trust the results

If you had Dan’s profile you would be able to preview the image in Photoshop correctly, so this is not the fault of your calibration software/hardware.

Eric  Bullock
Color Guy
Hecht’s/Strawbridge’s Advertising
685 N. Glebe Road - 5th Floor
Arlington, VA 22203

703.247.2391
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 10:06:17 -0500
   From: Terry Wyse
Subject: Re: Re: Exaggerated blue with SWOP v.2

On Nov 19, 2004, at 8:06 AM, Dan Margulis wrote:

No. You may be misunderstanding the scenario. As described by Andre,
the method of separation is completely irrelevant. If the image
appears too blue when assigned SWOP v2 it has nothing to do with the
separation—it is that the *press* isn’t giving the response that the
profile expects.

You’re both saying essentially the same thing.

Tell Andre to 1) profile is monitor accurately and 2) start assigning various press profiles until the soft proof matches, or is at least close to, the printed results. Then he’ll be at least in the same ballpark as to how the image was separated.

Might I add that if the image had it’s original profile still embedded that none of this would’ve happened? (Sorry, I just HAD to say that!)
:-)

Cheers,
Terry
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 12:50:33 -0500
   From: Dan Margulis
Subject: Re: Re: Exaggerated blue with SWOP v.2

Terry Wyse writes,

Might I add that if the image had it’s original profile still embedded that none of this would’ve happened? (Sorry, I just HAD to say that!)  :-)

WHAT??? I should have provided the profile that I use when guessing at what an unknown, nominally SWOP-compliant printer will do, as opposed to letting people open with the profile that PHOTOSHOP uses when guessing at what an unknown, nominally SWOP-compliant printer will do??? Surely, you cannot possibly be suggesting that my best-guess profile is better than SWOP v2!!!!!!! You know perfectly well that I use Custom CMYK to make my profiles, and you have told this group that it’s completely lame and that quality results are impossible. Plus, I don’t even make machine measurements before I enter the ink values!

Terry!! SWOP v2 was made from certified measurements taken of certified pressruns!!! It was passed upon by THOMAS KNOLL!!! How can you possibly be suggesting that one of these hacked Custom CMYK profiles could be better???

Of course, Thomas may not realize that spectrophotometers are a little off when it comes to measuring light blues (Sorry, it just slipped out.)

Dan Margulis
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 12:53:58 -0500
   From: Dan Margulis
Subject: Re: Re: Exaggerated blue with SWOP v.2

Eric Bullock writes,

If you had Dan’s profile you would be able to preview the image in
Photoshop correctly, so this is not the fault of your calibration
software/hardware.

Only if you assume that I myself can preview the image in Photoshop correctly. At the time he asked his question, Andre could not assume this.

Dan Margulis
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 12:08:58 -0500
   From: Dan Margulis
Subject: Re: Re: Exaggerated blue with SWOP v.2

Terry Wyse writes,

It is a fact, when you start looking at a variety of press profiles,
particularly ones designed for commercial sheetfed printing, that
SWOPv2 is anywhere from 2-5% too blue/cyan overall.

Yes, and this image is absolutely tailor-made to highlight the problem, because its most critical areas are pastel blues.

Anybody that separates their images using SWOPv2 but then sends the job
to a commercial sheetfed printer is very likely to see this too-blue effect.

You have it backwards. If the separation is made using SWOP v2 the result will come out too gray in areas of light blue, which can be very, very bad. This is true of seps made for true SWOP conditions as well as for other press conditions.

Dan Margulis
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 12:31:54 -0500
   From: Dan Margulis
Subject: Re: Re: Exaggerated blue with SWOP v.2

Andre writes,

Ok, but am I the only one who does not have the right recipe
(profile) for opening this image correctly? ÊHow am I to know which
profile to use when opening an untagged CMYK image and if I find one
that seems right how am I to know that it gives me the *correct*
interpretation of that photo?

There *is* no right recipe for opening a CMYK file correctly. If you want to see a preview that is somewhat in the same ballpark as the printed result will be on those few hours of the few days in which the printing is being done approximately to professional standards, you have to take an educated guess as to what to put in. Sometimes you have specific knowledge of how things are with a particular printer, sometimes not. In this case, all you know is that the printing was done, presumably, by a printer who specializes in printing books and (from the copyright page) is located in the United States. Under those circumstances, the best preview from among the CMYK profiles that Photoshop provides is probably SWOP v2, just as you had it. However, you just have to know that there are certain images that won’t preview correctly, of which the one we are talking about is a particularly blatant example.

I realize that this is very hard for the beginning CMYK user, because it is nothing like the situation with RGB files. I am particularly sympathetic today, because I would never have guessed that some of the people who have been giving you advice could possibly be misunderstanding how CMYK works as badly as they are. Some of these people are among the leading experts in their field, but they are missing some of the fundamentals.

As you work more with CMYK files, it does get easier.

Dan Margulis
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 18:39:47 -0000
   From: “colorman042000”
Subject: Re: Exaggerated blue with SWOP v.2

Thanks Terry, I tried various profiles and found that Japan Standard V2 came somewhat close to making my monitor match the photo from Dan’s CD.  I have profiled my monitor twice to-day with the Eye-One colorimeter and am still getting the same results.

Could someone point me toward the archive discussing the pros and cons of embedding a profile in a CMYK image.

Andre Dumas
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 22:31:11 -0000
   From: Stephen Marsh
Subject: Re: Exaggerated blue with SWOP v.2

Andre Dumas writes:

Ok, but am I the only one who does not have the right recipe
(profile) for opening this image correctly? How am I to know which
profile to use when opening an untagged CMYK image and if I find one
that seems right how am I to know that it gives me the *correct*
interpretation of that photo?

What is your goal in opening the image and the use it will be put to?

It may not matter what profile is used, as you may be interested in the numbers. As in you have to reduce the total ink by 20% you could really care less how the image looks, as it is press concerns which you are making your edits around and not more creative visual edits.

If you wish to see how the CMYK values appear in a print/proofing condition which you know the profile actually describes (unlike this thread) – then use that profile, as you wish to predict final output rather than the authors intent. All you will do is output the files numbers, again the profile is meaningless when it comes to output concerns in an untagged numbers honoured over visual intent workflow.

If you wish to see how the author intended the untagged file to appear, then you do need to assign either the correct separation profile or to assign the profile that assumes the same/close conditions (unlike the image in this thread). You may then choose to convert from this assigned profile to the profile which better describes your conditions, if the above `numbers matter’ workflow fails to please (the numbers in the file not suiting the final conditions).

Stephen Marsh.
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 15:10:05 -0700
   From: “Les De Moss”
Subject: Re: Re: Exaggerated blue with SWOP v.2

From: <eric_bullock

If you had Dan’s profile you would be able to preview the image in
Photoshop correctly....

Conversely, if you had Dan’s skillful aura, you could will it to preview
correctly.

It’s Friday...
-Les De Moss
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 11:19:00 -0700
   From: Andrew Rodney
Subject: Re: Re: Exaggerated blue with SWOP v.2

on 11/19/04 10:50 AM, Dan Margulis wrote:

Terry!! SWOP v2 was made from certified measurements taken of certified
pressruns!!! It was passed upon by THOMAS KNOLL!!! How can you possibly be
suggesting that one of these hacked Custom CMYK profiles could be better???

It would be better of the printing condition was not confirming to TR001 (which is unfortunately often the case). IF the 900 odd patches of the press really did match the measured data that IS TR001, Thomas1s profile would be spot on. This was clearly illustrated in the Profile Shootout at Seybold mentioned in a former post. Chris Murphy has proven this empirically using a proofing device that WAS behaving as TR001 describes.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 12:06:36 -0700
   From: Andrew Rodney
Subject: Re: Re: Exaggerated blue with SWOP v.2

on 11/19/04 11:39 AM, colorman042000 wrote:

Could someone point me toward the archive discussing the pros and
cons of embedding a profile in a CMYK image.

Advantage: CMYK numbers have a meaning that allows Photoshop to preview those numbers (along with your display profile) correctly.

Should a CMYK to some other color space conversion be necessary, you can do this correctly because whenever you convert from color space to color space, the source (the meaning of the numbers) is as important as the destination (where you want the new values to go). Example, U.S. Web Coated (SWOP) v2 to Euroscale. You need BOTH profiles here to make the conversion. Note that CMYK to CMYK conversions can be tricky and this is where device link profiles are ideal. That1s another color theory discussion...

Using Proof setup, you can click on the Preserve Color Numbers and see via a soft proof what the file would look like if you simply sent the exiting numbers to the output device 3as is2. That is, what would U.S. Web Coated (SWOP) v2 look like if you sent those values to an output device (Euroscale) without conversion. Photoshop needs the embedded profile to show this to you. VERY useful. If the color appearance seems OK, no reason to convert. Or maybe you want to edit (pull what appears blue cast) by selectively color correcting the existing numbers based on the preview of how they would print to a different device.

Disadvantage: Embedded profile can take up to 1.5mb to 2mb of space PER IMAGE since the actual profile is inside each document. Strip out profile if you must or get a bigger drive.

Rips made in the 20th century might choke if it finds an embedded profile (find another service bureau).

IF you have a lot of documents and you don1t expect the person receiving the images to open, view or edit the files, you don1t need an embedded profile. The output numbers are correct for the device so the profile serves no purpose. It1s still a good idea to have it but it1s not necessary.

Last disadvantage is the people on the other end of the chain open the file, get a warning there1s a profile and their heads explode all over the monitor. These are usually the same people who run 20th century RIPs that chock on profiles and have the feelings that ICC profiles are evil. Find another service provider.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Fri, 19 Nov 2004 11:13:52 -0700
   From: Andrew Rodney
Subject: Re: Re: Exaggerated blue with SWOP v.2

on 11/19/04 10:31 AM, Dan Margulis wrote:

There *is* no right recipe for opening a CMYK file correctly.

Hogwash. The right recipe is the right recipe and defined by the ICC profile (or Sep condition) used. That and a calibrated display. Thousands of users do this daily.

If you want to see a preview that is somewhat in the same ballpark as the
printed result will be on those few hours of the few days in which the
printing is being done approximately to professional standards, you have to
take an educated guess as to what to put in.

Guess because someone didn1t embed the correct number description or just use the right descriptor. You1re making a case for the evils of CMYK mystery meat.

Sometimes you have specific knowledge of how things are with a particular
printer, sometimes not.

Obviously not having specific knowledge is not idea! Duh.

In this case, all you know is that the printing was done, presumably, by a
printer who specializes in printing books and (from the copyright page) is
located in the United States. Under those circumstances, the best preview from
among the CMYK profiles that Photoshop provides is probably SWOP v2, just as
you had it.

No, he told you the best preview that matched the printed piece wasn1t U.S. Web Coated (SWOP) v2 and using another descriptor was. So why are you making this so difficult for this poor user. We either KNOW the right answer or we1re guessing. Why are you telling him to guess something that clearly isn1t working for him?

However, you just have to know that there are certain images that won’t
preview correctly, of which the one we are talking about is a particularly
blatant example.

All images will preview incorrectly if the definition of the numbers are not correct.

I realize that this is very hard for the beginning CMYK user, because it is
nothing like the situation with RGB files.

It1s absolutely NO different with RGB! If you have RGB files that are untagged or using the wrong descriptor, the preview is wrong. As everyone else on the list has mentioned other than Dan, this is very simple color theory. Again, RGB and CMYK files are big piles of numbers and numbers don1t tell us what a color looks like alone. Take ANY set of RGB or CMYK numbers, assign different descriptors (using ICC profiles) and every preview will appear differently with NO change in the values.

I am particularly sympathetic today, because I would never have guessed that
some of the people who have been giving you advice could possibly be
misunderstanding how CMYK works as badly as they are. Some of these people are
among the leading experts in their field, but they are missing some of the
fundamentals.

The advice that makes no sense is yours in telling someone that a CMYK mystery meat file should or should not look and print a certain way when the people involved have no idea what the true meaning of the numbers are. Again, this is simple color theory.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Mon, 29 Nov 2004 17:18:19 -0700
   From: Chris Murphy
Subject: Re: Exaggerated blue with SWOP v.2

On Nov 18, 2004, at 4:25 PM, Henry wrote:

The combination of not providing profile editing and
meaningless color numbers is not an indication of a clear development
path.  If a monitor display has become the final arbiter for a file,
then we are in a very un-precise arena.

Yes, I agree with that assessment.
 
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
___________________________________________________________________________

   Date: Mon, 29 Nov 2004 17:15:15 -0700
   From: Chris Murphy
Subject: Re: Exaggerated blue with SWOP v.2
 
On Nov 18, 2004, at 9:30 AM, Dan Margulis wrote:

You are measuring a neutral color. The actual picture Andre refers to
has what might be referred to as pastel blues, and those are what he's
complaining about. The SWOP v2 profile puts more negative values
(colder colors) in both the A and B channels on these colors than it
should.

Dan, that profile is merely reporting back LAB values based on TR 001 behavior. You are effectively saying that TR 001 has more negative values in the A and B channel than it should.

The result of this is that separations using SWOP v2 have less cyan in them. About 10% less cyan on average.

How the file was separated has nothing to do with it. Andre is looking at a CMYK file on his screen and he's looking at a CMYK print. How the
file made its way into CMYK is completely irrelevant because it's
there now and the question is whether Andre's CMYK matches the
printer's CMYK.

Would you say the same thing if the file had been separated using a laser printer profile? Or was separated with an ink jet profile? Of course the separation matters. If he had separated with SWOP v2 the CMYK values would be different. They'd have less cyan and maybe a point or two more magenta. And then his file, when viewed with SWOP v2 assigned, would not look too blue. And when I've printed such separations to a press that conforms to TR 001 behavior, they are also not too blue.

I haven't got access to Andre's monitor and so can't comment on what's
up there. But I have put that file on at least half a dozen client
systems and viewed on their variously calibrated monitors, and I've
seen at least 10 renditions of the file in print. When viewed through
the SWOP v2 profile on any monitor, the appearance is cooler than in
any printed piece, from which I deduce, Holmes-like, that the profile
itself has a problem with this particular range of colors.

The profile's colorimetric table conforms to TR 001. If you want to argue TR 001 is wrong, that's a whole separate argument, but it's a road you're flirting with going down by saying the SWOP v2 profile itself has a problem.

I think there are two more likely explanations that in combination are causing this problem:

1. all printed pieces were printing with presses that did not have TR 001 behavior, therefore assigning SWOP v2 would be expected to result in displaying something other than what was printed.

2. SWOP v2 & TR 001 are printed on a yellow paper stock. Relative Colorimetric rendering, which is what the color sampler tool is based on, subtracts paper white from everything. Since paper white is yellow with SWOP v2, a relative colorimetric rendering is going to have a lot less yellow in it (i.e. it will appear blue). This adaptation doesn't occur with the built-in engine as it flat out ignores paper white as a factor.

It is also possible that the algorithms responsible for producing relative colorimetric data from the colorimetric tag in the profile is overcompensating for paper white. Regardless, these issues are not problems with the profile itself.
 
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
___________________________________________________________________________

   Date: Mon, 29 Nov 2004 17:32:32 -0700
   From: Chris Murphy
Subject: Re: Exaggerated blue with SWOP v.2

On Nov 18, 2004, at 7:02 PM, Andrew Rodney wrote:

There's NOTHING repeat noting wrong with the profile. Ask Chris. We did a
profile shoot out at Seybold a good 3 or 4 years ago testing several
packages that build custom profiles as well as the U.S. Web Coated (SWOP) v2
profile to a device that did indeed behave as TR001 spec's expect. The
winner? U.S. Web Coated (SWOP) v2.

No. It was U.S. Sheetfed Coated v2 which is based on a Matchprint proof of some sort.

But I can say that U.S. Web Coated (SWOP) v2 has a B2A tag (CMYK to LAB) that adheres to TR 001 behavior. So that part of the profile isn't the problem.

Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
___________________________________________________________________________

   Date: Mon, 29 Nov 2004 17:29:39 -0700
   From: Chris Murphy
Subject: Re: Exaggerated blue with SWOP v.2

On Nov 18, 2004, at 6:24 PM, Ric Cohn wrote:

Are true experts
like Andrew and Chris really saying that this profile can't be "mostly
good, but still in need of further refinement"?

I'm not saying that. But I would say that the architecture is the bigger problem, in my opinion, than the profile. In the current context, we are talking about the portion of the profile that takes CMYK values and turns them into LAB. That table is pretty much dead nuts on compared to TR 001, an actual press run conforming to SWOP. Therefore I doubt the problem is in that portion of the profile.

I think it is very likely that all 10 printing conditions do not conform to TR 001. It is also possible that the CMS is overestimating how much yellow to pull out of previews, which by default use Relative Colorimetric rendering. Relative Colorimetric is not built into profiles, it's produced on the fly through an algorithm that takes the Colorimetric table (which is what is used with the Absolute Colorimetric rendering intent) and essentially subtracts the white point. There are problems with this, namely that a paper white of L*90 suddenly is assumed to be an L* of 100 which causes separations to be too dark. This may also be causing separations to come out a little too blue but that's why we're really supposed to be using paper white simulation on-screen.

That this doesn't occur with Custom CMYK probably has to do with the CMS ignoring the paper white entry with Custom CMYK generated profiles.

Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
___________________________________________________________________________

   Date: Tue, 30 Nov 2004 09:53:21 -0800
   From: Lee Varis
Subject: Re: Exaggerated blue with SWOP v.2

On Nov 29, 2004, at 4:29 PM, Chris Murphy wrote:

...There are problems with this, namely that a paper white of L*90
suddenly is assumed to be an L* of 100 which causes separations to be
too dark. This may also be causing separations to come out a little too
blue but that's why we're really supposed to be using paper white
simulation on-screen.

I think this is exactly right and the screen rendering from CMYK (via LAB) is the biggest problem with the user's interpretation of CMYK on screen.

Paper white simulation on screen is kind of a kludge... I can't get anybody to use it because it just "looks" bad! Mostly its because we're just so adapted to the general white point of the OS on screen that the "paper white" simulation makes everything look dingy. I've been forcing myself to use "Paper white" whenever I work in CMYK for a while now and, though it takes some serious getting used to, I've found that it really helps to predict press behavior visually! The problem is that you really have to adapt to an unnatural viewing experience and understand what you're looking at. The other thing you have to realize is that the screen image CAN NOT be directly compared to a physical proof – you can't place the viewing box next to the screen and expect the two images to look exactly the same (even with adjustable brightness viewing boxes)!

What paper white simulation does do however, is force you to get adequate contrast into your image and adjust subtle colors to the effects of "normal" white printing paper. It also helps in visualizing darkness differences due to adjustments of K vs CMY in black. This "soft proofing" is not easy to get used to and I think it requires too much mental/imagination calibration for most users. In fact, it only works when you have an adequate understanding of CMYK "numbers" that you can apply to what you're experiencing on screen.

All that being said, I won't work any other way than to use "Proof Colors" with "Simulate Paper White"

regards,

Lee Varis
http://www.varis.com
888-964-0024
___________________________________________________________________________

   Date: Tue, 30 Nov 2004 11:56:59 -0700
   From: Andrew Rodney
Subject: Re: Exaggerated blue with SWOP v.2

On 11/30/04 10:53 AM, "Lee Varis"  wrote:

Paper white simulation on screen is kind of a kludge... I can't get
anybody to use it because it just "looks" bad! Mostly its because we're
just so adapted to the general white point of the OS on screen that the
"paper white" simulation makes everything look dingy.

Exactly! It looks bad for two reasons, both of which can be overcome. One is you simply can't watch the update from RelCol to Absolute display rendering. It screws with your head. Put your cursor over the option, look away and click (or make a custom setting and make an action and of course look away). After a few seconds of ignoring the before then after, it doesn't look so bad.

The other issue is the white of the GUI elements which do not undergo the white simulation. You simply have to view the preview in full screen mode with all palettes and menu's disabled. If you look at the white of those elements, the white adaptation of your eyes makes the white in the image again screw with your head. This doesn't' make editing while in this mode very easy! So I usually set this mode when showing clients a soft proof (always show them the worst possible but accurate preview) or when viewing the screen and print together.

Be cool if Adobe could somehow make the palettes and menu's alter their white but I suspect the OS will not allow it.

Andrew Rodney
http://digitaldog.net/
___________________________________________________________________________

   Date: Tue, 30 Nov 2004 12:12:50 -0700
   From: Chris Murphy
Subject: Re: Exaggerated blue with SWOP v.2

On Nov 30, 2004, at 10:53 AM, Lee Varis wrote:

Paper white simulation on screen is kind of a kludge... I can't get
anybody to use it because it just "looks" bad! Mostly its because we're
just so adapted to the general white point of the OS on screen that the
"paper white" simulation makes everything look dingy. I've been forcing
myself to use "Paper white" whenever I work in CMYK for a while now
and, though it takes some serious getting used to, I've found that it
really helps to predict press behavior visually! The problem is that
you really have to adapt to an unnatural viewing experience and
understand what you're looking at. The other thing you have to realize
is that the screen image CAN NOT be directly compared to a physical
proof – you can't place the viewing box next to the screen and expect
the two images to look exactly the same (even with adjustable
brightness viewing boxes)!

Yes exactly. There's also the question of the surrounding user interface, including the totally neutral gray surround which does *NOT* have the simulation applied to it. This is less of a problem than white user interface elements, which can inhibit chromatic adaptation in the human visual system, and make the white simulated document look all the more dingy and yellow. Yes it is dingy and yellow, but we really need to allow our eyeballs to do what they were designed, and any interference prevents this from being as effective as possible.

There's also the small lack of appearance  modeling which is what we'd need to compensate for difference in illumination of the print and luminance of the display. This can cause a bigger problem than discrepancies in white point.

What paper white simulation does do however, is force you to get
adequate contrast into your image and adjust subtle colors to the
effects of "normal" white printing paper. It also helps in visualizing
darkness differences due to adjustments of K vs CMY in black. This
"soft proofing" is not easy to get used to and I think it requires too
much mental/imag