Why do images look different on different papers?

[John V.]

Could someone help me understand this?

If I have multiple papers profiled with the same device (colormunki) why is it the images don't always match? Example: an image on Epson Hot Press is much warmer than the same image on photo paper, which appears much cooler. Shouldn't these images match? Isn't that the point of creating paper profiles?

[digitaldog]

In two words: paper white (they differ, sometimes dramatically). There's also OBA's and the effect of the illuminant upon them which can produce 'issues'.

[John V.]

I don't mean to put you on the spot digitaldog, but I still don't understand. Shouldn't the profiles compensate for the paper white of different papers and produce colors that match?

[digitaldog]

I don't mean to put you on the spot digitaldog, but I still don't understand. Shouldn't the profiles compensate for the paper white of different papers and produce colors that match?

Profiles don't compensate or correct, they define (profile) a process. You don't even need a profile to see the vast differences in the paper whites, just look at two differing papers together within the same field of view. Take say a Matt paper with no OBA's then something like Epson Ultra Premium Glossy (who's paper white has a huge -7 bStar) and view them together.

[John V.]

I always thought creating profiles was to determine how a color "should" appear. For example when I print the colormunki charts, it's saying this is how your printer produces this red on this paper, and creating the profile defines how that red should appear, and defines what adjustments need to be made in order to achieve the "target" color. This is incorrect? Am I not looking at this the correct way? If I'm just totally off in my understanding, I apologize

[digitaldog]

"Red" is just an English word you and I use to describe a sensation deep in our brains. Computers have no such capabilities. They only understand sets of numbers to define a solid color patch and we use Lab which is based on how we see to produce those numbers. The profile is simply a descriptor of Lab values of single color patches and has no knowledge of images or color in context nor is it based on color appearance models. Colorimetry which is what you end up with after measuring a pile of colors is about color perception. It is not about color appearance. And Lab has flaws too.

[Tony Jay]

John, when one prints the colour "white" is the paper and nothing else.
If the paper is "cool" is has a slightly blue tinge then that is how the whites will look.
In fact all the lightest tones will also look cool.
The same principle applies to "warm" papers.

In addition, the texture of the paper also changes how a print looks and no ICC profile in the world can accommodate for that.

Discerning printers actually choose different papers, not only for the texture, but also based on the whether it is cool or warm for different images to specifically accentuate a look that is desired.

Tony Jay

[John V.]

I'm sure you all see what I'm saying, but since I'm not exactly happy with the way I worded my previous post, I'm jsut gonna throw this out there.

Suppose I have printed the colormunki targets on 2 different papers. I can understand why the colors do not match in their appearance. There is no form of color management in place whatsoever.

Suppose now I go through the process of creating profiles for both of these papers. I then go and reprint the targets, this time using the profiles I just created, with their respective papers, shouldn't I get two prints with colors that match each other?

Apparently not... What I'm gathering is that it's simply just the limitations of the technology... (?)

[John V.]

Come to think of it, that could be my real problem here. Or, at least part of it. I should experiment with viewing the 2 prints (mentioned in my original post) under different lighting conditions.

[digitaldog]

It's not noting to do with the limitation of technology, differing papers produce differing numbers and results due to the paper.
Make some print tests using Absolute Colorimetric where paper white is handled quite differently and tell us if you like the results (likely not).

[John V.]

hmm, that brings up another (perhaps related question). How/where is my colormunki getting the info to "simulate paper white" when soft-proofing. Is that gathered during the profiling process? I suppose it would have to be... I won't make a big deal out of this, just a point in the right direction perhaps. Thanks digitaldog, tony, and all.  

[digitaldog]

Is that gathered during the profiling process?

Yes.

[John V.]

lol

[Jimbo57]

Sorry Guys. I have to agree with John Drew.

The ICC profiles, whether supplied by the paper manufacturer or created by the ColorMunki, should allow the photographer to produce prints that match and which meet his requirements as specified to the printer by the image file he has produced.

Print the same image file on a variety of papers without dedicated profiles and, of course, the results will vary - not just because of base tints in the paper but because of myriad other factors such as reflectivity, ink absorption, and others.

But to say that "white" is simply the base paper cannot be true. If the paper is warmer than some, then the ICC profile should interpret "white" as requiring a slight blueish ink mix to be added and a "cold" paper may require whites to be warmed by the application of ink.

[digitaldog]

But to say that "white" is simply the base paper cannot be true.

OK, you can believe that if you wish. It is a bit like suggesting the illuminant is just "light" and assuming it has no role upon how we perceive the print.  
White, like Red is just a word, it tells us nothing about the color appearance of white.

The ICC profiles, whether supplied by the paper manufacturer or created by the ColorMunki, should allow the photographer to produce prints that match and which meet his requirements as specified to the printer by the image file he has produced.

ICC profiles know absolutely nothing about images. Or color in context.
IF you want to attempt to match two different prints, you have to cross render. And guess what happens? We use an Absolute Colorimetric intent which is IDENTICAL to RelCol expect how it maps paper white!

[Slobodan Blagojevic]

Count me in the perplexed category. Profiles are always paper specific, not just printer specific. If so, it would be logical to expect that, not matter what paper, the resulting image would look the same or very similar, as the profile would/should compensate for any differences. I understand that certain papers can not achieve the same maximum black, but color balance should be another thing. After all, the idea is to match print to screen, and screen is always the same.

[digitaldog]

Count me in the perplexed category.

Already assumed after our discussion of gamut and color numbers.  

Profiles are always paper specific, not just printer specific.

Both!

If so, it would be logical to expect that, not matter what paper, the resulting image would look the same or very similar, as the profile would/should compensate for any differences.

Logic based on misunderstandings of color management isn't sound logic.  

I understand that certain papers can not achieve the same maximum black, but color balance should be another thing. After all, the idea is to match print to screen, and screen is always the same.

Color balance is based on lots of items, one of them the white of the paper and your perception of that white. And yes, the idea IS to match print to screen and why, those of us serious about it use a reference display system that allows us to calibrate to multiple calibrations to do just that. We consider WP, contrast ratio when we do so, we end up with differing calibrations per paper due to that. Do you expect that if you send the same RGB numbers through a good profile to vastly different papers, those papers play no role? If not, how can you assume one target calibration for a display accounts for the differences? It can't.
It's funny to read people all over the web state: "I've calibrated my display and it doesn't match the print". When you ask them what they used for calibration aim points, they tell you someone suggested 120cd/m2 6500K (or D65 which isn't the same). Yes, they did calibrate the display, they just did it wrong! IF you calibrate your display correctly, you do so to produce a match and the settings will vary, one size doesn't fit all. How can it?

[Simon Garrett]

Count me in the perplexed category. Profiles are always paper specific, not just printer specific. If so, it would be logical to expect that, not matter what paper, the resulting image would look the same or very similar, as the profile would/should compensate for any differences. I understand that certain papers can not achieve the same maximum black, but color balance should be another thing.

Yes, within the capability of the paper and ink.  Remember that an icc profile is simply a measurement of the colour characteristics of the printer-paper combination.  With monitors, the monitor profiles usually also contain calibration information that is used to alter the characteristics of the monitor.  With printers, the profile is simply a measurement. 

Colours will look the same on two papers to the extent that the two papers and the ink are capable of displaying the same colours.  For whites this usually isn't so, as white is going to be the paper colour (i.e. with no ink on it), and two papers are normally different colours. 

After all, the idea is to match print to screen, and screen is always the same.

Screen matching is usually better, as when you run the profiling/calibration software on the monitor it calibrates as well as profiles.  That is, it adjusts the white (and tone response curve) to a standard setting such as D65 or whatever.  So whites will be right (so long as you've calibrated the monitor to the white that you want, of course).  Because one doesn't (normally) calibrate printers, you're stuck with the gamut and white point that the paper and ink combination can achieve. 

[Slobodan Blagojevic]

My understanding is that the OP is not just talking about empty (of color) areas in an image, where paper white would show through. My understanding is that he is talking about overall color balance.

[Slobodan Blagojevic]

... Color balance is based on lots of items, one of them the white of the paper and your perception of that white. And yes, the idea IS to match print to screen and why, those of us serious about it use a reference display system that allows us to calibrate to multiple calibrations to do just that. We consider WP, contrast ratio when we do so, we end up with differing calibrations per paper due to that. Do you expect that if you send the same RGB numbers through a good profile to vastly different papers, those papers play no role? If not, how can you assume one target calibration for a display accounts for the differences? It can't.
It's funny to read people all over the web state: "I've calibrated my display and it doesn't match the print". When you ask them what they used for calibration aim points, they tell you someone suggested 120cd/m2 6500K (or D65 which isn't the same). Yes, they did calibrate the display, they just did it wrong! IF you calibrate your display correctly, you do so to produce a match and the settings will vary, one size doesn't fit all. How can it?

Are you saying that you calibrate your monitor differently for different papers?