Quite some time ago I wrote these remarks: Color Fidelity is Bullshit. It turns out there's another wrinkle. See this rather lame but nonetheless interesting piece. Or google up tetrachromacy and google around a bit.
A substantial percentage of women are not trichromats at all, but tetrachromats. We can also glean from this article that mutations that cause color perceptions to vary pretty widely are pretty common.
Ask a color management expert this question:
Suppose I have an apple. If I really work at it, and use the best gear and procedures to make a color accurate print of that apple, what percentage of the population will agree that the apple in the print is the same color as the actual apple?
Since this is precisely the biggest problem that color management is supposed to solve, you'd think they'd have some sort of answer. Andrew Rodney, one of the recognized experts, does not. Instead he has evasions, bullshit, and snark. Interesting, huh? If you do happen to get a straight answer to this question from someone, please report back here.
I know there is population variation, and I know there is precision in color management. I do not know how they relate to one another, and I would like to. How many decimal places of precision is it actually useful to squeeze out of your color managed workflow, given that there's variation in the population? 1? 2? 50? None?
The problem is that the answer to the question about the apple is, I assume, "well, not very many, and god help you if you change the illumination, it's not even going to be close, and as for those tetrachromats, well, ugh."
That answer, unfortunately, sells very few high gamut displays, colorimetry systems, books on color management, and so on.
Isn't there a contradiction here (or a paradox, or one of those things)? Surely, unless one's eye/brain combo yields variable results, "my" red will be consistently different from "your" red, so calibration will at least ensure that, if your end-to-end result from sensor to screen to print looks the same to you, then it will look the same to me, even if a consistently different "same"?
ReplyDeleteFor the same reason, I'm very suspicious of those wacky paintings on the site you refer to -- how on earth could she know that her subjective colour experience differs from the norm, much less represent it in paint?
Or am I missing the point?
Mike
Thing is the photo of the apple isn't the same color as the apple at all. The CMYK ink combination in play happens to produce a neural response similar to the original apple's color, but the spectrum is actually quite different.
DeleteThis means that if my eyes don't work the same as yours I might be fooled into thinking the colors are identical, i.e. that the photo matches the apple perfectly, and you might not be.
I'm a little suspicious of the paintings too. The neural processing of tetrachromacy is not understood, hasn't really been studied as far as I know, and probably makes much of the differences go away.
Anyways, to spoil color management all you need is for the peaks of those cute RGB curves for the eye's response to colored light to NOT fall in the same spot for everyone.
At this point I will just nod wisely, as if I had understood. It usually works for me.
DeleteMike
But you could in fact measure the spectrum of the apple and the spectrum of your print of the apple with sufficient color resolution and I assume if the spectra are the same then the perception by everyone should be the same. This should be a pretty easy experiment, I think I should try this out; it might be very entertaining.
DeleteYou could measure the spectrum of the apple and of the print, yes. And if they were the same people would indeed agree. In general you will find that the spectra are radically different and therein lies our difficulty.
DeleteSo we are trying this in the lab. If we make two prints (real apples are rare in the lab) with very close spectra they seem the same to most folk (although there are a few who see differences when there don't seem to be some) but we can make some prints that most people think are the same that are very different spectroscopically. Weird, not what I would have thought from first principles.
DeleteBut you need the real apple, otherwise you're just comparing fake colors. You'll probably still see differences, and its an interesting experiment. But it's a different one.
DeleteAll of which sometimes makes me yearn for the days of Kodachrome. Colour management? What colour management?
ReplyDeleteSounds like you may never have tried printing from transparencies (or colour negative), e.g. onto Cibachrome. Now that was a nightmare of colour control!
DeleteMike
Not a chance! I was perfectly happy to let others do that. First, because I'm lazy, and second, because I'm moderately colour blind. One of the small ironies of the digital age - colour-control beyond belief at my fingertips, and totally out of my reach. Ah, so sad. Orrrrr......not.
Delete