Tuesday, February 13, 2007

Color fidelity as a goal: oxymoron → color integrity

In May 1996 I gave a controversial internal presentation at HP Labs with the title WWW + Structure =  Knowledge. It was sufficiently provocative that word spread in the Valley and I was asked to make an external version and give it in other venues, such as the PARC Forum. I finally decided to strip it down and make a conference paper, which is available here (subscription required); there are also a preprint and a copy of the slides.

Anyway, the conference at which I presented the paper was the Color Imaging conference at the 1997 Electronic Imaging Symposium, and the room was full of color scientists. The last bullet in the last slide was

Color fidelity as a goal: oxymoron → color integrity

What I explained was that when color printing happened in a closed system, it was relatively easy. When systems became open, things became more complicated, because now we had to deal with color management, device profiles, appearance modes, adaptation, remote proofing, etc.

Then, leaving the audience in shock, I claimed on the Internet color fidelity is an oxymoron, because users do not know about all those things and they do not want to know about them. Therefore, while there still is a traditional graphic arts market where color fidelity is a must, for publishing on the Internet color scientists have to come up with a different technology, namely color integrity.

While color fidelity entails color matching, color integrity means that a color palette must remain preserved in the sense that individual colors can change, but their relation must be preserved. I made the example of a page selling blue jeans, claiming that the color patches showing the available colors do not have to match the true colors, because people will not hold up their sweaters against the screen, which does not really mean anything. Instead, it the same vendor has also that sweater, then if the sweater matches the jeans, also their displayed images must match, regardless what the device calibration is. Also, if there are stone washed jeans, their color must be lighter than that of the original jeans and the black jeans must look darker.

A possible algorithm I sketched at the time was that under any conditions on any practical device, no color in the palette should move over a color name boundary, and if one takes the vector field of the error vectors, there should be no divergence. The latter condition meant that there should not be any “virtual” light source, so the human visual system can adapt to whatever the conditions are.

At the end of the session Lindsay MacDonald told me that I have to redeem myself and participate on a round table discussion with that title at the following Color Imaging Conference in Scottsdale. Never afraid to make a fool of myself in front of a big audience, I agreed.

Thursday, November 20, 1997 at 8:00 pm, the big conference room at the Radisson Resort in Scottsdale was full. The debate unfortunately was a little fragmented and raucous because the representative from Microsoft, maybe not used to Scottsdale’s hot sun, kept interrupting and blurting in the microphone “You guys do not worry about color, just use ICM and Microsoft Windows takes care of everything.”

Despite this annoyance I was able to make my point. At the beginning of the discussion panel moderator Jim King asked the audience to show by hand raining if they believe in color fidelity or in color integrity. Only a few hands rose for integrity, but all rose for fidelity. However, when at the end Jim asked again the question, the vote was 50/50.

Ten years have passed. I would like to know what people think about this today. Please open your heart and post you opinion as a comment. Let us reopen the discussion with the advantage of hindsight.