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Reproducing Reality

(September 2007) posted on Wed Sep 12, 2007

The challenge of color management.

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By Jake Widman

This is because a particular color can reflect (or emit) light at different wavelengths from many different points on the visible spectrum, not just those corresponding to the "right color." The eye responds to all those wavelengths but can only process them through the three color receptors (red, green, and blue), so different spectral profiles can produce the same color sensation.

Because of that, says Holland, "It’s not about ink any more. It’s about what the color looks like. ‘Appearance modeling’ of colors will become more and more important as the technology advances. Wouldn’t it be cool if you could proof what a textured wool skirt in a particular color would really look like?"

The new Windows Color System, for example, incorporates a "color-appearance model" that’s based on the CIECAM02’s set of equations to transform the tristimulus color space (used in color management today) in ways that take into account viewing conditions. (In CIECAM02, the "CIE" part is from the International Commission on Illumination, which is the international expert body on light and perception; CAM is for "color-appearance model," pointing to the idea that it’s supposed to account for the context in which the color is viewed. And 02 is the year of the current CIECAM model-before that there was CIECAM97.)

There are good economic reasons driving this process. For one, color varies not just by surface or lighting but, even more, by medium or material. Says Brown, "In cross-media production, people have to produce direct mail, packaging, a Web site, even something for a cell phone screen, for instance, and maintain a consistent brand across all of them. As long as companies have a desire to lock down their color, there will have to be a system for doing so."

Holland broadens the definition of "medium" even further: "Almost every industry has a need for professional color control." Standards exist for specifying and controlling paint and other colorants on the manufacturing side, he points out, but the design and printing side operate with a different set of standards. Given that, Holland asks, how, for instance, does Procter & Gamble make sure the color of the plastic bottle for liquid Tide matches the color of Tide in a cardboard box? X-Rite has technology on both sides, he says. "We’re converging them right now. It’s our responsibility to drive that."

In Frank Hueske’s view, "The best way would be to have spectral-color management." Spectral data measures the color itself across the entire spectrum, not just the tristimulus values based on the limits of human perception. And that would make it possible for spectral-color management to take into account lighting and surface conditions in a way that current color-management systems cannot.

"You would need spectral inks-inks for the entire spectrum, more than six or eight inks," says Hueske, "and you’d need a spectral CMM. I’m pretty sure that an entire spectral color-management system will arrive in 10 to 20 years. However, we’ll see a spectral CMM in the RIP within 2 or 3 years."

Derhak agrees with the goal, but is not quite so optimistic about the time frame. "A spectral-reproduction system is inherently difficult because rather than just three channels, you deal with maybe 31. The problem is that it’s a lot of work, and the overall benefit may not justify it," he warns. It would be worth it in the world of fine-art reproduction, he says, where they’re working with paintings with different surfaces and textures and spectral work is being done in museums. But beyond that, he wonders, "Are people going to be willing to pay for the extra cost to get spectral reproduction?"

That’s not to say his company isn’t preparing for a spectral future. "We do actually characterize printers using spectral data, and then we convert the spectral measurements to a colorimeter profile," he says. "But we still have the spectral data if we need it.

Regardless of how the next few years play out, the goal is still the same. "All our color technology is around two things: capture the reality in the first place, then emulate it or reproduce it effectively," says Holland. That is, and will continue to be, the bottom line.

Jake Widman is a freelance writer based in San Francisco. His last article for The Big Picture, "Garnering Better Shop-Floor Workflow" (July) examined how five shops re-arranged their equipment as well as staff to expedite the flow of jobs on their production floor.