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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

Another advantage to breaking out the Adobe CMM, says Adobe’s Constable, is that it supports processing of version 4 ICC color profiles. So does Vista’s WCS color management, but the ICM system in previous versions of Windows does not. So incorporating the Adobe CMM would enable the use of v.4 profiles in a non-Vista Windows workflow.

Derhak points to another intriguing trend affecting CMMs: "A move toward using dynamic, ‘smart’ CMMs." With a smart CMM, a profile can program the CMM to perform the transforms based on the optimum gamut mapping for the output device. Referring to the ICC, Derhak says, "We’ve added the ability for the profile itself to define a sequence of transforms. This will give more flexibility."

Sound great? The problem so far, Derhak warns, is that dynamic-color processing makes it hard to achieve consistency. It’s fine, he says, in a workflow with, say, one digital camera and one printer, but it’s not so great for a more elaborate workflow. Unless everyone is using the same version of the same CMM, two different profiles can trigger different results. Even if the CMMs are the same, two different computers can also give different results.

"The whole idea is to come up with a programmable CMM," says Derhak, "but we’re not necessarily there yet."

Devising, and dealing with, new color models

The final trend, and the one that will require the most work but offer the greatest promise of transforming the way we handle color, is geared toward a new, expanded way to define color. Today, ICC profiles and color management are based on the LAB color space, a theoretical model based on the way the eye perceives color without regard for viewing conditions. That makes it subject to metamerism, the situation in which two different colors can look the same, or two samples of the same color can look different, depending on how they’re viewed. A frequently cited example is the way the same color would look on a matte versus a glossy surface.