Adobe perceptual and relative color mapping for LUT-based profiles

As I found out a month or so ago, Adobe RGB (matrix) color profiles map images among RGB color spaces by conversion and clipping in the object space. That is true for both perceptual and relative color intents. The intent checkbox is palliative, not functional. This is a disappointment. When going from larger- to smaller-gamut color spaces, there are times when you want to maintain detail near the gamut boundaries, and not having a real perceptual intent is limiting. What’s the situation for LUT-based color profiles, like those used for CMYK printers? The answer is that perceptual intent produces results that are for the most part different from relative color, and that the color mapping used is sometimes nonintuitive. Let’s put some meat on those bones. I built a MATLAB test framework around Bruce Lindbloom’s RGB16Million image, which contains a regular sampling of RGB color space. I interpreted that image as ProPhoto RGB, converted it through various CMYK printer profiles using…