ATD, appearance equivalence, and desktop publishing

Companion papers show why the CIE L*a*b* system of color coordinates is not optimal for use in desktop publishing (DTP) systems and how ATD remedies most of the problems of CIE L*a*b*. Since DTP deals primarily with the reproduction of images, DTP applications do not need to model human vision. They need only reproduce accurately in the image the reflective properties of the original. The eye does the rest. Linear arithmetic is adequate for this task. An intermediate color space decouples scanner calibration from printer control, leading to a system that is nearly device independent. Plots of Munsell and other color grids show the intermediate space to be uniform. The uniformity of the intermediate space and the linearity of the model lead to accurate gamut compression and negligible transformation errors using integer arithmetic operations on the 8-bit quantities associated with inexpensive DTP equipment. The resulting images are substantially better than those produced by current DTP programs.