Color printing having a plural highlight color image map in a full color image

Abstract

Mapping of full color images to two-highlight color images which provides excellent results for both pictorial image and presentation graphics applications is described. Shades and tints for each hue in the original full color image are mapped to a corresponding triangle of colors in a tetrahedral of possible colors defined by the two highlight colors. The apex of the triangle of colors is varied within the tetrahedral of possible colors according to hue. Differentiations in the result colors for the fully saturated cases is provided while preserving the relative saturation and lightness behavior. The triangle of colors maps to a first triangle bordering one side of the tetrahedral, the first triangle corresponding to a first one of the highlight colors or a second triangle bordering another side of the tetrahedral, the second triangle corresponding to a second one of the highlight colors when the hue of the original colors matches one of the highlight hues. Mappings may be provided for printers using arbitrary highlight colors. The mappings preserve information important to the viewer without discarding dimensions of the color space. Different information can be preserved depending upon the particular application.

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