Patent ID: 7136189

Claim:
In a color output system, a method of rendering a color document with a multi-level halftone process using a single screen for a plurality of color separations wherein the screen is comprised of a plurality of pixel locations associated with successive threshold values, the method comprising rendering at least one of the color separations at a pixel location with a selected output value from allowed output levels, said selected output value being determined by an input color value for the separation at the pixel location, a maximum output value allowed, the halftone screen, and input color values of previously processed separations; and wherein the rendering of a successively processed separation outputs a requested color amount in a non black area using a plurality of output levels comprising a darker and a lighter output levels and wherein, the darker output level occupies lowest available threshold values of the screen at a highest luminance in the non black area, and the lighter output level occupies other available threshold values of the screen in the non black area adjacent to the darker output level.