PATTERNING AND DOT GAIN IMPROVEMENT FOR VECTOR ERROR DIFFUSION

A method for processing color-image pixel-data for outputting by a multi-bit (N) color-image output device including the steps of (a) characterizing color-image pixels into N successive, associated scan lines of pixels, which lines are bridged, effectively for processing purposes, by successive N×N pixel groups distributed along the associated scan lines, and (b) for each such pixel group, applying processing to the pixels in the group, including vector error diffusion processing, in a pixel-by-pixel and scan-line-by-scan-line manner employing, cyclically, N different color palettes, one each for the different scan lines—one of which palettes is bi-tonal, and other(s) of which is (are) of a higher bit level up to the level N.