Abstract: Compressed color image data are received, including a color table having first format data entries, each of which represents one of a number of different colors in a first data format, also including an index into the color table for each of several pixels. The first format data entries for the different colors are processed so as to obtain second format data entries, each of which represents one of the different colors in a second data format. A look-up table is then generated that includes the second format data entries for the different colors. A second format data value is then obtained for each of the pixels by using the index for the pixel to address the look-up table.

Abstract: Rapid processing of color print data so as to replace true black ink with process black ink, so as to minimize bleeding between colored regions of a printed document and black regions thereof. To replace black with process black in a raster line, multiple pixels are examined simultaneously in groups so as to determine whether the group contains at least one colored pixel, with the exact location of the colored pixel being obtained thereafter. The last color pixel in the raster line is obtained by inspecting each Nth subsequent pixel, thereby skipping N between inspections, until a first black pixel is encountered, and thereafter backtracking to obtain the first color pixel. Thereafter, all black pixels within a window marked by the first and last color pixels, plus a margin, are replaced with process black.

Abstract: A system for correcting pixel color values, with each color value represented by a byte of data, includes applying look-up table correction to first, second, third, and fourth bytes of input color value data to obtain corresponding first, second, third, and fourth bytes of corrected output data, simultaneously comparing the first byte of input color value data to a fifth byte of input color value data, the second byte of input color value data to a sixth byte of input color value data, the third byte of input color value data to a seventh byte of input color value data, and the fourth byte of input color value data to an eighth byte of input color value data.