Patent ID: 8634105

Claim:
A color printing method, comprising: receiving source color data represented in a first device dependent color space, the source color data representing at least one of a source vector graphic object type, a source text object type, and a source raster graphic object type; converting, by at least one image processing device, the source color data to intermediate color data represented in a device independent color space using a first multidimensional gamut mapping of the first device dependent color space to the device independent color space, the device independent color space having a neutral color component; converting, by the at least one image processing device, the intermediate color data to destination color data represented in a second device dependent color space using a second multidimensional gamut mapping of the device independent color space to the second device dependent color space, the second device dependent color space having only three primary color components and including a virtual black color component defined by substantially equal tonal values of each of the three primary color components, the second multidimensional gamut mapping including a mapping from the neutral color component of the device independent color space to the virtual black color component of the second device dependent color space; wherein for source color data corresponding to the virtual black color component, the method further comprises screening a first portion of the destination color data representing the source text object type into gray halftone data including a single bit corresponding to each of the three primary color components of the second device dependent color space and a single bit corresponding to the virtual black color component; screening a second portion of the destination color data excluding the first portion into color halftone data including a single bit corresponding to each of the three primary color components of the second device dependent color space and a single bit corresponding to the virtual black color component; rendering the gray halftone data into at least one pure black output pixel to be printed using a black colorant; and rendering the color halftone data into at least one process black output pixel to be printed using at least one non-black colorant.