Patent ID: 8164790

Claim:
A method of improving the print quality of an image printed on a receiver by a printer having a plurality of primary colors and one or more auxiliary colors, the method comprising: providing the printer having the primary and auxiliary colors; printing a set of color patches for each primary and auxiliary color using the printer; measuring the color and granularity of each color patch in the set; mapping the primary colors to each auxiliary color in turn, wherein the amount of each primary color in any mapping can be negative; selecting a respective valid replacement domain for each auxiliary color using the measured color and granularity values, so that in the valid replacement domain, a first selected amount of one or more of the primary colors is replaced by a second selected amount of the respective auxiliary color, and the granularity of the resulting combination of zero or more primary colors and the respective auxiliary color is below a selected allowable level; a curve-producing step of producing a respective set of replacement curves for each auxiliary color using the corresponding valid replacement domain, each replacement curve mapping an amount of one or more of the primary colors to amount of one of the auxiliary colors, each mapping being within the valid replacement domain, so that the color error between the primary colors without the auxiliary color and modified primary colors with the auxiliary color is below a selected threshold; receiving the image; and printing the image on the receiver with granularity below the selected allowable level using the produced replacement curves.