Patent ID: 7375849

Claim:
A method of gray balancing comprising: printing a plurality of color samples that encompass predetermined gray targets, wherein the plurality of color samples are printed pursuant to a plurality of combinations of CMY values; measuring the color of the color samples in a predetermined color space to produce colorimetric data for the color samples; interpolating the CMY values of the color samples using the colorimetric data to determine discrete CMY combinations that substantially match the predetermined gray targets; performing a curve fitting procedure on the discrete CMY combinations to produce gray balancing curves; and modifying CMY data values for a pixel in accordance with the gray balancing curves, wherein modifying CMY data values comprises: determining a gray component of the CMY data values using: GRAY=MIN( C, M, Y ) wherein MIN(C, M, Y) is a minimum of C, M and Y; and modifying each of the CMY data values using: C=C +(GRAYBAL — C ( C )− C )*RATIO M=M +(GRAYBAL — M ( M )− M )*RATIO Y=Y +(GRAYBAL — Y ( Y )− Y )*RATIO wherein GRAYBAL_C(C), GRAYBAL_M(M), and GRAYBAL_Y(Y) are gray balancing curves, and RATIO is the ratio between GRAY and a maximum of the original values of C, M and Y.