Patent ID: 7728846

Claim:
A method for converting a three-color image data set comprising C1, C2, and C3 colors into a four-color image data set comprising C1, C2, C3 and W colors, the method comprising: dividing a color space comprising a C1, C2, C3, and W color point into a set of regions bounded by W and two of a group, said group comprising: C1, C2 and C3; and determining, in a processor, a mapping from image data points in any one of said regions, said image data points comprising C1, C2 and C3 color values, to image data points comprising C1, C2, C3, and W; and detecting, by a detector, image data points that are out-of-gamut; scaling only the out-of-gamut image data points to produce corresponding color image data points that are within gamut range, the scaling performed according to a scaling factor that is determined according to a ratio between the maximum allowed value and the maximum value of C1, C2, C3, and W.