Patent ID: 7612915

Claim:
A computer-readable medium having instructions stored thereon such that execution of the instructions by a processing device causes a method for determining composite grays to be performed, the method comprising: defining target lightness values by performing a black point adjustment on lightness values of black device values, where performing the black point adjustment comprises evaluating: Lcrv=Lcbp +( Linp−Lpbp )*( Lwp−Lcbp )/( Lwp−Lpbp ), where Lcrv is a target lightness value being defined, Lcbp is a lightness value of a composite gray black point for a device, Linp is an input lightness value for a black device point, Lpbp is a lightness value of a process black point for the device, and Lwp is a lightness value of a media white point; defining target chromaticity values corresponding with a chromaticity curve of neutral grays; defining target black device values by performing gray component replacement on black device values, where performing the gray component replacement comprises evaluating: Kgcr=K max*(( Kinp−Kstr )/(UPPER− Kstr ))^ EF, where Kgcr is a linearized black device value being defined and having a replaced gray component, Kmax is an upper black device value for the device, Kinp is an input linearized black device value having a gray component to be replaced, Kstr is a starting value for gray component replacement, UPPER is an upper device value for the device, and EF is an exponential shaping factor; and determining composite gray device values by using the target lightness values, the target chromaticity values, and the target black device values.