Patent ID: 7782490

Claim:
A method for generating a sensitivity matrix for color correction of a color marking device, the method comprising: determining what control operation a color marking device is being characterized for; selecting nominal CMYK values based on said determined control operation; determining color parameters for CMYK values based on said selected nominal CMYK values; and determining a plurality of different sensitivity matrices using said color parameters; and generating a sensitivity matrix using a chain rule of differentiation using said plurality of different sensitivity matrices as component matrices in said chain rule, said sensitivity matrix being defined as a gradient of Lab computed with respect to said CMYK values, wherein said determined color parameters comprise XYZ, R(λ), W, and cmyk, and wherein said sensitivity matrix, as given by ∇ CMYK Lab , comprises: ∇ CMYK Lab =∇ XYZ Lab ×∇ R(λ) XYZ ×∇ W R(λ) ×∇ W cmyk ×∇ CMYK cmyk , where component matrix ∇ XYZ Lab is a sensitivity matrix defined as the gradient of Lab computed with respect to XYZ, component matrix ∇ R(λ) XYZ is a sensitivity matrix defined as the gradient of XYZ computed with respect to R(λ), component matrix ∇ W R(λ) is a sensitivity matrix defined as the gradient of R(λ) computed with respect to W, component matrix ∇ W cmyk is a sensitivity matrix defined as the gradient of W computed with respect to cmyk, and component matrix ∇ CMYK cmyk is a sensitivity matrix defined as the gradient of cmyk computed with respect to said CMYK values.