Patent ID: 8749861

Claim:
A method of reducing metamerism in a scanned document, comprising: scanning a characterization page using a plurality of filtered channels and an unfiltered channel to generate R, G, B, and W values; measuring the characterization page in colorimetric space to generate measured colorimetric values, wherein the measured colorimetric values are L*a*b* values; generating best fitting parameters of a conversion function from R, G, B and W values to colorimetric values, wherein generating the best fitting parameters comprises obtaining best-fitting parameters for a conversion to XYZ space; and employing the conversion function to convert scanned values from RGBW to XYZ values; and converting values from XYZ to predicted L*a*b* values, refining the best-fitting parameters, and minimizing a root-mean-square color distance (DE) between the predicted L*a*b* values and the measured L*a*b* values.