Patent ID: 9347874
Filing Date: 2016-05-24
CPC Classification: G01N,H04N

Claim Text:
1. A method of operating a processing apparatus to determine a spectral measure of reflectance of an overprint of a plurality of inks made on a substrate using a printing process, the method comprising: (a) accepting in the processing apparatus a spectral measure of reflectance of a substrate at a plurality of wavelengths; (b) accepting in the processing apparatus a pre-defined order of printing an overprint of a plurality of inks on the substrate; (c) for each ink of the plurality of inks, for a respective amount of printing of the ink, accepting or determining in the processing apparatus a respective interaction of absorption and reflection function (“IAR function”) indicative of how the ink interacts with a layer of one or more other inks when printed over the layer of the one or more other inks; and (d) determining in the processing apparatus the spectral measure of reflectance of the overprint of the plurality of inks printed on the substrate in the pre-defined order in the respective amounts of the inks, including repeatedly multiplying, in the pre-defined order, for each additional ink added to a partial overprint of the inks before the additional ink is added, the spectral measure of the partial overprint by the exponentiation of: (i) the ratio of the spectral measure of the additional ink on the substrate to the spectral measure of the substrate, by (ii) the IAR function of the additional ink, starting with spectral measure of the substrate.