Patent ID: 6483607
Filing Date: 2002-11-19
Classification: G01J,G01N,H04N

Abstract:
A method for determining a set of np parameters that spectrally characterizes a colorant in order to predict the color of an overprint of the colorant with other colorants printed in an order of printing at a set of respective coverage percentages on a substrate of a substrate type using a printing technique, the method comprising:(a) making a selected number of sets of prints of the colorant on a selected number of respective substrates of the same substrate type, a set of prints including prints of the colorant on the respective substrate at a range of coverage percentages of interest, the selected number of prints at any particular coverage percentage being on backgrounds of said selected number of different background colors; (b) measuring the spectra of the prints of the selected number of sets of prints and the spectra of each of the different background colors; (c) if the selected number of sets of measured spectra is not sufficient to determine the set of np colorant parameters of the colorant as a function of wavelength and the coverage percentage of the particular colorant, overprinting one or more of the sets of prints of the colorant one or more times with at least one overprinting colorant, and measuring the spectra of each overprinting colorant and of the overprinted prints in the overprinted set of prints until a sufficient number of different measured spectra is obtained for determining the set of np colorant parameters; and (d) determining from the measured spectra the set of np colorant parameters of the colorant as a function of wavelength and the coverage percentage of the particular colorant.