Patent ID: 8085436
Filing Date: 2011-12-27
Classification: H04N

Abstract:
1. A method for printing an input digital image having at least one color channel using a digital printer having a set of colorants, wherein two or more of the colorants in the set have substantially the same color but different densities, and printer code values for a corresponding color channel are used to control colorant amounts for the two or more colorants producing a corresponding color channel output response, comprising: (a) defining a sequence of node points where each of the two or more colorants are either at or near their maximum or minimum values, and where at least two colorants are at or near their maximum values for at least one of the nodes; (b) setting colorant concentrations for each of the two or more colorants such that the color channel output responses corresponding to the sequence of node points are substantially equally spaced in a visually uniform color space; (c) forming colorant control look-up tables for each of the two or more colorants, the colorant control look-up tables providing colorant control signals for controlling each of the two or more colorants as a function of the printer code value for the particular color channel, wherein the colorant control look-up tables define a nonlinear relationship between the printer code value for the particular color channel and the colorant control signals between the node points in order to provide smooth transitions in the color channel output response between the sequence of node points; (d) addressing the colorant control look-up tables with the printer code value for the particular color channel for each pixel of the digital image to determine the colorant control signals for each of the two or more colorants; and (e) controlling the digital printer using the colorant control signals for each of the two or more colorants to specify the colorant amounts for each of the two or more colorants producing a print of the input digital image.