Automated color adjustment

Abstract

A method for determining (250) a change required in a selected base point in an input colorant space of a digital-image rendering system to obtain from the digital-image rendering system a desired reference output color to within a predetermined color tolerance comprises determining the required change based on a local approximation of the colorant/color relationship at the selected base point. Gradient points are automatically generated (210) that are proximate or coincident with the selected base point and that are different from any other base point than the selected base point. A linear approximation to the colorant/color relationship at the selected base point is computed (240) from the gradient points and the measured (230) output colors at the gradient points as rendered (220) by the digital-image rendering system and. The required change is determined from the local gradient of the colorant/color relationship at the selected base point.

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