Digital image trapping system

摘要

A system for trapping of a dark image object on a lighter colored background is disclosed. In a system using a page description language including overprint operators, black image areas (such as text, lines, graphic objects and the like) can be set to overprint colored background areas in a manner that eliminates rendered image defects including page-colored "halo" effect that can occur when the cutout background area underlying the black object is misregistered with the black object that was intended to cover the cutout area. In other systems, the present invention may be employed as a disabling of the undercolor removal system of a colored area that would otherwise be present under the black object. Systems using black plus at least one other toners or ink color (such as cyan, magenta and/or yellow or many other colors) can usefully employ the system of the present invention. The trapping system of the present invention may also be employed on an object-oriented basis, such that different image object types are trapped according to the system of the present invention and at least one other trapping system.