US 5,613,046 A · Method and apparatus for correcting for plate misregistration in color printing

Abstract

A method and apparatus for compensation for misregistration of printing plates in printing of polychromatic document pages or images, in which a trapping map image is superiraposed upon a structured graphic image representing the layout of a document page or image from which it is derived, so as to prevent light leaks and other errors at the boundaries between color regions within the image. The trapping map image is itself a structured graphic object to be included as the last object imaged in the data representing the original image. The geometrical description of this trapping map image is independent of specific trapping decisions applicable to the associated image. Instead, such decisions are controlled by means of a user interface providing options ranging from fully automatic to completely manual interactive operation.

Claims34

Dependent claims

A method for generating a TRAPPED GRAPHIC IMAGE from an STRUCTURED GRAPHIC IMAGE comprising the following steps:

(A) generating a BOUNDARY MAP from the data representing said STRUCTURED GRAPHIC IMAGE, said BOUNDARY MAP containing a plurality of line segments and being unaffected by any trapping decisions, separation or rendering decisions made after the BOUNDARY MAP is generated;
(B) generating a TRAPPING MAP by defining stroke characteristics for some or all of the line segments making up said BOUNDARY MAP;
and,
(c) combining said TRAPPING MAP with said data representing said STRUCTURED GRAPHIC IMAGE such as to cause said TRAPPING MAP to be superimposed upon said STRUCTURED GRAPHIC IMAGE when rendered for output processing.

1 more element

An apparatus for interactive display and modification of trapping infomation for a STRUCTURED GRAPHIC IMAGE comprising:

(A) means for display of said STRUCTURED GRAPHIC IMAGE, the results of any candidate trapping operation and conditions previously established;
(B) means for selecting elements of displayed data for analysis and and/or modification;
(C) means for displaying all possible colors resulting from printing plate misregistration for said selected elements and said previously established conditions, without applying any trapping operation;
(D) means for displaying all possible colors resulting from printing plate misregistration for said selected elements and said previously established conditions as a result of a candidate trapping operation;
and,
(E) means for applying trapping operations to said selected elements.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for correcting for plate misregistration in color printing

Life of this patent

Method and apparatus for correcting for plate misregistration in color printing

Life of this patent

Abstract

Claims34