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DIGITAL TECHNIQUES FOR PRODUCING UNDER-COLORED HALFTONE IMAGES

IP.com Disclosure Number: IPCOM000025192D
Original Publication Date: 1983-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 65K

Publishing Venue

Xerox Disclosure Journal

Abstract

A technique is presented whereby halftone images can be processed easily and rapidly to produce the four separations required for the production of an under-colored image. Undercolored images have the advantage of reducing the cost of producing a colored image while at the same time increasing the image quality of the output colored image.

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XEROX DISCLOSURE JOURNAL

DIGITAL TECHNIQUES FOR PRODUCING UNDER-COLORED HALFTONE IMAGES Thomas M. Holladay

Proposed Classification
U.S. Cl. 430/54 Int. CI. G03g 13/00

A technique is presented whereby halftone images can be processed easily and rapidly to produce the four separations required for the production of an under- colored image. Undercolored images have the advantage of reducing the cost of producing a colored image while at the same time increasing the image quality of the output colored image.

When handling halftone images with a 16-bit computer, the halftone images corresponding to the red, green and blue exposures exist as 16 pixels/word (Le, 1 bit/pixel) for each of the three colors.

The undercolor black can be produced by AND gating the corresponding red, green and blue words together. The undercolor red, green and blue can be produced from a black image by AND gating an INOT of black (i.e., 0 --+ 1; 1 + 0) with the corresponding red, green or blue. Because these Boolean operations can be done by one computer at a time, 16 halftone pixels can be done simultaneously. Moreover, because the image is halftoned, the produced undercolored separations for the red, green, blue and black are exact. With four developers on a 6500 copier and a scanner, an undercolored image may be successively printed.

A colored copy may be obtained, for example, from a 6500 copier by producing four undercolor images on high contrast copy film, registering the four films in p...