Color proofing

The right-reading positive image resides on the receptor film after lamination, exposure through a positive, and wash-out of the unexposed areas with a solvent or aqueous developer. The four-color proof is built up by the sequential lamination, exposure, and development steps. 

A high quahty version of a dye-sublimation printer has been developed specifically for color proofing. This device uses a laser writing head, rather than the typical thermal printhead, to produce higher resolution images. The device is capable of tme halftones, providing an accurate rendition of a printed page. It is, however, expensive both in equipment and materials cost. 

Bruno, M. H. Principles of Color Proofing, GAMA Communications, Salem, NH, 1986, 133-180. 

A major effort was undertaken in the late 1960s and early 1970s at Parlin under the leadership of Dr. A. B. Cohen to produce a series of photopolymer products. The office copy system, described earlier, failed to reach commercialization because electrophotography offered a better approach to this market. But there were three major areas that could be and were successfully entered color proofing, photoresists, and lithographic plates. 

Color proofs n. Prints, in color, either from the engraving or from the mounted plates. 

Adachi, Y. Shimizu, K. Masuda, T. Mochizuki, H. Image formation for color proofing using visible image-producing photosensitive material upon exposure. Jpn. Kokai Tokkyo Koho JP 05158226,1993 Chem. Abstr. 1994,121, 22569. 

Interest at that time was also devoted to photopolymerization, as a means to developing non-silver imaging systems. Here the driving force was application areas that were emerging, such as photoresists, color-proofing, lithographic plates, etc. Initially this involved dichro-mated colloids. 

This may be done with color overlay systems, which offer a quick assessment. These were the first color proofing systems—precolored films, which could be exposed to corresponding color separation films and developed in a solvent to give appropriately colored proofs. By superimposing four colored transparencies in register the printer could check color balance and other quality control parameters. 

The process of transforming a multicolor original into an accurate and pleasing color reproduction involves a series of complex manipulations conversion of continuous tones into halftones separation of multicolor images into individual films for the three primary colors and black and adjustment of color balance and composition. Prepress color proofing systems make it possible to check accuracy of these transformations without the high cost and time delay of on-press proofing. 

April 30,1986. Photopolymer positive surprint color proofing film based on epoxy acrylate monomer exhibits low dot gain, low time dependence of toning and good tonal range. Binder can be methyl-methacrylate/ethyl acrylate/acryhc acid copolymer, preferably crosslinked with zinc ions and plasticized with a second acrylate monomer and a mixture of triacetin and trimethylol propane. 

Paola (E. I. Du Pont de Nemours and Company). March 21, 1995. A process for preparing images, particularly color proof prints, in which tacky and non-tacky areas are produced by imagewise exposure of a radiation-sensitive layer is described. The tacky areas are toned with a toner having a tackiness that can be increased by irradiation with actinic radiation. Appl. August 10, 1993. 

Another problem was that the original HABI/DHP system had a light yellow background, which was unsatisfactory for color proofing applications. This was resolved by replacing the o-Cl-HABI or CDM-HABI by o-alkoxy-HABIs, e.g., the dimer of (2-o-ethoxyphenyl)-4,5-diphenylimidazole. 

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