HABIs in Color Proofing Systems

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. 

CROMACHECK , a totally dry overlay negative proofing system, introduced by DuPont in the 1980s, produces color overlay proofs instantly alter exposure by simply peeling off the cover film. CROMALIN , a product that is used to make surprints ( overprints that are deposited on a paper substrate) was introduced in the 1970s. 

Color overlays can be made quickly, but are only suitable for internal quality control because of grayed whites and highlight tints caused by internal reflection between films. 

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