Compensation by Black (CB)

The aim of this paper is to examine the differences between UCR (Under Color Removal) and GCR (Gray Component Replacement) by testing these separation functions in three applications: Adobe Photoshop CS (an image editing application), Gretag Macbeth's Profile Maker 5.0 (profile maker), and Heidelberg's Print Open 4.0.5 (profile maker). Areview of the literature pertaining to the different types of separation was made and compiled. An Internet search was also made to check what a prepress employee would find out if he or she was to search for a definition of one of these types of separation.

The conclusions of the tests made suggest two alternative proposals and indicate a need to either:

1. Discard the term UCR and use only GCR, as it really only concerns gray component replacement. This would make it easier for people in the business to focus on the process itself instead of trying to understand the difference between the two types of separations, a difference which actually cannot be seen visualy in reality.
2. Discard both terms and introduce a new term CB (Compensation by Black). The software should give the user the possibility of choosing how much black will be used and where it will replace the use of a combination of the CMY process colors. In addition, a single term would make the user more aware of the problems of separation and of how separation will affect the print result.

The suggestions imply an extensive review of accepted terms and abbreviations within the graphic arts industry with the aim of giving them a uniform scientific meaning and definition. Thus, it is strongly recommended that the term, CB (Compensation by Black) should be implemented.