Testing the Validity of Measuring Gray Balance with the GATF Color Circle, Grayness and Hue Error Values

The purpose of this study is to compare L*a*b* Grayness measurement accuracy with that achieved by a proposed new system which uses a re-purposed GATF Color Circle.

It is generally accepted that the visual or instrumental evaluation of gray balance targets is an effective method to control color balance for the four-color printing process. While the various gray balance measurement systems in existence use different instrumentation and quantify grayness in a variety of numeric and graphic formats their ultimate goal is identical. All gray balance measurement systems seek to measure and display grayness variations between a standard and a process grayness.

The results of the study show that both the L*a*b* system and the GATF Color Circle system are effective in quantifying and displaying differences between an actual and a desired grayness.