Appraisal of Production Run Fluctuations from Color Measurements in the Image

Extensive measurements of representative samples drawn from both web and sheetfed illustration printing showed that certain colors are particularly prone to variations, among them dark gray and brown. During 19 production runs, the variations of these colors were followed in CIELAB color space and their deltaE distances from the production center were determined. They followed chi2 statistic, characterisable by a single parameter which could be linked to the standard deviations in L*, a* b* space. As a basis for quality appraisal, the distribution of the parameter over the sampled production runs is given.