Subjective Evaluation of Graininess in Lithographic Images.

Subjective evaluations of the graininess of a set of press sheets were made by a group of observers using the Pair-Comparison method. The object of this study was to determine a set of numerical response values which arranged the sheets in their correct order and spacing on a graininess scale. Good agreement was found between the various observers and also to objective granularity values derived from microdensitometer traces. The coefficient of correlation between graininess and granularity values was 0.97.