Study of Objective Methods for Evaluating Sharpness in Lithography.

In the conventional method, sharpness is evaluated by examining press prints under moderate magnification. The precision of subjective methods such as this is poor, and the evaluations are tedious. In this paper, several methods for measuring and expressing sharpness are discussed. Each one was tested for precision and for correlation with visual results. From these experiments two test objects were found which can be used to evaluate both directional and non-directional effects influencing sharpness.