Instrumented Characterization of Lithographic Plate Surfaces and Half Tone Images.

Although surface profile traces can be utilized for the evaluation of etched lithographic the method is essentially qualitative. By applying computer analyses to digitized recordings, qualitative characterization of plate topography may be obtained. This approach has been applied predominantly in plate development studies, but is equally applicable to production quality control. In progressing plate development studies to actual printing, image analysis techniques have been applied to half tone images at the negative, plate and print stages, to study image quality as a function of plate topography. The techniques used are described and illustrated with samples and description of criteria employed to objectively categorize quality. In progressing plate development studies to actual printing, image analysis techniques have been applied to half tone images at the negative, plate and print stages, to study image quality as a function of plate topography. The techniques used are described and illustrated with samples and description of criteria employed to objectively categorize quality.