Details:
Summary:
Screenless lithography is used in applications requiring reproductions superior to those obtained with halftone processes. While this process has been in use for many years, its working mechanisms have only recently been investigated. Past studies have investigated many of the factors which contribute to the continuous tone effect of screenless printing, but none have determined if ink film thickness variation is a contributing factor. Positive working lithographic plates were exposed to control scales, processed, inked, and allowed to dry. These plates were physically cross-sectioned and observed under a high magnification microscope to determine if variations in ink film thickness exist. Positive working lithographic plates were exposed to control scales, processed, inked, and allowed to dry. These plates were physically cross-sectioned and observed under a high magnification microscope to determine if variations in ink film thickness exist. Results showed that variations did indeed exist. These variations contribute to the ability of screenless lithography to reproduce continuous tone originals.