Printing without the use of a halftone screen pattern offers many advantages, although most processes utilized are impractical for long run commercial printing. Screenless lithography provides a practical means of making unscreened reproductions. While screenless lithography has been in use for many years, its working mechanisms have only recently been explained. Past studies have investigated many of the factors which contribute to the continuous tone effect of screenless printing, but none have scientifically 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 then 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 were shown to occur not only between areas of different density, but also within areas of uniform density. The different ink film thicknesses that exist on screenless lithographic plates affect their tone reproduction characteristics and contribute to their continuous tone capabilities.
Library of Congress Subject Headings
Printing plates; Lithography; Printing ink
Department, Program, or Center
School of Media Sciences (CIAS)
Summers, James Spruill, "Analysis of Ink Film Thickness on Screenless Lithographic Plates by Microscopy" (1982). Thesis. Rochester Institute of Technology. Accessed from
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