This thesis describes a screening experiment designed to determine which of seven paper characteristics influence dot gain in web offset lithography. Dot gain is the enlargement of halftone dots during printing from plate to paper with a resultant increase in dot area. The variability of dot gain during a press run and from run to run is detrimental to the quality of black and white and color reproductions. The seven paper characteristics: gloss, smoothness, absorption, physical density, caliper, opacity, and formation are measurable characteristics used to describe the printability of a paper. Using one unit of a four-unit web offset perfecting press, four papers were printed and dot gain's two components, slur and fill-in, calculated. Correlation, regression analysis and graphic illustration were used to analyse data. The thesis concludes that smoothness is the main contributor to slur and absorption has the greatest influence on fill-in. Other paper characteristics shown to influence slur and fill-in are caliper and physical density. Also included are discussions of future experiments required to test the relationship between paper and dot gain and why certain paper properties may influence slur and fill-in.
Library of Congress Subject Headings
Offset printing; Paper--Printing properties
Department, Program, or Center
School of Media Sciences (CIAS)
Clark, Timothy, "A preliminary investigation into the effect of select paper characteristics on dot gain in web offset lithography" (1978). Thesis. Rochester Institute of Technology. Accessed from
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