Dot gain is the enlargement which takes place in a dot from the time the dot is captured or generated on the film until it is printed. Dot gain can cause many problems, including color variation and loss of contrast, and if uncontrolled is one of the main contributors to waste in offset lithography. Of the many factors influencing dot gain, inks have been found to be a major contributor. One property recommended for further investigation is ink viscosity, which is the resistance to flow of an ink. The purpose of this study was to investigate the effect of ink viscosity on dot gain in offset lithography. It was found that as ink viscosity increases, dot gain will decrease, and if ink viscosity is optimized, dot gain will be optimized. Experimentation was done on a single color, single impression sheet-fed lithographic press, with five inks of different viscosities. Results of this experiment show that ink viscosity is significant in affecting the amount of dot gain that occurs. Inks with 15 and 20 percent solvent added, which were less than 1000 poise viscosity, were found cause the significant difference. Other factors found to be significant were screen ruling and paper absorbency. The Yates Method of Analysis of Variance and graphing were used to analyze the data.
Library of Congress Subject Headings
Offset lithography; Printing ink
Department, Program, or Center
School of Print Media (CIAS)
Dailey, David, "A study of the effect of ink viscosity on dot gain in offset lithography" (1985). Thesis. Rochester Institute of Technology. Accessed from
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