An Investigation of the Effects Screen Ruling and Dot Structure have on Dot Gain on Offset Newsprint

Dot gain is an inherent problem in printing on any substrate. Studies have been conducted in an effort to try to isolate the causes of the variables in the printing system to determine their influence on dot gain. The literature indicated some good reasons to suspect that course screen ruling would yield less dot gain than finer screen ruling. Investigations dealing with the effect that screen ruling has on dot gain have not yet been conducted. This study attempts to isolate the screen ruling which can yield the lowest amount of dot gain when printed on newsprint using square, round, and elliptical dot structures. It could benefit the newspaper industry to be able to control one of the many factors that influence dot gain. A total of twelve screens were chosen for this thesis; including four screen rulings (65,85,100 and 150) and three dot structures (round, square, and elliptical). Based upon the data collected and a statistical analysis of that data, it was determined that a course (65-line) screen ruling yielded less dot gain that a fine (150-line) screen ruling when printed on newsprint on the Goss Community Press. Furthermore, it was determined that any dot structure could be used and would yield satisfactory printed results