Abstract

The multi-angle screening configuration is by far the most widely used screening configuration for process color printing, but there are alternative screening configurations which may be preferable in certain situations. Color separations made using the Staggered Position One-Angle screening configuration are reported to provide printed reproductions on newsprint which appear sharper, offer improved color reproduction, produce smoother color reproduction, and preserve color better in the shadows. The staggered position technique can be generated with high-end scanners and prepress equipment, as well as with desktop publishing workstations using the "Flamenco" screening algorithm. However, the staggered position method may be subject to greater color variation than the multi-angle method due to random misregistration which can occur during a newspaper press run. This study investigated printed process color reproductions produced by the staggered position screening technique in comparison to reproductions produced by the multi-angle screening technique at two commonly used screen rulings, 85 and 100 lpi, on newsprint. During a press run, one printing plate at a time was laterally misregistered in eight increments. A total of 32 sample press sheets and an OK standard press sheet were taken during the press run. A series of printed color patches on each press sheet were measured with a computerized spectrophotometer to determine if the color difference (AE) between the sample and the OK standard press sheet was significant or not. The two screening methods were also evaluated for consistency of color reproduction. Using a two sample t-test, it was determined that color misregistration resulted in a significant statistical difference between the staggered position test target and the multi- angle test target for the same screen frequency. On an individual patch-by-patch comparison, there were certain patches which did not exhibit a significant statistical difference between the two screen configurations. It was also determined that the multiangle screening method produced consistent, acceptable color variation with every increment of misregistration. The staggered position technique produced unpredictable and often unacceptable amounts of color variation which varied with misregistration and the number of overprinting inks.

Library of Congress Subject Headings

Color printing; Photomechanical processes; Color separation; Screen process printing

Publication Date

2-1-1992

Document Type

Thesis

Department, Program, or Center

School of Print Media (CIAS)

Advisor

Noga, Joseph

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: TR977 .L37 1992

Campus

RIT – Main Campus

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