Hirohiko Itoh


Improved print quality has been become an important issue for the flexographic printing method. This is especially true in the area of fine quality halftone reproduction. The nature of this printing method which uses elastic materials for its printing plate is difficult to control. The main issue is the control of the pressure between the plate and the substrate. Extensive research has been done to change the hardness and the structure of the plate, however, the pressure used to transfer ink still remains a critical factor in achieving good halftone quality. Although the critical pressure control of the impression from plate to substrate is accomplished mechnically by the press operator, the pressure between the plate and substrate appears to be physically uncontrolable. Equal pressure across the plate to the substrate can create a large quantity of dot gzin in the highlight area. This problem is caused by the relief height difference between the highlight and shadow areas. This paper suggests a solution to the problem of excessive dot gain in the highlight areas by the use of the duotone technique. A test was performed which compared a normal duotone technique using equal plate pressure for each plate and a experimental duotone technique for flexography which involves the use of a different amount of pressure for each printing plate. The tonal rendering characteristics were determined and compared for each duotone technique. The test results indicate that there was no improved image quality by the use of the experimental duotone technique described in this paper. Suggestions are included for further study on this subject to improve halftone quality by flexography.

Library of Congress Subject Headings


Publication Date


Document Type


Student Type


Degree Name

Print Media (MS)

Department, Program, or Center

School of Print Media (CIAS)


Charles Weigand

Advisor/Committee Member

Joseph Noga


RIT – Main Campus