Four different types of grains of wipe-on lithographic plates (mechanical grains, a chemical grain and an electrolytic grain) were studied. The experiments were divided into two parts. The first part concerned surface characteristics of the grained plates, and the second one involved plate performance on a press. The grained plates' characteristics, including coarseness, gloss, directionality and depth of grain, were examined mechanically, optically and visually. The limitation of each method was discussed. The effects of the surface structures on coating thickness were reported. The experiments on the press were designed to find which grained plate produced the best printing qualities, such as printing sharpness and resolution. Their tone reproductions were reported graphically. Changes of wettability of the plates during the press run were investigated by contact angle measurements. The factors that caused the change of the contact angles were discussed. The wear of the images on the plates were tested under conditions of increased abrasion. Most of the data were analyzed by statistical techniques such as analysis of variance and multiple range tests. Under the experimental conditions, the printing sharpnesses and the tone reproductions of the test plates were alike. The chemically grained plates have higher resolution, compared to the anodized and the sandblasted plates. The chemical grained and the sandblast grained p1ates have better image adhesion than do the brush grained and the anodized plates, but their hydrophilic properties change faster than do the latter types.
Library of Congress Subject Headings
Lithography--Metal plate processes; Offset printing
Department, Program, or Center
School of Photographic Arts and Sciences (CIAS)
Pungrassamee, Porntawee, "Studies of the Characteristics of Different Grained Surfaces on Some Typical Lithographic Wipe-On Plates" (1975). Thesis. Rochester Institute of Technology. Accessed from
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