A study of the effects of clear extender varnish modification of gravure inks to produce an allowable color tolerance between a halftone gravure print and a SWOP standard offset press proof in hue, saturation, and brightness
Halftone gravure has become the accepted front end imaging procedure for the publication gravure industry. Halftone gravure refers to using screened or halftone film when imaging a gravure cylinder. This procedure has allowed the publication gravure industry to benefit from the prepress advantages of offset printing. Therefore, the possibilities of an allowable color tolerance between a halftone gravure print and a SWOP standard offset press proof in hue, saturation, and brightness needed to be studied. The purpose of this study was to determine whether an allowable color tolerance could be achieved between the gravure production print and the SWOP standard offset press proof. The experimental design involved the research of the effects of clear extender varnish modifications of gravure inks used to produce an allowable color tolerance between a gravure print and a SWOP standard offset press proof. It was important to compare the gravure print to the SWOP standard offset press proof because the publication gravure industry recognized the SWOP standard offset press proof as the standard or control parameter. The methodology was based upon the modification of gravure inks by the addition of 10% intervals of clear extender varnish. Five intervals of 10% clear extender varnish were added to each of the gravure inks. After the gravure prints (10% to 50% clear extender varnish added to the inks) were printed, each was compared to an offset press proof which was printed in accordance with the recommended Specifications for Web Offset Publications (SWOP) . A Minolta Chroma Meter CR-121 was used to measure the "AE" values of each print which determined whether an allowable color tolerance had been established. In conclusion, the study rejected the stated hypothesis of; there is no significant difference, defined as a "AE" value of less than six (allowable color tolerance), between an offset press proof produced in accordance with SWOP recommendations, and a halftone gravure print from cylinders produced with the same set of universal films, when using properly extended Group VI gravure inks. Of the ten image areas selected, only two had a “AE" value of less than six. The rejected hypothesis was supported by the suspicion that further addition of clear extender varnish to the gravure inks may not improve the situation. The continuance of this study would be further enhanced by the investigation of the difference, if any, between Group VI gravure inks and the SWOP offset inks in relation to hue, saturation, and brightness.
Library of Congress Subject Headings
Printing ink; Offset printing; Intaglio printing; Photoengraving--Halftone process
Department, Program, or Center
School of Media Sciences (CIAS)
Green, Michael Thomas, "A study of the effects of clear extender varnish modification of gravure inks to produce an allowable color tolerance between a halftone gravure print and a SWOP standard offset press proof in hue, saturation, and brightness" (1987). Thesis. Rochester Institute of Technology. Accessed from
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