Abstract

An imagesetter can be calibrated by measuring solid density and using a linearizing program. An alternative method consists of adjusting exposure in order to optimize resolution. This method works well with a rapid access system; however, preliminary tests show that it may not be applicable to a hybrid system. This study had the following purposes: (1) to investigate the differences in response over the halftone range between a hybrid film and a rapid access film on a laser exposure imagesetter, (2) to evaluate the applicability of calibra tion and linearization methods using checkerboard patterns, (3)to determine a better method, if the checkerboard method is not adequate for the hybrid system, and (4) to explain the differences of the two films in terms of their fundamental characteristics. An exposure series of continuous-tone gray scales and a test page with halftone scales were performed on an imagesetter using hybrid film and rapid access film, which were Kodak Imageset 2000 film and Kodak PagiSet film respectively. From the continuous-tone exposure series, it was found that Imageset 2000 film has significandy higher contrast than PagiSet film. A linear relationship was found between laser intensity units of the imagesetter and exposure in terms of energy. The slope of these plots were a function of the laser beam. From the test form's exposure series, it was found that matching the density of the lxl checkerboard to that of 50% reference tint on the UGRA/FOGRA PostScript Digital Control Strip is applicable for calibrating and linearizing common screen rulings within a tolerance of 1 % on PagiSet film. However, maximum density at practical exposure of Pagiset film is too low. Overexposure is needed in order to obtain a satisfied maximum density; and therefore, a linearizing program is required to correct the non-linearity. For Imageset 2000 film, matching the density of the 2x2 checkerboard to that of 50% reference tint on the UGRA/FOGRA PostScript Digital Control Strip is applicable for calibrating and linearizing common screen rulings with a satisfied maximum density. Imageset 2000 film has a slightly lower modulation transfer function than PagiSet film. There was some evidence that showed chemical spread for Imageset 2000 film.

Library of Congress Subject Headings

Laser printing--Evaluation; Laser printers--Calibration; Photography--Films--Evaluation

Publication Date

1996

Document Type

Thesis

Department, Program, or Center

School of Print Media (CIAS)

Advisor

Sigg, Franz

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: Z249.4 .S287 1996

Campus

RIT – Main Campus

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