Joel Gray


Most methods used for determining the modulation transfer function of a photographic film require that a sinusoidal intensity distribution object be imaged on the film and the resultant effective exposure modulation compared to the object modulation. This paper describes the investigation of the feasibility of generating a sinusoidal intensity distribution from a crenelate pattern by incoherent spatial filtering using non-monochromatic radiation. Using a Kodak Ektar Enlarging Lens (focal length of 100 mm.) at f/8 it has been found that images may be spatially filtered up to 30 cycles/mm while maintaining a modulation of 62# in white light (tungsten illumination). At this frequency the third harmonic is about 10# of the D.C. level in white light and approaching 13# in blue (Wratten Filter #47) radiation. The magnitude of the third harmonic appears to limit the range of this system from 5 "to 30 cycles/mm if the user can tolerate a 10# third harmonic. At frequencies lower than 30 cycles/mm the third harmonic was considerably less. The average energy required in the object plane for this particular type of system is 70 lumens/cm2- steradian. All work on this project was carried out using a General Electric DVY, 120 volt Quartzline lamp as a source and Kodak Panatomic X film (ASA 40).

Library of Congress Subject Headings

Photographic optics; Optical transfer function

Publication Date


Document Type


Department, Program, or Center

School of Photographic Arts and Sciences (CIAS)


Carson, John


Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in December 2013.

Physical copy available from RIT's Wallace Library at TR220 .G65


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