A psychophysical investigation was carried out to determine the contrast threshold (represented by a density difference) for a spot on a photographic print with a uniform background density. Problems associated with determining a single value which is represenative of the existing density difference between the spot and surround, resulted from the inherent density variation of photographic print material. A series of eighty density difference measurements of the spot and immediatly adjacent surround are presented for prints which had 0, 50, and 100% frequencies of spot detection. A discussion concerning how the eye may be responding in this type of a situation is included.
Library of Congress Subject Headings
Photographic optics; Visual discrimination
Berkovitz, Myron A., "Contrast threshold for a spot on a photographic print" (1962). Thesis. Rochester Institute of Technology. Accessed from
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