This experiment was an extension of research begun by Alman, Berns, Snyder, and Larsen with the purpose of developing a large set of data on the perception of medium (industrial) size color difference. In the current phase of the research the same experimental procedures were followed. A total of 50 observers were asked to make pass-fail judgements of sample pairs in comparison to an anchor pair that was near neutral with a CIELAB color difference of 1.0 unit. Several pairs of various color differences were evaluated along 119 vector directions originating from 19 color centers nominally spaced in CIELAB. There was a total of 32,100 visual observations. The statistical method of probit analysis was used to determine the color difference along each vector that was perceptually equal to the anchor pair under a 6100K daylight simulator. The results of the current phase indicate that CIELAB color differences in the range from 0.78 to 5.11 are perceptually equal to the unit color difference of the anchor pair.
Library of Congress Subject Headings
Colors--Analysis; Color vision; Colorimetry; Physiological optics; Probits
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Reniff, Lisa, "Visual determination of color differences using probit analysis: Phase II" (1989). Thesis. Rochester Institute of Technology. Accessed from
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