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The color of night: Surface color categorization by color defective observers under dim illuminations

Published online by Cambridge University Press:  03 July 2008

JOEL POKORNY*
Affiliation:
Department of Ophthalmology & Visual Science, The University of Chicago, Chicago, Illinois
MARGARET LUTZE
Affiliation:
Department of Ophthalmology & Visual Science, The University of Chicago, Chicago, Illinois
DINGCAI CAO
Affiliation:
Department of Ophthalmology & Visual Science, The University of Chicago, Chicago, Illinois
ANDREW J. ZELE
Affiliation:
School of Optometry and the Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
*
Address correspondence and reprint requests to: Joel Pokorny, Visual Science Laboratories, The University of Chicago, 940 East 57th Street, Chicago, IL. E-mail: j-pokorny@uchicago.edu

Abstract

People with normal trichromatic color vision experience variegated hue percepts under dim illuminations where only rod photoreceptors mediate vision. Here, hue perceptions were determined for persons with congenital color vision deficiencies over a wide range of light levels, including very low light levels where rods alone mediate vision. Deuteranomalous trichromats, deuteranopes and protanopes served as observers. The appearances of 24 paper color samples from the OSA Uniform Color Scales were gauged under successively dimmer illuminations from 10 to 0.0003 Lux (1.0 to −3.5 log Lux). Triads of samples were chosen representing each of eight basic color categories; “red,” “pink,” “orange,” “yellow,” “green,” “blue,” “purple,” and “gray.” Samples within each triad varied in lightness. Observers sorted samples into groups that they could categorize with specific color names. Above −0.5 log Lux, the dichromatic and anomalous trichromatic observers sorted the samples into the original representative color groups, with some exceptions. At light levels where rods alone mediate vision, the color names assigned by the deuteranomalous trichromats were similar to the color names used by color normals; higher scotopic reflectance samples were classified as blue-green-grey and lower reflectance samples as red-orange. Color names reported by the dichromats at the dimmest light levels had extensive overlap in their sample scotopic lightness distributions. Dichromats did not assign scotopic color names based on the sample scotopic lightness, as did deuteranomalous trichromats and colour-normals. We reasoned that the reduction in color gamut that a dichromat experiences at photopic light levels leads to a limited association of rod color perception with objects differing in scotopic reflectance.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2008

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References

REFERENCES

Boynton, R.M. & Olson, C.X. (1987). Locating basic colors in the OSA space. Color Research and Application 12, 94105.CrossRefGoogle Scholar
Breton, M. & Cowan, W. (1981). Deuteranomalous color matching in the deuteranopic eye. Journal of the Optical Society of America 71, 12201223.CrossRefGoogle Scholar
Frome, F.S., Piantanida, T.P. & Kelly, D.H. (1982). Psychophysical evidence for more than two kinds of cone in dichromatic color blindness. Science 215, 417419.CrossRefGoogle ScholarPubMed
Montag, E.D. (1994). Surface color naming in dichromats. Vision Research 34, 21372151.CrossRefGoogle ScholarPubMed
Montag, E.D. & Boynton, R.M. (1987). Rod influence in dichromatic surface color perception. Vision Research 27, 21532162.CrossRefGoogle ScholarPubMed
Müller, M., Cavonius, C.R. & Mollon, J.D. (1991). Constructing the color space of the deuteranomalous observer. Documenta Ophthalmologica Proceedings Series 54, 377387.CrossRefGoogle Scholar
Nagy, A.L. (1980). Large-field substitution Rayleigh matches of dichromats. Journal of the Optical Society of America 70, 778784.CrossRefGoogle Scholar
Nagy, A.L. & Boynton, R.M. (1979). Large-field color naming of dichromats with rods bleached. Journal of the Optical Society of America 69, 12591265.CrossRefGoogle ScholarPubMed
Pokorny, J., Lutze, M., Cao, D. & Zele, A.J. (2006). The color of night: Surface color perception under dim illuminations. Visual Neuroscience 23, 525530.CrossRefGoogle ScholarPubMed
Scheibner, H.M. & Boynton, R.M. (1968). Residual red-green discrimination in dichromats. Journal of the Optical Society of America 58, 11511158.CrossRefGoogle ScholarPubMed
Smith, V.C. & Pokorny, J. (1977). Large-field trichromacy in protanopes and deuteranopes. Journal of the Optical Society of America 67, 213220.CrossRefGoogle ScholarPubMed
Smith, V.C., Pokorny, J. & Swartley, R. (1973). Continuous hue estimation of brief flashes by deuteranomalous observers. American Journal of Psychology 86, 115131.CrossRefGoogle ScholarPubMed