Abstract

When red and green stimuli are alternated at some appropriate frequency, we perceive flicker. The flicker can be increased or decreased by changing the ratio of the two radiances; some particular ratio gives minimum flicker. When an adapting field of a certain color is applied, the ratio must be changed in order to obtain the minimum flicker, owing to selective chromatic adaptation. A red adapting field, for example, causes greater sensitivity loss for red compared to other spectral ranges. Thus the radiance ratio should be altered so as to increase the radiance of red stimulus over the green one. Factors H_R and H_G are introduced which specify the ratio change caused by the red and green adapting fields, respectively. A large H_R is especially characteristic of normal color vision, and virtually zero H_R is obtained for color defectives. Thus H_R, in combination with H_O, which specifies the radiance ratio with no adaptation, provides a new method of discriminating color defectives from normals and distinguishing types of defects. The present investigation shows that the discrimination among the three groups is very clear and that no misclassification occurs. However, dichromats are not distinguished from anomalous subjects; further investigation is needed concerning that point.

© 1968 Optical Society of America

Two-Color Threshold as Test of Color Vision*

Robert M. Boynton and Mahlon Wagner
J. Opt. Soc. Am. 51(4) 429-440 (1961)

Flicker Heterochromatic Threshold-Reduction Factor with Two or More Flickering Fields

Mitsuo Ikeda
J. Opt. Soc. Am. 61(2) 261-266 (1971)

Flicker photometric study of chromatic adaptation: selective suppression of cone inputs by colored backgrounds

A. Eisner and D. I. A. MacLeod
J. Opt. Soc. Am. 71(6) 705-718 (1981)

Residual Red-Green Discrimination in Dichromats*

Horst M. O. Scheibner and Robert M. Boynton
J. Opt. Soc. Am. 58(8) 1151-1158 (1968)

Photopic Mechanisms of Early Dark Adaptation*

Edward J. Rinalducci
J. Opt. Soc. Am. 58(5) 690-696 (1968)