Standard response functions for protanopic and deuteranopic vision

Abstract

The color matches set up b.v the normal observer can be predicted satisfactorily by three functions of wavelength defining the ICI standard observer. It has been found possihle by a transformation of coordinate system to express these three functions in a form slIch that two of the three pairs 3.1S0 represent the color matches of the two recognized types of red-green-blind observer, the p rotanope and the deuteranope, within the rather small uncertainties to which they are known. The remaining pair of function s represents, within the comparatively large uncertainties to which they are known, the color matches of the tritanope, a more rare type of observer who confuses reddish blue with greenish yellow. These three functions, therefore, serve to re13te the color matches made by dichromats to those made by normal trichromats, and so make conveniently accessible the color confusions of average dichromatic observers. The use of these three functions in the solution of problems arising in the design of tests for colorblindness is illustrated by solution of three sllch problems, a nd t heir connection to theories of color vision is discussed.

Orthogonal Relations and Color Constancy in Dichromatic Colorblindness

“…The table is supported by Figures 1 and 2 which illustrate the main confusion locus and minor confusion loci calculated from CIE colorimetry by Judd [25]. In the reduction form, confused hues are in complementary pairs as are residual hues.…”

“…The basic data on dichromatic vision are the neutral point wavelengths, as listed in Table 1 from several sources [2], [22]–[25], [27]–[33] in three sections for the protanope, deuteranope and tritanope. Each section ends with a Mean.…”

“…These adjusted means were rounded to the nearest integer (493, 498, 568 nm) to be used in CIELUV diagrams in illuminant D65. Each section first lists the well known neutral point wavelengths or wavelength ranges estimated by Judd [25] and Wyszecki & Stiles [2]. Lacking explicit references and illuminants, these data cannot be included in the Mean but are useful for comparisons.…”

“…Figure 1 shows other confusion loci adjacent to the main locus. The confusion loci meet at the confusion point, whose chromaticity coordinates are not exactly known but have been estimated by Pitt [24], Judd [25], and others.…”

“…Means are weighted by number of observers and exclude Judd [25] and Wyszecki & Stiles [2] unsourced estimates. Mean* (under “Deutan”) denotes mean without suspect Hecht data.…”