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6. Complementary Colors and Wave-Lengths

Among the most interesting results of the mixture of different stimuli are the identification of pairs of homogeneous radiations which, with the proper ratio of intensities, yield white. Such complementary wave-lengths can be found in the color-mixture triangle at the two intersections of straight lines, drawn through the central white, with the locus of the spectral colors. It is

Fig. 4b. Frequencies of Complementary Hues

clear from an examination of the triangle that there is a range of spectral colors—in the green—which have no single spectral complementary, the complementaries of either end region of the spectrum being found in the other. Extant data on complementary wave-lengths are unsatisfactory because of indefiniteness in the specification of the white stimulus which was employed. Fig 4a gives a plot of the best values which are available. In