The Old Theories Tested by Mixture of Three Pigments.
Experiments in mixing the three pigments, red, yellow and blue, to produce the secondaries, orange, green and violet, have been very carefully made with interesting and instructive results. All such experiments are valueless unless made with one accepted set of primaries for the three combinations, because it is self-evident that if we select a vermilion red which is very decidedly an orange red, and choose for our yellow one of the orange yellows, the mixture will more nearly approach a true orange than if a standard red and standard yellow are used. Also in making a violet, if we mix a carmine, which is a violet red, with a decidedly violet blue, of which there are many, the result will be a better violet than the combination of the standard red and blue. So also in the mixing of blue and yellow to make green, a greenish yellow and a greenish blue will necessarily produce better results than the standards. Therefore, to test the matter fairly, the same pigments which are used to coat the standard red, yellow and blue papers have been combined so as to produce the best possible orange, green and violet, and these results when analyzed on the color wheel are as follows:—
The orange made by mixing standard red and yellow pigments in the best proportions is equal to O. 46, W. 2, N. 52. The violet is equal to V. 20, W. 1, N. 79, and the nearest approach to a standard green is shown by disk analysis to be G. 37, W. 7, N. 56, which is better than the violet and nearly as good as the orange.
These experiments show that heretofore when a line of standards of six colors has been prepared from three primaries, red, yellow and blue, even though the purest possible colors may have been selected for the primaries, the secondaries have not been in the same class of colors, and that all of them are very dark broken colors. Therefore, in using educational colored papers based on such a scheme, the pupil has received no correct impressions of the relative values of the several colors involved in pure spectrum scales, but has been shown at the outset a mixture of pure and broken colors as standards.
This is not a matter of opinion regarding best harmonies, because it is easy to demonstrate that less skill is required to combine broken colors harmoniously than pure colors, but it is a choice between truth and error in the early education of color perception.