Fig. 5.
The above remarks apply to both simple and complex colours, and the complex colours are always dichromes, being governed by another physiological fact, which is: That the vision is unable to simultaneously distinguish more than two colours in the same beam of light. The order of their association is definite, and may be described by saying that the combined two are always adjacent in their spectrum order, red and violet being considered adjacent for this purpose. It follows that all complex colours are binaries, and the only possible combinations are as follows:—
Red with Orange.
Orange with Yellow.
Yellow with Green.
Green with Blue.
Blue with Violet.
Violet with Red.
Fig. 6.
In the author’s colour nomenclature, a monochrome is qualitatively described by a single term, and a complex colour by a combination of two single terms. For a quantitative description, it is only necessary to add the measured unit value to each term. When there is excess of brightness, or a saddening factor, these also must be quantitatively estimated.
The colours developed by means of these scales are governed by the same law of selective absorption which governs the development of natural colours, any of which can be matched and reproduced by means of their established ray proportions.
