136. Considering the circuit of the colors which we are able to produce
with our pigment-materials, the question arises, What contrasts of
color are the strongest? what interval in the Scale of Colors gives
us the strongest possible color-contrast? Producing the twelve colors
in the values of their greatest intensities, and as intense as
possible, and setting the tones in a circuit and in their natural and
inevitable order, you will observe that the greatest color-contrast
is the contrast between colors at the interval of the seventh: for
example, the contrasts of Red and Green, or Orange and Blue, or Yellow
and Violet. The colors at the interval of the sixth are less strong
in contrast. The contrast diminishes gradually as we pass from the
interval of the seventh to the interval of the second. The contrast of
colors at the interval of the seventh, the greatest possible contrast,
is called the contrast of the complementaries. In estimating intervals
we count the colors between which the intervals occur.