Definitions of Cotor Terms. 
19 
Pure Color .—A color corresponding- in purity with 
(or, in the case of material colors, closely approximating 
to) one of the spectrum colors. 
Broke?i Color :—Any one of the spectrum colors or 
hues dulled or reduced in purity by admixture (in any 
proportion) of neutral gray, or varying relative propor¬ 
tions of both black and white; also produced by ad¬ 
mixture of certain spectrum colors, as red with green, 
orange with blue, yellow with violet, etc. These broken 
colors are far more numerous in Nature than the pure 
spectrum colors, and include the almost infinite varia¬ 
tions of brown, russet, citrine, olive, drab, etc. They 
are often called dull or neutral colors. 
Fundamental Colors .—The six psychologically dis¬ 
tinct colors of the solar spectrum; Red, Orange, Yellow, 
Green, Blue and Violet. 
Primary Colors. —Theoretically, any of the spectrum 
colors which cannot be made by mixture of two other 
colors. According to the generally accepted Young- 
Helmholtz theory* the primary colors are red, green, 
and violet ; orange and yellow resulting from a mixture 
of red and green, and blue from a mixture of green and 
violet. There is considerable difference of opinion, how¬ 
ever, as to this question, and further investigation of the 
subject seems to be required ; at any rate, authorities 
fail to explain why red may be exactly reproduced (ex¬ 
cept as to the degree of luminosity) by a mixture of 
orange and violet, exactly as yellow results from mix¬ 
ture of red and green or blue from green or violet, green 
being, in fact, the only spectrum color that cannot be 
made by mixture of other colors.* 
*J. J. Muller found that a mixture of the oi’ange and violet rays of the spectrum 
produced a whitish red (Rood, ‘Modern Chromatics,” p. 129). The author of the 
present work, without being at the time aware of this, produced an absolutely pure 
red (but of reduced intensity) by mixture of either orange and violet (orange 63.5, 
violet 36.5 percent.=red 85+white 15 per cent.), or from orange and the violet-red 
which is complementary to green (violet-red 51, orange 49 per cent.), the latter equal¬ 
ing red 89+white 11 per cent; the mixtures being made on a color wheel with Max¬ 
well disks representing the pure colors of the present work. The red resulting from 
either of these mixtures on the color-wheel is far purer than the blue resulting 
from mixture of green and violet, and incomparably more so that the yellow result¬ 
ing from mixture of either red and green or orange and green. Consequently, if the 
same results would come from mixing orange and violet light, it is difficult to under¬ 
stand how red can be a primary color according to the accepted definition. 
