Color light, or direct color, is probably most familiar
through its practical application in theater and advertising.
The scientific analysis of the physical qualities (wave length, etc.)
is not the problem of the colorist; it is the concern of the physicist.
When he mixes his colors, he projects them on a screen,
1 on top of or overlapping the other.
In any such mixture where there is overlapping,
it will be obvious that every one of these mixtures
is lighter than any of the mixture parents.
By means of the prismatic lens, the physicist easily demonstrates
that the color spectrum of the rainbow is a dispersion of the white sunlight.
With this he proves also that the sum of all colors in light is white.
This demonstrates an additive mixture.
