After processing the transparencies,
set up a pair of projectors as in Fig 3.
This tells us the Three Primary Color
theories are insufficient, color mixing is much
more complex. We are in fact modulating the light of one color with
the light of another color. This not only produces the sum and the difference
of the two frequencies of light, but also a
whole range of harmonic frequencies. The wavelengths of these make up all the other colors.
