The complementary wavelength lc is determined
as follows:
All colors do not have a dominant
wavelength. These colors are called non-spectral. For example the
color Q (see figure above) does
not have a dominant wavelength since the line from W
to Q when extended meets the
purple line in L. In such cases,
the line is extended in the opposite direction and when it meets the visual
spectrum at lc, that wavelength
is called the complementary wavelength for the color. In this case, the
wavelength of lc is the complementary
wavelength of Q. Thus mixing
lc with Q
will help us to get the achromatic color W.
