Biology Reference
In-Depth Information
mixing only three pigment colours: red, yellow and blue, called the
three primaries (green was in general assumed to represent a secondary
colour, since it could be produced by mixing blue and yellow). There
have been many attempts to explain this apparent triplicity of colour
vision. Weale (
1957
) has given an interesting account of trichromatic
ideas in the seventeenth and eighteenth centuries. He emphasizes
the theories of Lomonosow and Palmer, proposed in 1756 and 1777,
respectively. They both suggested that there were three different
types of light and three different types of retinal molecule. Each type
of retinal molecule was thought to be activated by its analogous type
of ray, giving rise to red, yellow and blue sensations
Given the enormous authority of Newton and his convincing
experiments, it appears surprising that both Lomonosow and Palmer
opposed his basic assumption that white light from the sun is a
mixture of innumerable kinds of different rays that are linked to
different hue sensations (see Newton,
1671
/1672, props. 1, 2 and 7).
The acceptance of Newton's assumption leads to a quite different
explanation of the triplicity of colour vision. Thus, it would follow
that the essential cause of the apparent triplicity should be sought
for solely in the visual system. This lead was followed by Young
(
1802a
), who was well acquainted with Newton's ideas. He suggested
that there existed three different kinds of particle or resonator in the
retina which were maximally sensitive to different wavelengths. The
activity of the different resonators was assumed to be independently
conveyed to the sensorium and there give rise to three different kinds
of colour sensations. At first, he assumed that the three primary
activities gave rise to red, yellow and blue in the brain (Young,
1802a
),
but later he chose red, green and violet colours as primaries (Young,
1802b
,
1807
).
Yet, as pointed out by Helmholtz (
1852
), the finding by artists
that all object colours may be reproduced by mixing red, yellow and
blue pigments could not be a basis for colour theory construction,
since the composition of the spectral lights reflected from pigments
could not be adequately controlled. Thus, as already explained by
