Two Colour Theories
A. The Young-Helmholtz Theory
The Young-Helmholtz Theory is a theory of the trichromacy of colour vision, or how photoreceptors in the eyes work to enable colour vision. The two scientists hypothesized that there were three photoreceptors or cones, which were sensitive to particular wavelengths of light. The intensity of the wavelength of light hitting the cones are then transmitted to the brain, where one then perceives a visible colour. These were discovered to translate to the primary colours of red, green, and blue.
If an eye contains a trio of photopigments, any wavelength of light will be able to produce three responses. Because certain wavelengths of light will trigger a better response in one type of photoreceptor, it is best to have at least three photoreceptors so that “each member of the trio elicits the largest response from a different one of the three pigments” (Sekuler and Blake, 283).
B. The Goethe-Hering Theory
The Goethe-Hering Theory suggests that there are six primary colours which have six different photoreceptors. The theory says that there are pairs of primaries: red and green, blue and yellow, and black and white – and the nervous system treats these pairs of primaries as mutually antagonistic. This is because in colour experience, these colours are seen as mutually exclusive: an object will never appear to be both green and red, or both blue and yellow. Thus, this theory demonstrates how the visual system works on a system of colour opponency. It also helps to explain how we can perceive afterimages. Both Goethe and Hering appreciated the fact that the sensations of colour reaching our eyes do not physically originate from the intensity of the wavelength of light hitting our eyes, but are perceived because of how light generates responses from our visual system.
Above is Eward Hering’s colour charts. His charts demonstrate how all colours can be made from a combination of green, red, blue, and yellow. The circle on the left shows the relative mixtures of colour attributes. The circle on the right shows what happens when these colour attributes mix.