Two renowned researchers, Thomas Young and Hermann von Helmholtz, contributed to the trichromatic theory of color vision. The theory began when Thomas Young proposed that color vision results from the actions of three different receptors.
Helmholtz later discovered that people with normal color vision need three wavelengths of light to create different colors.
- Helmholtz used color-matching experiments where participants would alter the amounts of three different wavelengths of light to match a test color.
- Participants could not match the colors if they used only two wavelengths, but could match any color in the spectrum if they used three.
- The theory became known as the Young-Helmholtz theory of color vision.
The identification of the three receptors responsible for color vision did not occur until more than 70 years after the proposal of the theory of thrichromatic vision. Researchers discovered that cone pigments have different levels of absorption. Cones are receptors located in the retina that are responsible for vision of both color and detail. The cone receptors differ in absorption amounts due to the amount of opsin amino acids in the receptor. The three different cone receptors are:
- Short-wavelength cone receptors,
- Middle-wavelength cone receptors, and
- Long-wavelength cone receptors.