Color Perception

This section explains briefly how we perceive color.

Rods and Cones are photoreceptors (or sensors) in the retinas of our eyes. The Fovea is a spot in the eye where these sensors are more densely located. The blind spot has no sensors and is the part of the eye where the optic nerve begins. The optic nerve transmits signals from the sensors to the brain.

Rods are used in low-light conditions and have low resolution. Cones are used in normal-light conditions and have high resolution. The fovea has a very high resolution.

There are 3 types of cones, and each type is sensitive to different wavelengths:

• short wavelength (S)

• medium wavelength (M)

• long wavelength (L)

This, in turn, means that some cones are more sensitive around the wavelengths for red, some around those for blue and some for green.

Therefore, every color can be expressed as a combination of 3 main channels.

This forms the basis for the Trichromatic Theory which states that we perceive color as a 3 channel system.

However, note that we do not perceive color in amounts of red, blue and green.

The Opponent Process Theory states that we perceive color as a 3 channel system, the 3 channels being:

1. Red-Green

2. Blue-Yellow

3. Black-White (luminance)