Colour vision

Colour vision is the ability of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they emit, reflect or transmit. The human eye and brain together translate light into colour.

  • The human eye, and so human perception, is tuned to the visible spectrum and so to spectral colours between red and violet. Light, however, is rarely of a single wavelength, so an observer will usually be exposed to a range of different wavelengths of light or a mixture of wavelengths from different areas of the spectrum.
  • Colours can be measured and quantified in various ways. But an observer’s perception of colour is a subjective process whereby their brain responds to stimuli that are produced when incoming light reacts with light-sensitive cells at the back of their eye. As a result, different people may see the same illuminated object or light source in different ways.

https://en.wikipedia.org/wiki/Color_vision