Colour vision is the human ability to distinguish between objects based on the wavelengths of the light they emit, reflect or transmit. The human eye and brain together translate light into colour.
- Colour is not a property of electromagnetic radiation, but a feature of visual perception.
- The human eye, and so human perception, is tuned to the range of wavelengths of light that make up the visible spectrum and so to the corresponding spectral colours between red and violet.
- Light, however, is rarely of a single wavelength, so an observer will usually be exposed to a spread of different wavelengths of light or a mixture of wavelengths from different areas of the spectrum.
- An observer’s perception of colour is a subjective process as the eyes and brain respond together to stimuli produced when incoming light reacts with light-sensitive cells within the retina at the back of the eye.
- The perception of colour can be influenced by various factors, such as lighting conditions, surrounding colours, and individual differences in colour perception.
About trichromatic colour vision (Trichromacy)
Trichromatic colour theory explains how the human eye perceives colour.
- Trichromatic colour theory is based on the existence of three types of light-sensitive cone cells in the retina, each responsive to a different range of colours.
- The colours we perceive result from the combined responses of all three types of cones.
- The sensitivity of cone cells forms the physiological basis for trichromatic colour vision in humans.
- The ability to see colour stems from interactions among the three types of cones, with each cone exhibiting a preference for specific wavelengths within the visible spectrum.
- The three cone types are denoted by the initials L (responsive to long wavelengths), M (responsive to medium wavelengths), and S (responsive to short wavelengths).
- L-type cones exhibit the highest responsiveness to light with long wavelengths, favouring wavelengths around 560 nm.
- M-type cones exhibit the highest responsiveness to light with medium wavelengths, favouring wavelengths around 530 nm.
- S-type cones exhibit the highest responsiveness to light with short wavelengths, favouring wavelengths around 420 nm.
Related diagrams
Each diagram below can be viewed on its own page with a full explanation.
References
Colour vision is the human ability to distinguish between objects based on the wavelengths 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; indeed, a person’s perception of colour is a subjective process whereby the brain responds to the stimuli that are produced when incoming light reacts with several types of cone cells in the eye. In essence, different people see the same illuminated object or light source in different ways.