Colour constancy

Colour consistency is a perceptual ability that enables colours to appear the same as lighting conditions change.

Colour constancy is an extreme case of chromatic adaptation that associates a particular colour with an object regardless of changes in lighting.

  • Colour constancy refers to the perceptual ability to compensate when changes in illumination would otherwise cause things to appear to be different colours.
  • Colour vision relies on colour constancy to enable an observer to perceive the colour of an object as unchanged as levels of illumination and the spectral distributions of light alter.
  • Colour constancy means that a human observer will often not notice when the colour of an object changes as the source of illumination is changed e.g. sunlight to artificial light.
About chromatic adaption
  • Chromatic adaptation is the human visual system’s ability to adjust to changes in illumination in order to preserve the appearance of objects.
  • Chromatic adaptation is responsible for the stable appearance of the colour of familiar objects despite the wide variation of lighting conditions.
  • Chromatic adaption means an observed colour stimulus such as a white surface is judged to remain white even as other projected or reflected colours fall upon it.
  • Chromatic adaption often becomes noticeable when comparing photographs of the same subject in changing lighting conditions. Cameras use white balance to compensate for changes in lighting but two photos taken only minutes apart may render the same subject matter differently.