Kruithof curve

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In colour vision, the colour experience of a given light mixture may vary with absolute luminosity, because both rods and cones are active at once in the eye, with each having different colour curves, and rods taking over gradually from cones as the brightness of the scene is reduced. This means, for example, that light with a colour temperature of 6000K may appear white under high luminance, but appear bluish under low luminance. Under the same low luminance conditions, the colour temperature may need to be adjusted to, say, 4700K, to appear white. This effect leads to a change in colour rendition with absolute illumination levels that can be summarised in the Kruithof curve, named after A. A. Kruithof.^[1]

As the brightness of the scene decreases the brightness of red colours decreases more rapidly than those of blue colours, this is the so-called Purkinje effect.

[edit] References

1. ^ Kruithof AA (1941). "Tubular Luminescence Lamps for General Illumination". Philips Technical Review 6: 65-96. 

[edit] Further reading

• Davis RG, Ginthner DN (1990). Correlated color temperature, illuminance level, and the Kruithof curve. Journal of the Illuminating Engineering Society, 19(1):27-38.

[edit] External links

• The Color of White: Is there a "preferred" color temperature for the exhibition of works of art?
• Daylight: Is it in the eye of the beholder?