Color temperature

Color temperature hue scale

Description

The temperature (in degrees Kelvin) a blackbody radiator would need to have in order to match the color of a light source. A black body radiator uniformly emits an envelope of radiation. The color of its emission continually changes as its temperature increases. A low color temperature (1000 K) indicates a dull red light, a medium temperature (3000 K) gives an orange-red glow while a high color temperature (5000 K) indicates a bright blue-white light. Thus, the color temperature indicates the perceived 'warmth' (red) or 'coolness' (blue) of a light. The color temperature does not indicate the amount of heat given off by the light.

Some light sources and their color temperatures (CT) are:

• Candle flame (1800-2900 K);
• High pressure sodium (2100 K);
• Incandescent 40W (2650 K) and 100W (2900 K);
• Tungsten halogen 50W (3200 K);
• Warm white fluorescence (4000 K);
• Metal halide (3900 K);
• Cool white fluorescence (4200 K);
• Electronic flash, D50 (5000K)
• Bright midday sun, summer (6000 K);
• Hazy sky (7000-8000K);
• Heavily overcast sky (10000K);
• Skylight filter (12000-18000 K)

Synonyms and Related Terms

CT; chromaticity; correlated color temperature (CCT); colour temperature (Br.); Farbtemperatur (Deut.); température de couleur (Fr.); temperatura di colore (It.); kleurtemperatuur (Ned.); temperatura barwowa (Pol.)

Resources and Citations

• Walter C. McCrone, John Gustave Delly, The Particle Atlas, W. McCrone Associates, Chicago, IV, 1972

• Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996

• Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Renssaeler - http://lrc102.lightingresearch.org/nlpip/glossary.cfm

• Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980

• Olympus Microscopy: www.olympusmicro.com/primer/photomicrography/colortemperature.html - source for most color temperature values

• Wikipedia: http://en.wikipedia.org/wiki/Color_temperature (Accessed Sept. 20, 2005)