Kelvin

From ColorWiki

An absolute temperature scale used in scientific circles.

The "color temperature" of a light source, monitor or image area, defined in "Kelvin" (K), is the temperature a perfectly black radiating object would be if it glowed that shade of white. Average daylight is standardized at 6500K (Europe) and 5000K (North America). Higher temperatures are bluer, lower temperatures are redder.

Unlike other temperature scales, the term "degrees" is not used in relation to Kelvin. So a temperature is "6000 Kelvin" rather than "6000 degrees Kelvin".