What is Color Temperature ?

The unit of color temperature is K (Kelvin). It is is a light source color scale and has important applications in the field of photography, video, publishing and so on. The color temperature of the light source is determined by comparing its colors with theoretical thermal blackbody radiation. When light source color match thermal blackbody radiation, then that Kelvin temperature is that the color temperature of the light source, which directly linked to the Planck’s blackbody radiation law.

The color temperature is most universal indicator for the quality of the light source spectrum, Symbol Tc. The color temperature is to define by absolute blackbody radiation, when the light source radiation in the visible region identical with the absolute blackbody, then the temperature of the blackbody is the color temperature of the light source.

The characteristic of low color temperature light source is more red radiation in the energy distribution, usually referred to as “warm light”. After the color temperature increases, there are more blue radiation in the energy distribution, high color temperature commonly referred to as “cold”. Some commonly used color temperature: standard candle is 1930K (Kelvin units), incandescent light is 2760-2900K, fluorescent 3000K, flash light 3800K, sun at noon 5600K, electronic flash 6000K, blue sky 12000-18000K.