K is for Kelvin
Most people, ok, maybe just me, associate the term Kelvin with temperature. Zero degrees Kelvin is ‘absolute zero,’ the coldest possible temperature when molecules cease to vibrate.
However, Kelvin – and temperature – are terms also applied to the quality of light.
“Temperature” can be applied to color because both relate to the radiation of light from ‘black bodies’ of particular temperatures. [A black body is a hypothetical object that absorbs all electromagnetic radiation, including light, that strikes it.]
While a black body absorbs all radiation striking it, it will also radiate light depending on its temperature.
A black body at a temperature below about 4000 degrees Kelvin (K) appear reddish. At temperatures greater than 7500 K, black bodies appear bluish. Daylight has a color temperature of about 5600 K.
Modern digital cameras and photo software can adjust the temperature of an image, which will enhance blues or reds in a photo to make it feel cooler or warmer.