A measure of the color of a light source family member to a black body at an exacting temperature expressed in degrees Kelvin (K).
Incandescent lights have a low color temperature (approximately 2600K) and have a red-yellowish tone;
daylight has a very high color temperature (approximately 6500K) and appears bluish (the most popular fluorescent light, Cool White, rated at 4200K).
Today, the phosphors used in fluorescent lamps can be blended to provide any desired color temperature in the range from 2600K to 6500K.
