Color temperature is a characteristic of visible light that has important applications in lighting, photography, videographer, publishing, manufacturing, astrophysics, and other fields. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that of the light source. Color temperature is conventionally stated in the unit of absolute temperature, the Kelvin, having the unit symbol K.

The light color of a lamp can be neatly defined in terms of color temperature. There are three main categories here:
Warm White (yellowish white through red) 2700-3000K
Natural White (noon daylight) 3500 to 5000K 
Cool White (bluish white) > 5500 K
Despite having the same light color, lamps may have very different color rendering properties owing to the spectral composition of their light.