Color temperature was first introduced by William Thomson 1st Baron Kelvin in 1848 which gave temperature ratings to visible light measured in kelvins(K). Temperature color in film and photography is most commonly known as White balance. Candlelight is at the lowest ratings between 1K-2,000K. Most incandescent lights range between 2,700K-3,300K which are considered warm or red. Sunlight or natural light are more in the 5,000K+ which are considered cool or blue. However, white fluorescent light give of a rating around 4,000K and give of a more greenish light because of its position on the light spectrum.