What’s Color temperature

Standard unit for color temperature is Kelvin (K) . Technically, color temperature refers to the temperature to which one would have to heat a theoretical "black body" source to produce light of the same visual color . All other lights, since they are but comparisons to a black body radiator, should be referred to as having a correlated color temperature. The higher temperature of black body the more blue part in the spectrum and the less red part in the spectrum. In other word Low color temperature implies warmer (more yellow/red) light while high color temperature implies a colder (more blue) light. For example the color of incandescent lamp is warm white color. The color temperature of it is 2700K.The color temperature of fluorescent lamp is 6500K. The color temperature of flashlight is 5500K

For photography. The Color temperature is the important aspect. The color temperature of Sunlight in a whole day is different. However from 9 am to 4 pm The color temperature of Sunlight is about 5500K.So we call that time color temperature of Sunlight as standard color teperature.

As the reason of Standard color temperature is 5500K. The photograph film and the ccd of digitall camera is made according to 5500K. Appearantly the man-made light which is used for photography should be 5500K. After then the photo which look the same as the nature color.If low color temperature (below 5500K) the color of photo will be more red. If high color temperature(above 6000K) the color of photo will be more blue.the color temperature of a black-body radiator is equal to its surface temperature in Kelvin, Low color temperature implies warmer (more yellow/red) light while high color temperature implies a colder (more blue) light.