Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, digital cinematography and other fields. The color temperature of a light source is the temperature of a black body, when heated to varying temperatures, in degrees Kelvin, it becomes incandescent, glowing and radiating visible light. The color of the light emitted changes from red to blue as the temperature of the black body rises. The temperature is calculated in degrees on the Kelvin scale, having the unit symbol of K.