The concepts of cold light and warm light

Cold light and warm light are defined according to color temperature. When the color temperature exceeds 5000K, the color is blue, giving people a cold feeling, which is called cold light; When the color temperature is below 3000K, the color of light will be reddish, giving people a warm feeling, which is called warm light.

Color temperature is a physical quantity used to define the color of light source in illumination optics. That is, when a blackbody is heated to a certain temperature, and the color of the light it emits is the same as that of the light source, the temperature at which the blackbody is heated is called the color temperature of the light source, or color temperature for short. Its unit is represented by "K".

The light with low color temperature is yellow, such as incandescent lamp, about 2800K, and the light with high color temperature is blue, such as purple light above 9000 K. Generally speaking, the color temperature of standard white light is 6500K, and the white light emitted by CRT is about 5500K K. The effect of increasing or decreasing the color temperature can be simulated by slightly changing the mixing ratio of the three primary colors. The process of changing equipment such as photography, video recording and display by using the principle of color temperature is called color temperature effect.

Extended data

Location of color temperature

Under normal circumstances, from noon 10 to 2 pm, in a clear and cloudless sky, the standard sunlight is about 5200 ~ 5500 K without direct sunlight; The color temperature of news photography lamp is 3200 k; Generally, the color temperature of tungsten lamp and ordinary bulb lamps used in tungsten lamp and photo studios to take black and white photos is around 2800 K; Because of the low color temperature, the photos taken in this case will feel yellow after printing.

Generally, the color temperature of fluorescent lamps is around 7200~8500K, so the photos taken under fluorescent lamps will be blue. This is because the color temperature of the shooting environment and the color temperature set by the shooting machine are different. Generally, it can be adjusted on the printer. But if there are fluorescent lights and tungsten lamp in the shooting scene, we call it a mixed light source, which is difficult to adjust.

Baidu encyclopedia-color temperature

Baidu encyclopedia-lengguang