What is the color temperature in photography? What is the color temperature?

Color temperature = is the characteristic of visible light, which has important applications in photography, video recording, publishing and other fields. The color temperature of the light source is determined by comparing the color of the light source with the theoretical hot blackbody radiator. The Kelvin temperature when the hot blackbody radiator matches the color of the light source is the color temperature of that light source, which is directly related to Planck's law of blackbody radiation.

The color temperature is expressed in Kelvin, usually in K. The color temperature mentioned in photography has nothing to do with our daily temperature or degrees Celsius. It is a description of the color tone of the photo. In the camera, we can use white balance to adjust the color temperature of the photo. Generally speaking, cameras provide six or more white balance presets so that photos can display various colors.

Due to the different light sources, the color temperature of the photo will be cold and warm. Generally, the color temperature of natural light will be around 4500 K. The higher the value, the colder the photo will be, and the lower the value, the warmer the photo will be.

The function of color temperature is to analyze the content of different color components in light, and its unit is "K". Common color temperatures range from 1000 to 17000 K. For example, the color temperature of candlelight is about 2000K, and that of tungsten lamp for home use is about 2800 ~ 3200k.

The color temperature of beautiful sunrise and sunset is about 3400K, the sunlight at noon is about 5400K, the cloudy day is about 6200K, and the blue sky is about15000 K. The lower the color temperature, the more red components of the light, and the warmer it feels. Conversely, the higher the color temperature, the more blue components of light, and the colder it feels.

Extended data:

The principle of color temperature:

Kelvin believes that if a pure black object can absorb all the heat falling on it without loss, and at the same time release all the energy generated by heat in the form of "light", then the wavelength of its maximum radiation intensity will change with the change of temperature.

For example, when the thermal power of the blackbody is equivalent to 500-550℃, it will turn dark red (the radiation intensity of a certain red wavelength is the largest), and it will turn yellow when it reaches1050-150℃ ... Therefore, the color composition of the light source corresponds to the temperature of the blackbody.

Color temperature is usually expressed in kelvin temperature (k), not in degrees-days. In the process of striking iron, black iron gradually turns red in the furnace temperature, which is the best example of blackbody theory. Usually, the tungsten wire in the bulb we use is equivalent to this black body. The calculation method of color temperature is based on the above principle, and K is used to correspond to the color representing the maximum wavelength of an object when it radiates at a specific temperature.

According to this principle, the color temperature of any light is equivalent to the "temperature" when the black body emits the same color. Color is actually a psychological and physiological function. All color impressions are caused by intermittent spectral reactions on the eyes, so color temperature is only used to express the visual impression of color.

Baidu encyclopedia-color temperature