What does the color temperature in the camera mean?

This question is very complicated! The so-called color temperature, in short, is expressed quantitatively by Kelvin temperature (K). Kelvin, a famous British physicist, believes that if a blackbody substance 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", it will become different colors due to the level of heat. For example, the thermal stress on the black body will turn dark red when it is equivalent to 500-550 degrees Celsius, yellow when it reaches 1050- 1 150 degrees Celsius, and blue will appear when the temperature continues to rise. The color composition of the light source corresponds to the thermal temperature of the blackbody, and the color temperature of any light is equivalent to the "temperature" when the blackbody emits the same color. This temperature is used to indicate that a certain color light is different from other characteristics, that is, the color temperature. In the process of striking iron, black iron gradually turns red in the furnace temperature, which is the best example of blackbody theory. Color temperature phenomenon is very common in daily life, and I believe people are no strangers to it. Tungsten lamp is yellow because of its low color temperature, and different street lamps also emit different colors. The flame of natural gas is blue because of its high color temperature. The color temperature of cloudless blue sky in Wan Li is about 10000 K, that of cloudy days is about 7000~9000 K, that of sunny days is about 6000 K, that of sunrise or sunset is about 2000 K, and that of candlelight is about 1000 K. At this time, we can easily find a rule: the higher the color temperature, the bluer the light; The lower the color temperature, the redder it is. When the color temperature of a certain color light is higher than other colors, it means that the color light is bluer than other colors, and vice versa; Similarly, when the light of one color is bluer than the light of other colors, it means that the color temperature of this color light is higher, and vice versa. Make the color temperature clear, the latter is better explained. The adjustment of color temperature in camera is called white balance. Because of the different color temperatures under various lights, a piece of white paper in front of the camera lens is not pure white, but has different colors (such as a little yellow at dusk and a little blue on cloudy days), which the camera itself cannot distinguish. So at this time, we have to tell the camera that it is white. As long as the camera restores white things to white, other colors will naturally revert to their original colors. Of course, shooting portraits also depends on the color temperature at that time. Indoor lighting or outdoor natural light? Fortunately, today's cameras have the function of white balance adjustment, which can be adjusted to various color temperature modes such as lighting, sunshine and cloudy days. Restore the real color to the maximum (but it is impossible to completely match the real environment color), and it is impossible to adjust it to automatic white balance (if there is color cast, it can also be post-processed by software).