What does color temperature mean in photography?

Color temperature is a measure of light color of light source, and the unit is K (Kelvin). The most common index of spectral quality of light source. Color temperature is defined as absolute black body. When the radiation of the light source is exactly the same as that of the absolute blackbody in the visible region, the temperature of the blackbody is called the color temperature of the light source. Low color temperature light source is characterized by relatively more red radiation in energy distribution, which is usually called "warm light"; After the color temperature rises, the proportion of blue radiation in the energy distribution increases, which is usually called "cold light". The color temperature of some common light sources is: standard candle light is 1930K (Kelvin-day); Tungsten lamp 2760-2900K；; The fluorescent lamp is 3000 k; Flash 3800 k; The sunshine at noon is 5400 k; Electronic flash 6000 k; The blue sky is 12000- 18000K. Photography often mentions the concept of "color temperature". As we know, the light usually seen by human eyes is composed of the spectra of seven colors of light. But some are blue and some are red. Color temperature is a method specially used to measure and calculate the color composition of light. It was founded by the British physicist Lord Kelvin at the end of 19. He developed a set of color temperature calculation method, the specific standard is based on the wavelength emitted by a blackbody radiator. Generally from noon 10 to 2 pm, the sky is clear and cloudless. 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. The color temperature of ordinary fluorescent lamps is about 7200~8500 K, so the photos taken under fluorescent lamps will be cyan. 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 become a mixed light source, and this film is difficult to adjust.