What is color temperature? Definition of color temperature, introduction of color temperature table and white balance.

What is the color temperature? Whether taking photos, photography, publishing or home decoration will be applied to the concept of color temperature. Sometimes, a slight adjustment of the color of the picture or environment can make the artistic conception of the whole picture more prominent. Color temperature is also related to daily life. What color temperature should be used for fluorescent tubes and bulbs at home is also a science. What is color temperature, its origin, standard definition and its relationship with temperature? This article will tell you one by one.

The calculation unit of color change with temperature is K color temperature, which is translated from English color temperature. It is a representation by comparing the color of the light source with the temperature of the black body. The standard of color temperature was first formulated by William Thomson, a British physicist, so the color temperature K number, Creutzfeldt scale, Kelvin scale and so on, which are often heard in photography, are all derived from the name of the producer Kelvin.

Creutzfeldt-Jacob thermometer relates color to temperature, records the light color of "black body" (which can be imagined as metal such as iron or tungsten) at different temperatures, and then works out the relationship between temperature and color according to this phenomenon. For example, when the temperature is lower than 4000K, the light emitted by the black body is light red, then the color temperature of 4000K is light red, and when the temperature is higher than 7500K, it is light blue, that is, the color temperature of 7500K tends to be light blue.

▲ In general cognition, red stands for warm color and blue stands for cool color. However, in fact, the color temperature value of blue, that is, the temperature is higher. As for the color change of the sun, other factors such as atmospheric reflection need to be added, which has nothing to do with the blackbody phenomenon. The above figure is approximate, not absolute. The picture is from Wikipedia.

Relationship between color temperature, Kjeldahl scale and temperature Since Kjeldahl scale mainly records temperature, is Kjeldahl scale related to actual temperature? In fact, just like C in degrees Celsius, K in the Coriolis scale is also a unit of temperature, which is a temperature standard based on thermodynamics. Kelvin used the air temperature at that time to calculate that "absolute zero" was about equal to Celsius? 273 degrees. What about degrees Celsius? 273 degrees is the zero point standard of Kjeldahl temperature scale, and it is 273K at 0 degrees Celsius.

Because of this, there is a certain relationship between Kjeldahl scale and temperature, but in the application field of color temperature such as photography, K number only represents the color of light, and the relationship with actual temperature is no longer inseparable. In addition to the color of light emitted by blackbody heating, there is also a comparison between natural scenery and color temperature K number, which can let ordinary people roughly understand the presentation of color temperature.

▲ Kjeldahl temperature scale and centigrade thermometer. (Source: Wikipedia)

▲ Although red is often associated with fire and heat, the temperature of blue is actually higher than that of red, that is, the "cold color temperature" is "hot" than the "warm color temperature". (Source: CheapStockImage)

Comparison between common scenery and k number:

1700k: matchlight1850k: candle 3000K: common color temperature of halogen lamps and yellow fluorescent lamps 4 100K: moonlight and light yellow fluorescent lamps 5000K: sunlight 6500K: common white light. As mentioned above, the colder the color temperature, the warmer and colder the tone and white balance, and the higher the color temperature k, so with the development of science and technology, most cameras and mobile phones now automatically adjust the white balance, that is, automatically adjust the color temperature under different light, so that the objects in the image can present the correct color.

In addition, mobile phones and cameras will be set like sunny mode, cloudy mode and fluorescent lamp mode, and the image performance will be automatically corrected by adjusting the color temperature. However, sometimes white balance is misjudged. At this time, it is necessary to adjust the color balance manually or through retouching after production. For more color temperature teaching in photography, please refer to the teaching article: palm photography class, about color temperature and white balance.

▲ Shooting the scenery in the afternoon, the overall color temperature is low, showing warm colors.

▲ The adjusted color temperature is higher, and the cold color temperature is not so warm.

▲ Color temperature comparison of electric lamps. Human eyes are very sensitive to light and color, so as long as the color temperature is different, it is possible to see different colors. (Source: Wikipedia)

Color temperature also affects daily life. Besides photography, color temperature also affects daily life. For example, the low color temperature of about 2000K, that is, the warm color temperature, has more red components, which makes people feel very comfortable and sleepy. On the contrary, the cold color temperature above 5300K is close to natural light, and the bright feeling is easy to make people concentrate, which is suitable for office places.

Color temperature can be applied in the fields of imaging, publishing, environmental layout and even breeding. After knowing the color temperature, the sleep quality can also be adjusted with the physiological clock, and the proper application of color temperature can also make the photos more expressive.

▲ White balance and Kjeldahl temperature scale explain the film.