We know that the main purpose of developing a colorimeter is to detect the color of a product and control its color quality. To better analyze and manage color information, understanding color is essential. The change of color is closely related to color. To learn color, we first need to know what the three primary colors of color are.
The colorimeter detects product color based on its three element principle of color and complementary color principle. The essence of the three primary colors is independence, and no color in the three primary colors can be synthesized using the other two colors. In addition, the three primary colors, as the basic colors of color, can be mixed into various colors through color gamut. In the process of color perception formation, the color of the light source is related to three factors: the light source, the eyes, and the brain. Therefore, the selection of the three primary colors of color light involves factors such as the wavelength and energy of the light source, and the spectral response range of the human eye. This is also a detail that must be paid attention to during the development process of colorimeters.
However, from an energy perspective, the mixed brightness superposition of colored light requires that the mixed colored light must be brighter than the various colored lights before mixing. Only colors with lower brightness can be mixed as the primary color to produce a larger number of colors. Otherwise, using colors with higher brightness as the primary color will make them even brighter when added together, and thus it will never be possible to mix colors with lower brightness. In addition, we also know that the three primary colors are distributed in different regions of the visible spectrum. If they are concentrated in a certain region, it will prevent them from mixing more color light.
In the white light dispersion experiment of the colorimeter, we can observe that the red, green, and blue colors are evenly distributed throughout the visible spectrum and occupy a wide area. But if we adjust the angle of the prism in the experiment to narrow the spectrum, we will find that the area occupied by the corresponding color light will also change. In the colorimeter color experiment, significant changes in the three colors of red, green, and blue will be observed on the narrowed spectrum, while the colors of other lights gradually decrease and some are about to disappear. Through experiments, it can be concluded that the wavelength ranges of three types of colored light are: R (600~700nm), G (500~570nm), and B (400~470nm).
In color studies, the entire visible spectrum is generally divided into blue, green, and red regions for research. When mixed with red, green, and blue light, yellow, cyan, and magenta light can be obtained respectively. Pink light is not present in the spectrum, and we call it an out of spectrum color. If we mix these three colors of light in equal proportions, we can obtain white light; By mixing these three colored lights in different proportions, multiple different colored lights can be obtained.
Because the colorimeter is an instrument developed to simulate the principle of human eye color perception, the visual physiological characteristics must not be ignored when analyzing color light and the three primary colors. When the human eye is looking at objects, there are three types of color sensitive cells in the retina - red sensitive cells, green sensitive cells, and blue sensitive cells, which are sensitive to red, green, and blue light, respectively. When one of the color sensitive cells is strongly stimulated, it will cause the excitation of that color sensitive cell, resulting in the sensation of that color. Similarly, in the process of measuring color with a colorimeter, red is also received inside the instrument Color light stimulation will send a red message to the microprocessor of the instrument. The three types of color sensing cells in the human eye have the ability to combine colors. When a monochromatic light stimulates the human eye, the human eye's color sensing cells can break it down into three monochromatic lights: red, green, and blue, and then mix them into one color. It is precisely because of this color matching ability that we can recognize a wider range of colors besides red, green, and blue.
In summary, we can determine that there are three basic colors in colored light, namely red, green, and blue. These three colors of light are not only the main colors obtained by decomposing white light, but also the main components of mixed colors, and can match the spectral response range of human retinal cells, which is in line with the visual physiological effects of the human eye. These three colors are mixed in different proportions to obtain almost all colors in nature, with a large color gamut; Moreover, these three colors have independence, and one of the primary colors cannot be mixed with other primary colors. Therefore, we call red, green, and blue the three primary colors of color light. In order to unify understanding, in 1931, the Commission on Illumination (CIE) established the wavelengths of the three primary colors as λ R=700.0nm, λ G=546.1nm, and λ B=435.8nm. In color studies, for the purpose of qualitative analysis, white light is often regarded as synthesized by adding equal amounts of the three primary colors of red, green, and blue.
There are many aspects related to color and primary colors in the use of a colorimeter, not just these relatively simple conceptual issues. There are more complex analyses and comparisons, but they are all specialized knowledge involved in the process of using a colorimeter. Therefore, as long as we are familiar with these concepts of color primary colors, it can help us better measure and understand the test results.