Basic knowledge of color theory (3)

Third, the visual color of the three primary colors

Theory of Color Vision is based on the human eye vision system's color recognition mechanism. Its purpose is to explain or assist researchers in understanding and mastering the visual and color production through such color vision theory. Phenomenon and relationship. After years of research, the theory of color vision can be summarized as the following three theories:

1. Three-component or Trichromatic Theory

2. Opponent-colors Theory

3. Zone Theory of Color Vision

The theory of “visual color three primary colors” was the earliest proposed theory, and it has always been in the dominant position in color science. Since then, “the theory of the color of opposing colors” was proposed. This theory is another one in addition to the theory of visual color three primary colors. Important theories are also valued by the color science community; although these two kinds of color vision doctrines can explain most of the visual color phenomena, there are also the “stage visual color theory” proposed in recent years and accepted by everyone. And this - the doctrine is the synthesis of "theory of the three primary colors of visual color" and "the theory of the color of the opposing colors," the basic concepts, to be combined and complement each other. The detailed contents of these three color vision theories will be explained in detail in the color technology articles. In this article, we will first discuss the theory of "visual color trichromatics."

In 1802, Tomas Young of the United Kingdom discovered that using three colors of red, green, and blue light to produce a variety of colors, he published and proposed the theory of color trichromatics. In 1861, the British Maxwell used the hybrid method of three primary colors of light to produce The first color photograph; this theory reached the end of the 19th century? In 1892, Helmholtz in Germany verified and explained his theory. Therefore, the three-primary theory of visual color is also called Young-helmholtz theory of color three primary colors.

The theory is that the three kinds of visual cells on the human retina are connected with three different types of nerve cells in the cerebral cortex. Each type of cell stimulation causes a sense of primary color. The feelings of red, green, and blue are three colors. This argument has detailed information in the previous article. The reader should have some impressions. When the light reflected by (or transmitted by) the light-irradiated object enters the human visual system, it simultaneously stimulates three different types of cells, and the wavelength characteristics of the light make the total intensity of the three types of cells different. Produce a variety of different colors feel. This theory was proposed by Tomas Young of the United Kingdom. When a certain color sensation occurs, one of the three types of cells will have the most intense stimulation, but the other two types of cells will also produce more stimulation, which means that all three types of cells will be stimulated. One kind of color will have a white light component, that is, there is a sense of lightness. The feeling of brightness is the sum of the brightness sensations provided by the three cells. Later, Germany's Helmholtz added Tomas Young's theory that different parts of the spectrum can cause three different cell stimuli of different strengths and weaknesses. The colors seen in mixed shades are the stimuli of three different cells, and this argument has been proposed. For the eyes to see the red, green, and blue colors than the monochromatic light to get a more reasonable explanation. All in all, any color seen by the eye is the result of a total stimulus after light stimulation of the three visual cells.

The greatest advantage of Young-Helmholtz's color trichromatic theory is that it can fully explain the mixed phenomenon of various colors and solve the problem of color reproduction. For example, the color reproduction of color movies and color televisions are all developed on the basis of this theoretical basis; The hypotheses of the three photoreceptor cells were also proved in the experimental results and laid the basic concept of spectral tristimulus values. This theory can be said to be the root of the development of modern “chromometry”. However, the disadvantage of this color vision theory is that it cannot satisfactorily explain the phenomenon of Color Blindness. Regarding the Color Blindness phenomenon, Helmholtz believes that color blindness is caused by the lack of one (monochrome blind) or two or even three (pan-blind) cone cells, so according to its theory, blindness and greenness Color blindness and blue blindness can exist alone, but in fact all red blind people are almost green blind at the same time, that is to say, people with red blindness are generally unable to distinguish between red and green, which is called red-green blindness; and according to their theory Inferred that red-green blind people should not have a yellow sensation - because red-green blindness is lack of red and green cone cells, and yellow color perception is formed by the induction of red and green cone cells, but in fact red-green The blind person has the same yellow feeling; in addition, according to his theory, three kinds of photoreceptor cells will have a neutral color at the same time - a white or grey feeling. The color blind person lacks at least one of the cone cells and should not have a neutral color. White or gray feel, but even full-blind people have the same feeling of brightness or whiteness. Therefore, there are contradictions and unexplained phenomena in terms of "theory of three-primary color of vision." Therefore, there is another school of color vision theory - Hering's "theory of the color of opposition". As for the "Contradictory Color Theory", it will be discussed and explained in the next article.

(to be continued)