Find the ratio of RGB in visible light.

Part 2: Color mixing

Monochromatic light additive method

(a), the determination of the three primary colors of color light

The three primary colors are independent in nature, and none of them can be combined with the other two colors. In addition, the mixed color gamut of three primary colors is the largest, and other colors can be mixed by three primary colors in a certain proportion, and the number of colors obtained after mixing is the largest.

In the process of color perception, the color of light source is related to three elements: light source, eyes and brain. Therefore, the selection of the three primary colors of color light involves the wavelength and energy of the light source, the spectral response interval of human eyes and other factors.

From the energy point of view, color light mixing is the superposition of brightness, and the mixed color light must be brighter than each color light before mixing. Only the light with low brightness can be used as the primary color to mix more colors. Otherwise, if the light with high brightness is used as the primary color, their sum will be brighter, so the light with low brightness will never be mixed. At the same time, the three primary colors should be independent, and the three primary colors should not be concentrated in a certain region of the visible spectrum. Otherwise, not only the colors in other areas can't be mixed, but the selected primary color may be mixed with other two colors, losing its independence, not the real primary color.

In the dispersion experiment of white light, we can observe that red, green and blue are evenly distributed in the whole visible spectrum, occupying a large area. If the prism is rotated properly to widen and narrow the spectrum, you will find that the area occupied by colored light has changed. On the narrowed spectrum, red (R), green (G) and blue (B) are three colors.

The color of light is the most obvious, and other colors gradually decline, and some have almost disappeared. The wavelength ranges of these three colors are: R(600~700nm), G(500~570nm) and B(400~470nm). In chromatics, the whole visible spectrum is generally divided into blue region, green region and red region for research.

When red light, green light and blue light are mixed, yellow light, cyan light and magenta light can be obtained respectively. Magenta light does not exist in the spectrum, so we call it outrageous color. If we mix these three colors in equal proportion, we can get white light; By mixing these three colors in different proportions, different colors of light can be obtained.

According to human visual physiological characteristics, there are three kinds of color-sensitive cone cells in human retina-red cells, green cells and blue cells, which are sensitive to red light, green light and blue light respectively. When one of the color-sensitive cells is strongly stimulated, it will cause the excitement of the color-sensitive cells and produce a feeling of color. The three color-sensitive cells of the human eye have the ability to combine colors. When a polychromatic light stimulates the human eye, the color-sensitive cells of the human eye can decompose it into three monochromatic lights: red, green and blue, and then mix them into one color. It is because of this TINT's ability that we can identify a wider range of colors except red, green and blue.

To sum up, we can confirm that there are three basic colors in colored light, and their colors are red, green and blue. These three kinds of colored light are not only the main colored light obtained by white light decomposition, but also the main components of mixed colored light, which can match the spectral response interval of human retinal cells and conform to the visual physiological effect of human eyes. These three colors are mixed in different proportions, and almost all colors in nature can be obtained, and the mixed color gamut is the largest; Moreover, these three colors are independent, and one primary color 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 the understanding, CIE stipulated in 193 1 that the wavelengths of three primary colors are λ r = 700.0 nm, λ g = 546. 1 nm and λ b = 435.8 nm. In the study of chromatics, white light is often regarded as the synthesis of three primary colors: red, green and blue, in order to facilitate qualitative analysis.

(2) Color light additive method

When two or more colors of light are mixed together, it will stimulate people's visual organs at the same time or continuously in a very short time, making people feel new colors. We call this color light mixing additive color mixing. This method of mixing more than two colors to present another color light is called color light additive method.

CIE's color matching experiment shows that neutral white light can be matched when the brightness ratio of red, green and blue is1.0000: 4.5907: 0.0601. Although the brightness values of the three primary colors are not equal at this time, CIE takes the brightness values of each primary color as a unit, so colored light is added. The expression is (R)+(G)+(B)=(W). Red light and green light are mixed in equal proportion to obtain yellow light, that is, (r)+(g) = (y); Red light and blue light are mixed in equal proportion to obtain magenta light, that is, (r)+(b) = (m); Green light and blue light are mixed in equal proportion to obtain green light, namely (B)+(G)=(C), as shown in Figure 2-7. If mixed in unequal proportions, richer mixing effects will be obtained, such as yellow-green, blue-purple, cyan and so on.

Figure 2-7 Schematic diagram of additive color mixing

From the energy point of view of color light mixing, the color mixing equation of color light additive method is:

Where: c is the total amount of mixed color light; (r), (g) and (b) are unit quantities of three primary colors; A, b and g are the component coefficients of the three primary colors. This color mixing equation clearly expresses the three primary colors in polychromatic light.

Judging from the physiological response of human eyes to the physical stimulation of colored light, the mathematical form of colored light plus mixed color is:

Among them: c is mixed color vision; Is the spectral tristimulus value.

In nature and real life, there are many phenomena of color mixing and color enhancement. For example, when the sun rises or sets, some colored light is reflected into space by the thick atmosphere, and some colored light reaches the ground through the atmosphere. Because of the different thickness and position of clouds, people can sometimes see transmitted colored light and sometimes partially transmitted and reflected mixed colored light, which makes the sky rich in color changes.

(3) the essence of addition

Additive method is a coloring method which mixes colored light with colored light to produce new colored light. Each color light involved in mixing has a certain amount of energy. When these colors with different energies are mixed together, the energy of mixed colors can change.

When the colored lights are directly mixed, the energy of the new colored light is the sum of the energies of the colored lights participating in the mixing. As shown in Figure 2-8, two kinds of colored light with the same irradiation area-red light and green light are mixed, and the area after mixing is still the same as that before mixing with monochromatic light, but the energy of light increases, resulting in the brightness of mixed colored light.

(4) additive mixed species

There are two main ways to realize color and light mixing: one is the mixing outside the visual organ, and the other is the mixing inside the visual organ.

1, additive mixing outside the visual organ

Additive mixing outside the visual organ means that colored light has been mixed into new colored light before entering the human eye. The direct matching of color and light is additive mixing outside the visual organ. Various monochromatic lights in the spectrum form white light, which is the most typical additive mixing outside the visual organ. The characteristic of this additive mixing is that the energy of each color light has been superimposed before it enters the human eye, and the stimulation of each primary color light in the mixed color light to the human eye begins at the same time, which is the simultaneous mixing of color light.

2. Additive mixing in visual organs

Additive color mixing in visual organs means that monochromatic light participating in mixing stimulates three color-sensitive cells of human eyes respectively, which makes people produce a new comprehensive color feeling, including static mixing and dynamic mixing.

(1) static mixing

Static mixing refers to the mixing of various colors when reflected light stimulates human eyes at the same time. For example, the juxtaposition of fine color points, the mixed color formed by interlaced monochromatic thin lines is static mixed color, and the reflected light of various colors stimulates the human eye at the same time, which is also the mixed color of color and light. The additive mixing of fine color points in parallel is shown in Figure 2-9 a and Figure 2-9 b.

Due to the limitation of visual acuity, people can't distinguish color points or lines that are too close together and have a small area, but regard them as a mixed color. Fig. 2-9a is an enlarged view of the juxtaposition of yellow dots and cyan dots. The reflected light of yellow and cyan stimulates the color-sensitive cells of human eyes at the same time, which makes people feel that the color is neither pure yellow nor pure cyan, but a mixture of cyan and yellow-green. This is because the color points are too close to each other, and the color sensitive cells of human eyes can't distinguish them, which leads to comprehensive color perception.

Figure 2-9 a Static Mixed Color Figure 2-9 b Empty Mixed Color Composition

(2) Dynamic mixing

Dynamic mixing refers to the mixing of reflected color light by human eyes when various colors are dynamic, such as when the color wheel rotates rapidly. The reflected light of various color blocks will not appear in human eyes at the same time, but one color light disappears and the other color light appears, which stimulates the color sensitive cells of human eyes alternately. Because of the persistence of human vision, people's perception of color is mixed.

The reason why the human eye can see the object clearly is that the light reflected or transmitted by the object enters the human eye under the illumination of light, which stimulates the optic nerve and causes visual reaction. When the object is removed from the eyes and the stimulation to the human eyes disappears, the shape and color of the object will not disappear immediately with the removal of the object, and it can stay in the eyes for a short time, about110 second. The brief stay of the shape and color of an object in the human eye is called visual persistence. It is precisely because of this phenomenon of visual persistence that people can enjoy the continuous pictures of movies and TV. The phenomenon of visual persistence is a manifestation of optical illusion.

The persistence of human vision is the physiological basis of dynamic mixing of color and light, as shown in Figure 2- 10.

Paint red and green evenly on the turntable at intervals according to the ratio of 1: 1. Turn the turntable quickly, and you can see that the color on the turntable is yellow instead of red and green. This is because when the turntable rotates rapidly, if the red reflected light enters the human eye, it will stimulate red blood cells. When the red color changes, the green reflected light enters the human eye and stimulates the cells sensitive to green. At this time, the stimulation to red blood cells did not disappear, and it continued to stay110 seconds. At this time, red blood cells and green cells are excited at the same time, resulting in a comprehensive yellow feeling. The faster the color wheel rotates, the more thorough the mixing will be.

Dynamic mixing is the sequential stimulation of mixed colors to human eyes, so it is also called color-light sequential mixing.

Figure 2- 10 Dynamic Mixing of Color Lights

Usually, the human eye can correctly observe and judge the state of external things, such as size, shape, color and so on. However, if the color distribution of commodity packaging is too miscellaneous, the color area is too small or the alternating speed of multiple colors is too fast, it will affect the discrimination ability of human eyes and make the observed colors different from the actual ones.

(5) the law of color and light mixing

1, the law of continuous change of color and light

In a mixed color composed of two colors, if the light of one color changes continuously, the appearance of the mixed color also changes continuously. Through the unequal mixing experiment of color and light, we can observe the continuous change of this mixed color. Red light and green light mix to form yellow light. If the green light remains unchanged, the intensity of the changed red light will gradually weaken, and we can see various mixed colors from yellow to green. On the contrary, if the red light remains unchanged, the intensity of the changed green light will gradually weaken, and we can see various mixed colors from yellow to red.

2, complementary color method

In the experiment of color-light mixing, we can see that white light can be obtained by equal mixing of three primary colors. If red light and green light are mixed first to get yellow light, and then yellow light and blue light are mixed, white light can also be obtained. White light can also be obtained by mixing other colors. If you mix two colors of light to get white light, these two colors are called complementary colors, and these two colors are called complementary colors.

Complementary color mixing has the following rules: each color light has its own complementary color light, and a certain color light is mixed with its complementary color light in an appropriate proportion to produce white light. There are three basic complementary colors: red-cyan, green-magenta and blue-yellow.

An important property of complementary color is that the light of one color is absorbed when it shines on the object of its complementary color. If a yellow object is illuminated by blue light, it will appear black. As shown in figure 2- 1 1.

Figure 2- 1 1 Absorption of Complementary Color Light by Objects

Using this principle, we can use its complementary color to control a certain color light. If the green color is controlled, the reflectivity (transmittance) can be controlled by adjusting the concentration of the magenta pigment layer to obtain appropriate intensity.

3. Intermediate color law

The main content of the law of intermediate color is that any two non-complementary colors are mixed to produce intermediate color. Its color depends on the relative energy of two colors, and its brightness depends on their distance in tone order.

The most typical example of the intermediate color produced by the mixing of any two non-complementary colors is the proportional mixing of three primary colors, in which the intermediate color can be obtained as follows: (r r)+(g) = (y); ); (G)+(B)=(C)； (R)+ (B)= (M). Other non-complementary colors can be mixed to produce intermediate colors. The orange-red light on the color ring is mixed with cyan light, and the position where the intermediate color is produced is on the connecting line between orange-red light and cyan light. Its color is determined by the energy of orange-red light and turquoise light: if the intensity of orange-red light is large, the middle color is orange, otherwise it is turquoise. Its brightness is determined by the position of the mixed two-color light on the color ring: the closer the two-color light is, the closer the middle color is to the edge of the color ring and the closer it is to the spectral color, so it is more vivid; On the contrary, the generated intermediate color is close to the central white light, and the brightness decreases.

4. Law of substitution

Light with the same color and appearance has the same effect in color and light mixing, regardless of whether their spectral components are the same or not. All visually identical colors are equivalent. That is, similar colors are still similar after mixing.

If the color light A=B and C=D, then: a+c = b+d.

The substitution law of color and light shows that as long as the colors are similar in feeling, they can replace each other and the visual effect is the same. Let A+B = C. If there is no direct colored light B and X+Y=B, then according to the substitution law, C can be realized by A+X+Y = C. The mixed colored light produced by the substitution law has the same visual effect as the original mixed colored light.

The substitution law of color and light mixing is a very important law. According to the replacement law, various required colored lights can be generated or replaced by adding colored lights. The substitution law of color light makes the application significance of metamerism more clear.

5, brightness addition law

The total brightness of a mixed color composed of several colors is equal to the sum of the brightness of various colors that make up the mixed color. This law is called the brightness addition law of colored light. The brightness addition law of colored light reflects the energy superposition relationship when colored light is mixed, and embodies the essence of colored light addition.

The above five laws are the basic laws of color and light mixing. From these laws, we can see that all kinds of colors in nature can be produced by mixing the three primary colors in various proportions. If you are familiar with the basic law of color light mixing, you can generally know what kind of color light a complex color light is composed of several primary colors, or what kind of color light will be formed when several simple colors are mixed. This is of great significance to the design of packaging color and the analysis of color draft.

Two-color subtractive method

Three primary colors of (1) pigment

All kinds of objects have different colors under the light. The colors of many objects are painted with pigments. Any substance that can make colorless objects color and colored objects change color after coloring is called pigment. Pigments can be organic or inorganic. Pigments can be divided into dyes and pigments.

Pigment and shadow are completely different substances, but they both have many colors. Among the colors, red, green and blue are the most basic primary colors. Among many pigments, how many basic primary colors cannot be mixed with other pigments, but can they be made into other pigments? Through the experiment of pigment mixing, it is found that the color gamut range of red, green and blue pigments with the same three primary colors of color light is not as wide as that of color light mixing. Any two pigments, red, green and blue, when mixed in equal amounts, can absorb most of the radiation and appear dark or black with a certain color tendency. From the energy point of view, when the pigments are mixed, the light energy decreases, and the color after mixing is inevitably darker than that before mixing. Therefore, pigments with low lightness cannot be blended into bright colors, and only pigments with high lightness can be used as primary colors to mix more colors and obtain a larger color gamut.

From the experiment of pigment mixing, it is found that pigments cyan, magenta and yellow, which can transmit (or reflect) a wider wavelength range, can match more colors. On the basis of this experiment, it is further clarified that cyan, magenta and Huang San pigments can be mixed in different proportions to obtain the maximum color gamut, but these three pigments themselves cannot be mixed with the other two primary colors. Therefore, we call cyan, magenta and yellow the three primary colors of pigments.

It should be noted that in packaging color design and color reproduction, the three primary colors of pigments are sometimes called red, yellow and blue, where red refers to magenta (magenta) and blue refers to cyan (lake blue).

(B) Colorant deduction method and its essence

Color is the inherent optical characteristic of the chemical structure of an object. All objects are colored by objective light reflection. The so-called "subtractive color" means that adding a primary color pigment will subtract a primary color light (complementary color light) from the incident light. Therefore, when pigments are mixed, one or more monochromatic lights are subtracted from polychromatic lights to present another color, which is called subtractive color method.

A b

Figure 2- 12

We take the ideal color filter illuminated by colored light as an example to illustrate. When a beam of white light illuminates the magenta filter, as shown in Figure 2- 12a. According to the properties of complementary colors, magenta filter absorbs G in R, G and B, and transmits the remaining R and B, thus appearing magenta. Figure 2- 12b shows the superposition of cyan and magenta pigments in equal proportions. When white light irradiates cyan and magenta filters, cyan filters absorb R, magenta filters absorb G, and finally only B is left, that is, cyan and magenta pigments are mixed in equal proportion to appear blue, and the expression is: (C)+(M)=(B). Similarly, cyan and yellow pigments are mixed in equal proportion to obtain green, that is, (c)+(y) = (g); The magenta and yellow primary colors are mixed in equal amounts to obtain red, that is, (m)+(y) = (r); While cyan, magenta and yellow are mixed in equal proportions to obtain black, that is, (C)+(M)+(Y)=(Bk). Proportional mixing of tricolor pigments can be shown in Figure 2- 13.

Fig. 2- 13 schematic diagram of subtractive color mixing

Cyan, magenta and yellow are the most basic colors used to prepare other colors in pigments, which are called primary colors or primary colors. Intermediate color is a mixture of two primary colors, which is called secondary color. Red pigment can be considered as a mixture of yellow pigment and magenta pigment, that is, (r) = (m)+(y); Similarly, the green pigment is (g) = (c)+(y); The blue pigment is (B)=(C)+(M). In this way, when analyzing the color formation principle of intermediate color, the intermediate color of pigment can be expressed by primary color. Composite color is a mixture of three primary colors.

Pigment coloring is due to the selective absorption of complementary color components in incident light and the reflection or transmission of remaining colored light to human eyes. The essence of subtractive method is the selective absorption of a monochromatic light in polychromatic light by pigments, which weakens the energy of incident light. Due to the decrease of color light energy, the brightness of mixed colors decreases.

(3) the changing law of pigment mixing

1, mixing of three primary colors

Black can be obtained by mixing three primary colors in equal proportion, namely:

In the formula, it represents the reflected (transmitted) colored light after the pigments are mixed.

When the three primary colors are mixed in unequal amounts, a composite color can be obtained, and its general form is:

Wherein: C is reduced to mixed pigment; (y), (m) and (c) are the unit amounts of the three primary colors of the pigment; A, b and g are the weight coefficients of tricolor pigments.

Through the color mixing equation, we can understand the proportional relationship of three primary colors pigments in various color mixing, and provide the basis for the correct modulation of pigments.

2. Mixing of primary and intermediate colors

(1) complementary pigment

Black can be obtained by mixing the three pigments in equal proportion, that is, (Y)+(M)+(C)=(Bk). If yellow and magenta are mixed to get intermediate red, and then mixed with cyan, the above formula can be written as: (R)+(C)=(Bk).

In this way, when two pigments are mixed into black, we call them complementary colors, and these two colors are called complementary colors. Its significance lies in adding a red color to cyan to get black; On the other hand, adding cyan to red will also turn black. Besides red and blue are a pair of complementary colors, magenta and green, yellow and blue are also a pair of complementary colors in pigments.

Due to the various changes in the proportion of the three primary colors, there are many colors that constitute the complementary color relationship, not limited to the above pairs. As long as the two pigments are mixed to form black, they are a pair of complementary pigments. Any pigment has its corresponding complementary color.

Complementary colors are widely used in pigment mixing. For example, in painting, when a certain color on the screen needs to be darkened, it is not necessary to use black, just draw the complementary color of the original color there. In the process of color printing, special attention should be paid to the use of complementary colors when calling special ink colors. When calling a brighter light color, if the complementary color is not added properly, the ink color will darken.

(2) Intermittent colors are mixed with their non-complementary colors

Intermittent colors and their complementary colors mix to appear black, while the mixed color phenomenon of intermediate colors and non-complementary colors is more complicated. In order to better explain this phenomenon, it is assumed that the primary color pigment of 1 unit can completely absorb the complementary color light of 1 unit. Taking the superposition of ideal red filter and yellow filter as an example, when 1 unit white light is incident, the coloring process is shown in Figure 2- 14, and the expression is as follows:

① The 1 red filter with unit thickness and the 1 yellow filter with unit thickness overlap;

{(Y)+(M)}+(Y)=2(Y)+(M)T(R) red

② The 1/2 red filter with unit thickness and the 1/2 yellow filter with unit thickness overlap;

{ 1/2(y)+ 1/2(m)}+ 1/2(y)=(y)+ 1/2(m)t 1/2(r)+65438。

③ The 1/4 red filter with unit thickness and the 1/4 yellow filter with unit thickness overlap:

{ 1/4(y)+ 1/4(m)}+ 1/4(y)= 1/2(y)+ 1/4(m)t 1/4。

When the primary colors of intermediate colors and non-complementary colors are mixed, not only the lightness and saturation, but also the hue changes with the different concentrations. When the concentration (thickness) of mixed pigment is large, it presents the hue of intermediate color; When the density decreases, it becomes a mixed tone of intermediate color and primary color.

(3) Intermittent colors are mixed with each other

When two kinds of intermediate color pigments are mixed, the color changes greatly with the different pigment concentrations. When the ideal red filter and green filter are superimposed and white light of 1 unit is incident, different colors will appear with the change of filter thickness. The coloring process is shown in Figure 2- 15, and the expression is as follows:

① The 1 unit of the red filter and the 1 unit of the green filter overlap:

{(y)+(m)}+{(y)+(c)} = 2(y)+(m)+(c)(bk)black。

② The 1/2 red filter with unit thickness and the 1/2 green filter with unit thickness overlap:

{ 1/2(y)+ 1/2(m)}+{ 1/2(y)+ 1/2(c)} =(y)+ 1/2(m)+

③ The 1/4 red filter with unit thickness and the 1/4 green filter with unit thickness overlap:

{ 1/4(y)+ 1/4(m)}+{ 1/4(y)+ 1/4(c)} = 1/2(y)+65438+

Intermittent pigments have deep mixed colors. When the pigment concentration (thickness) is large, it appears black and the saturation is 0. With the decrease of concentration (thickness), the color and lightness increase gradually, and the saturation increases rapidly, and then decreases gradually after reaching a certain level.

This intermittent mixing phenomenon often occurs when the brightness of the light source changes. For an intermittent mixed color sample (the thickness of the pigment layer is constant), when the brightness of the lighting source changes, its hue, lightness and saturation will also change, which has certain guiding significance for the reproduction of printing color and the design of packaging color.

The above are several basic mixing methods of multicolor. In addition, there are mixing methods of primary colors and complex colors, intermediate colors and complex colors, and primary colors and black, all of which can get new complex colors. No matter which mixing method, it is essentially a mixture of three primary colors pigments in equal or unequal proportions. It can be further proved that tricolor pigments can be mixed to produce various colors, which is the theoretical basis for modulating various colors with a small amount of pigments in painting or printing.

The relationship between three kinds of addition and subtraction.

Additive method and subtractive method are aimed at colored light, additive method refers to the addition of colored light, and subtractive method refers to the weakening of colored light.

Additive color method and subtractive color method are two completely different color development methods. Additive method is a method of color matching with light. After the color and light are mixed, not only the color is different from the mixed color, but also the brightness is increased. Subtraction is a method of mixing pigments to produce color. After the pigments are mixed, not only new colors are formed, but also the brightness is reduced. Additive method is a color effect produced by two or more colored lights simultaneously stimulating human optic nerve; Subtraction method refers to subtracting a part of colored light from white light or other polychromatic light to produce a color effect stimulated by another colored light. From the complementary relationship, there are three pairs of complementary colors: R-C; g-M； B-Y. In the color light additive method, complementary colors are added to obtain white; In the pigment subtractive method, complementary colors are added to obtain black.

The three primary colors of color light are red (R), green (G) and blue (B), and the three primary colors of pigment are cyan (C), magenta (M) and yellow (Y). What human eyes always see is colored light, and the determination of the three primary colors of pigments is bound to be related to the three primary colors of light. In the study of human vision, it is shown that there are three color-sensitive cells in the fovea, namely red-sensitive, green-sensitive and blue-sensitive cone cells. All kinds of colors in nature can be considered as the reflection of different stimuli to these three cone cells. Therefore, as long as we effectively control the stimulus amount of the three primary colors of light entering the human eye, we will relatively control the surface colors of various substances in nature. In the additive mixing of colored light, more colors are mixed by light energy of red, green and blue, and the color gamut is the largest. Therefore, we choose cyan to control the red light, which is the complementary color of red and can control (absorb) the red light most effectively. Similarly, choose green complementary magenta to control green light; Choose yellow, the complementary color of blue, to control the blue light. Because cyan, magenta and yellow can easily change the absorption of the three primary colors of red, green and blue by changing their own thickness (or concentration), thus controlling the amount of light of the three primary colors entering the human eye.

Using cyan, magenta and yellow to control the reflected light actually means using them to selectively absorb some spectral colors from the spectrum of the illumination source and complete additive mixing with the remaining spectral colors, which is also the selection and recognition of the three primary colors of color light: red, green and blue. The three primary colors of color and light, red, green and blue, and the three primary colors of pigment, cyan, magenta and yellow, are unified, have a common essence and are two sides of the same thing. It is inevitable that they can all get a larger color gamut, because what shines on the human eye is colored light.

See Table 2-3 for the relationship and difference between color light additive method and color material subtractive method.

Fourthly, design the lightness relationship of the three primary colors in the software.

In CorelDRAW 9.0 (or Photoshop), we can observe the Lab value by giving the RGB value (Figure 2- 16), and the results are shown in Table 2-4.

Figure 2- 16 psychological brightness of yellow Figure 2- 17 brightness of colors in the color circle

As can be seen from the value of psychological lightness L in Table 2-4, the lightness order of colors in the design software is: white, yellow, cyan, green, magenta, red, blue and black. RGB mode is additive mode, and the mixed brightness of color and light increases. The greater the sum of RGB values, the brighter the color. CMY mode is a subtractive mode, and the mixed light energy of pigments is reduced. The larger the CMY value, the darker the color.

From the six-color phase ring (Figure 2- 17), it can be seen that in the additive mode, the brightness of the three primary colors of red, green and blue is low, and the brightness is increased after mixing, and yellow, cyan and magenta with relatively high brightness are obtained; In the subtractive method, cyan, magenta and yellow are the three primary colors with high lightness. After mixing, the light energy decreases, resulting in red, green and blue with relatively low lightness. In the six-color phase ring, the brightness of red, green and blue is the lowest, while the brightness of cyan, magenta and yellow is the highest.

I wonder if it will help you.