What is the concept of reference color?

Reference colors are basic primary colors, that is, three primary colors. Three primary colors are composed of three basic primary colors. Primary colors refer to "basic colors" that cannot be obtained by mixing other colors. Other new colors can be mixed with different proportions of primary colors. If the mathematical vector space is used to explain the color system, then the primary colors can be used as a set of basis vectors in the space and can be combined into a "color space". Because human eyes have photoreceptors of three different colors, the color space we see can usually be represented by three basic colors, which are called "three primary colors". Generally speaking, the three primary colors of superposition type are red, green and blue, and the three primary colors of subtraction type are magenta, yellow and cyan. Tricolor is also an episode in the animation of Digital Baby 3, and there is also a digital art training institution called Tricolor in Beijing.

Brief introduction of tricolor

Three-color light model (English: RGB color model), also known as RGB color model or red, green and blue color model, is an additive color model, which adds red, green and blue colors in different proportions to produce various colors of light.

The main purpose of RGB color model is to detect, represent and display images in electronic systems (such as televisions and computers), but it is also used in traditional photography. Before the electronic age, based on human perception of color, RGB color model has a solid theoretical support.

RGB is a device-dependent color space: different devices detect and reproduce specific RGB values differently, because color substances (fluorescent agents or dyes) and their individual response levels to red, green and blue vary from manufacturer to manufacturer, and even the time of the same device is different.

non-linear

Due to gamma correction, the color output intensity on computer display devices is usually not proportional to the R, G and B values in image files. That is to say, even if the value of 0.5 is very close to half of 0 to 1.0 (full intensity), the light intensity (0.5, 0.5, 0.5) displayed on the computer monitor is usually displayed (1.0, 1.0).

. In the schematic diagram of color light additive method and pigment subtractive method, the left picture shows the three primary colors of color light: red, green and blue; The picture on the right shows the three primary colors of pigment: yellow, magenta and cyan.

The three primary colors of color light refer to red, green and blue, and their corresponding wavelengths are 700 nm, 546. 1 nm and 435.8 nm respectively. The three primary colors of light and objects are different. The three primary colors of light can be mixed in a certain proportion to present various light colors. According to the research results of Thomas Young and Helmholtz, these three primary colors are defined as red, green and blue (equivalent to the color feeling of red, medium green and ultramarine in pigments). The color TV screen is made up of these red, green and blue dots. Mixing these three primary colors in different proportions and intensities can produce various color changes in nature. The three primary colors of pigments and other non-luminous objects are magenta (equivalent to rose and pink), magenta (equivalent to deep sky blue and lake blue) and light yellow (equivalent to lemon yellow). The three primary colors (1781-1868) selected by the British chemist Faust can be mixed into various colors, but they cannot be mixed with black, and can only be mixed with dark gray. Therefore, in color printing, in addition to the three primary colors, a black version should be added to obtain deeper colors. [ 1]

In art, red, yellow and blue are defined as three primary colors, but a proper amount of yellow magenta can set off scarlet (red =M 100+Y 100), and scarlet can't set off red. Blue (blue =C 100+M 100) can be obtained by adding a proper amount of magenta to blue, but dark blue can be obtained by adding green to blue; More colors can be mixed with yellow, magenta and cyan, which are pure and bright. Green mixed with green and yellow (green =Y 100+C 100) is purer and brighter than green mixed with blue and yellow, while the latter is darker. Magenta and blue are pure purple (purple =C20+M80), red and blue can only get gray purple and so on. In addition, from the perspective of integrating other colors, yellow, magenta and cyan are all their primary colors, with richer colors and purer and brighter colors. (In 3D MAX, the three primary colors are red, yellow and blue)

No matter from the definition of three primary colors or the results of practical application, it is enough to show that yellow, magenta and cyan are called three primary colors, which are more appropriate than red, yellow and blue.

Three primary colors classification

By material

Tricolor flag

The light will be brighter and brighter, and the brighter intermediate colors can be obtained by mixing in pairs: yellow yellow, cyan, magenta (or magenta, magenta). Three equal combinations can get white.

Complementary color means that there are no other colors at all, and red and green are mixed into yellow. Because there is no blue at all, yellow is the complementary color of blue. Two equal complementary colors are mixed into white. Red and green are mixed into yellow according to a certain proportion. So yellow can't be called three primary colors.

/kloc-before impressionism appeared in France in the 0 th and 9 th centuries, people used to think that the color of objects was fixed, which was the so-called "inherent color" of objects. Later, impressionist painters boldly proposed that there is no inherent color, and the color of objects changes with the change of light, thus denying the inherent color. Now, some people suggest that we should not deny the intrinsic color, and think that many paintings are colored according to the intrinsic color, and the intrinsic color has the value of existence in painting. What about "true colors"? From a scientific point of view, there is no inherent color, because objects only have a fixed physical structure and have the ability to absorb and reflect light with a specific wavelength, but what color is displayed depends on what kind of light is irradiated.

Under the same white light, in achromatic color's objects, objects that absorb all colored light appear black, and objects that reflect all colored light appear white. Some objects can't decompose white light because of their structural characteristics, but they absorb some white light and reflect some white light at the same time, so they are included in different achromatic series from light gray, gray to dark gray, and these colors are the result of non-selective absorption of white light by objects.

When white light shines on colored objects, these objects selectively absorb and reflect white light, and the reflected spectral components are also different. At this time, people will see objects of different colors. For example, safflower absorbs yellow, cyan, green, blue, purple and other colors in white light, but reflects red light, so it looks red, so people see the color of the object, which is a different color that is not absorbed or absorbed less by the object. When different light colors reflect an object, they will show different colors, and objects that are colorless in the sun will also become colored objects. Cloth that appears green in the sun will turn black in red light, because green cloth only reflects green light, but it appears black in red light because there is no green light reflection. Another example is a piece of white paper, which is white under white light, red under red light and green under green light. If you use red light and green light at the same time, it is yellow. Only the luminous body has its own fixed color, which is not affected by other light and the reflected color of the surrounding environment. In this sense, a non-luminous object has no "intrinsic color", and its color is determined by its own physical structure and surrounding light conditions, so it is called conditional color. When we are sketching in color painting, we should first recognize and pay attention to the expression of conditional color.

Pigment tricolor

Yellow, magenta and cyan are the three primary colors in color printing, the principle and production of color photos, the design and practical application of color printers. Color printed matter is printed with yellow, magenta, cyan ink and black ink, and the printing in four-color printing is a typical example. In the imaging of color photos, the three emulsion layers are yellow at the bottom, magenta in the middle and cyan at the top. All brands of color inkjet printers also print color pictures with yellow, magenta, cyan and black ink cartridges. By definition, primary colors should be able to modulate most other colors, and none of them can modulate primary colors.

Artistic practice has proved that magenta and a little yellow can bring out scarlet (red =M 100+Y 100), but scarlet cannot bring out magenta. Blue (blue =C 100+M 100) can be obtained by adding a small amount of magenta to blue, but adding white to blue is dark blue. More colors can be mixed with yellow, magenta and cyan, which are pure and bright. Green mixed with green and yellow (green =Y 100+C 100) is purer and brighter than green mixed with blue and yellow, while the latter is darker. Magenta and blue are pure purple (purple =C20+M80), red and blue can only get gray purple and so on. In addition, from the perspective of integrating other colors, yellow, magenta and cyan are all their primary colors, with richer colors and purer and brighter colors.

Three primary colors of color TV

The screen of a color TV set is coated with three different phosphors. When the electron beam hits it, one can emit red light, one can emit green light and the other can emit blue light. When making the fluorescent screen, the workers used a special method to alternately arrange the three phosphors on the fluorescent screen bit by bit. No matter where you take out three adjacent points on the screen, you must include a red point, a green point and a blue point. Each point is only the size of a needle tip, so it can't be seen without a magnifying glass. Because it is small and close to each other, when it shines, the naked eye can't distinguish the light emitted by each color point, but can only see three colors of light.

Printing three primary colors

The color of printing is actually the light reflected by the paper we see. For example, we use this combination when we adjust the color when drawing. Pigment absorbs light, not the superposition of light, so the three primary colors of pigment can absorb RGB colors, namely cyan, magenta and yellow (CMY), which are the complementary colors of RGB.

The yellow pigment and cyan pigment are mixed. Because the yellow pigment absorbs blue light and the cyan pigment absorbs red light, it only reflects green light, which is why the yellow pigment and cyan pigment form green.

Through color perception

Excited colors and quiet colors, bright warm colors such as red, orange and yellow are exciting; Green, purple and blue give people a sense of peace.

Light color and heavy color, light color gives people the feeling of light color, and dark color with low lightness gives people the feeling of dullness. The lower heavy color is the upper light color, which makes people feel stable; Light at the bottom and dark at the top, giving people an unstable feeling.

Gorgeous and simple colors, bright and pure colors give people a gorgeous feeling; Colors with low lightness and purity give people a simple feeling.

Forward color and backward color, these two colors are on the same plane, some colors give people a prominent feeling, and some colors give people a feeling of retreating to the rear. The former is called forward color, the latter is called backward color, and general warm colors such as red and yellow have a sense of progress; Green, green and other cool colors have a fading feeling. A small piece of dark color on the shallow foundation gives people a backward feeling, while a small piece of light color on the deep foundation gives people the opposite feeling. The walls and roof of the room faded after painting, and the room felt spacious and tall.

Expansion colors and contraction colors, some colors look bigger than the actual ones, and others look smaller than the actual ones. The former is called expansion color and the latter is called contraction color. The swelling color is consistent with the advancing color, and the warm color and bright color appear large; The contracted color is consistent with the receding tone. Cool colors and dark colors appear small. Small black characters on white background; White characters on a black background look big. People who wear dark and cool clothes look thin; People who wear light and warm clothes look fat.

/kloc-one evening in 0/925, Paccini was reading oil paintings in his study. As the weather became darker and the light became weaker, he found that his eyes felt the color of the picture, which changed with the decrease of luminosity. First, red gradually becomes inconspicuous, and then he can only see blue. In dark light, the red and yellow wavelengths of light make people feel very dark; Blue and green with short light waves feel bright, and the phenomenon that the visual color sensitivity is opposite to that under strong light is called Pacchini phenomenon. Moonlight is the reflection of the sun's light. Its color composition is the same as that of sunlight, but its brightness is about 500% of that of sunlight. In this light, turquoise is easy to be perceived, while red and yellow are difficult to be recognized, so people see red in the moonlight as dark brown, while white objects are cyan, and everything else is turquoise. In fact, the unique color of moonlit scenery is not the change of moonlight spectral components, but the change of human visual perception of different light colors in the spectrum.

Vision also has the same sense of lightness. Looking at gray paper under direct sunlight, the reflected light intensity is many times brighter than that of white paper indoors, but people think it is gray paper. Because people have the memory of observing white paper in the sun, they automatically adjust their visual feelings psychologically.

The constancy of color is also clearly reflected in the concept of "inherent color". When people observe common objects, due to the influence of consciousness, they habitually accumulate according to long-term experience, exclude the influence of light changes and environmental colors on objects, and adjust their visual color perception to make it close to the common colors of objects, such as tending to regard skin as flesh color, leaves as green and sky as blue. This inherent color concept brings a lot of convenience to people's daily work and life, but if it can't be ruled out in some cases, it will bring quite adverse effects to color observation, involving eyes, optic nerve, psychological contrast, complementary color relationship, color adaptation and so on. Color hobbies, color feelings, color aesthetics, etc. Are not limited to the scope of visual attributes, but should be explained by psychological, personality, social awareness and other factors. Only by fully understanding the theme of color can we correctly understand the color phenomenon.

Divide by attributes

Three attributes of color: hue, lightness and purity. Humans can see all kinds of colors, including bright, soft, bright and deep colors. Most colors have three attributes, hue, lightness and purity. Colors can be divided into two categories: colored series and colorless series. All the colors in the color series have these three attributes. Achromatic color series objects are black and white gray objects, which have no hue and purity, but only lightness, but the three attributes of color include color series. It also includes achromatic series, and people can make qualitative and quantitative analysis of any color according to these three elements, because color is produced by the reflection of light waves by objects, and these three elements are actually divided according to the characteristics of reflected light waves.

Tone, brightness, purity

colour

Tone refers to a specific color attribute formed by light with different wavelengths and frequencies. Some people call it color scale, color purity, chromaticity, color difference, color quality, color tone and so on. According to the order of the solar spectrum, the tones are arranged into a ring, which is called a tone ring, and then divided into several main colors according to the equal color difference, namely red, orange, yellow, green, cyan and purple.

light

Brightness refers to the number of light waves reflected by an object; That is; The intensity of light waves; It determines the depth of color; Colors with the same hue have different brightness because of the different number of light waves with the same wavelength; For example; Pink reflects more light waves; The brightness is close to light gray; But less than the red one; The brightness is close to dark gray; Their colors are the same; But the brightness is different; There is another factor that affects color brightness. The sensitivity of human normal vision to different colors of light is inconsistent. People are highly sensitive to yellow, orange, yellow and green, so they think these colors are brighter, but less sensitive to blue, purple and red, so they think these colors are darker. People usually use colors from white to gray to black to divide several brightness levels as standard brightness levels to compare the brightness of other colors.

purely

Purity refers to the purity of the light wave frequency reflected by the object, and the single or mixed frequency determines the brightness of the produced color. This is a foreign word. Due to different translations, it is also translated into: saturation, chromaticity, color purity, chromaticity and color scale. These words have the same meaning. Of course, some translations are confusing and debatable. The purity of color light with single frequency is the highest, and the purity decreases with the mixing or increase of color light with other frequencies. The closer the color of an object is to a certain hue in the series of red, orange, yellow, green, cyan, blue and purple in the spectrum, the higher the purity; On the contrary. The lower the color purity, the closer it is to the colors of achromatic colors, such as black, white and gray.

When we draw, we often compare the differences of several colors. "We should be different in color matching. At this time, we should compare hue, lightness and purity at the same time, not just one or two differences. When two colors are compared with each other, the following eight situations may occur, including various combinations of three attributes.

Theory and application

Application principle

Tricolor flag

Three primary colors of color and light-additive principle

People's eyes recognize colors according to the wavelength of light they see. Most colors in the visible spectrum can be composed of three basic colors of light in different proportions, namely, red, green and blue. When these three lights are mixed in the same proportion and reach a certain intensity, they appear white (white light); If the intensity of all three lights is zero, it is black (dark). This is addition principle, which is widely used in TV sets, monitors and other products that emit light actively.

Pigment tricolor

Three primary colors of pigment-principle of subtractive method

When printing, printing, painting, painting, etc. passively emit light through the reflection of the surface of the medium, the color of the object is the remaining part of the light source after being absorbed by the pigment, so the principle of its color quality is called the subtractive principle. The principle of subtractive color method is widely used in various passive lighting occasions. In the principle of subtractive method, the three primary colors are cyan, magenta and yellow respectively.

Three primary colors of art

The three primary colors of art: red, yellow and blue.

Red, yellow and blue give people a sense of reality and are actually three primary colors.

Art textbooks talk about the use of painting pigments, and the three primary colors are red, yellow and blue.

Three primary colors of artistic color and light-additive principle orange, green and purple

Three primary colors of artistic color pigments. Principle of subtractive method. Red, yellow and blue.

The six-color system composed of three primary colors of art, namely red, yellow, blue, orange, green and purple, gives people a real color feeling and conforms to the objective reality.

Yellow, magenta and cyan are scientifically accurate three primary colors.

Generally speaking, the equal colors of TV are red, green and blue. In artistic practice and production operation, the three primary colors are scientific and accurate. Yellow, magenta and cyan are the three primary colors in color printing, the principle and production of color photos, the design and practical application of color printers. Color printed matter is printed with yellow, magenta, cyan ink and black ink, and the printing in four-color printing is a typical example. In the imaging of color photos, the three emulsion layers are yellow at the bottom, magenta in the middle and cyan at the top. All brands of color inkjet printers also print color pictures with yellow, magenta, cyan and black ink cartridges.