What are primary colors and primary colors?

Primary colors, also known as primary colors, are the basic colors used to mix other colors. The purity of primary colors is the highest, purest and most vivid. Most colors can be mixed, and other colors cannot be mixed with three primary colors.

The three primary colors are divided into two categories, one is the three primary colors of color and light, and the other is the three primary colors of pigment.

The picture on the left shows the three primary colors of light, and the picture on the right shows the three primary colors of pigment.

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.

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 presented by the object is the remaining part of the light source after being absorbed by the pigment, so its color quality principle 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.

Application and practice

Art textbooks talk about the use of painting pigments. Because of the long history of art teaching materials, most teaching materials and works still call red, yellow and blue the three primary colors. However, the situation in art practice and production operation is not consistent with what the textbook says. 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.

To sum up, whether from the definition of three primary colors or the verification of practical application results, it is enough to show that it is obviously outdated for art textbooks to still call red, yellow and blue three primary colors.