What is CMYK? Autotype four colour (Cyan, Magenta, Yellow, Key color). CMYK and RGB

Many have heard the acronym CMYK, which is used in the field of printing, but don't know how she stands for. To understand what four colors do these letters and what are the properties of this autotype, this article will help you.

In the world of optical illusions

Before you figure out what is CMYK, you should understand the nature of such a miracle as the natural light. Few people think that colors exist only within the system, essential components of which are the audience, the lighting and the subject. In this optical miracles are not over. For example, although pure white light we perceive as colorless, it contains all the colors of the spectrum visible to the human eye. It is his complexity gives the subjects coloring. When white light reaches the object, its surface regardless of its properties, absorbs a specific color. While the rest are reflected and contribute to the viewer's perception of the image will be pale or bright.

Reproduction of text and images on physical media from the point of view of human perception

the Paper often prints, originally white and has the ability to reflect all colors of the spectrum of sunlight that falls on it. The better the quality, the higher the reflective properties of the surface. At the same time a dye is a substance that absorbs a specific color. If he slows beams of all lengths except those that correspond to the red component of the spectrum in sunlight one sees only a dye. If we look at the pigment in the rays from the blue light, it will seem to us black.
When the white paper is applied a variety of dyes, reducing the amount of reflected colors. For example, by coating the paper with a blue pigment, we create a situation where she not only absorbs it.

There are combinations of colors which, when mixed you can get a dye able to absorb all the rays reflected by the paper, i.e. make it black. In particular, it is enough to apply the same amount of Magenta, cyan and yellow pigments.
note that this color model does not need white paint, as it is the color of the paper itself. In those areas of the image where it is needed, no pigments are just not applied, leaving the surface clean.

Subtractive model

Paper and other printed materials — this surface is able to reflect natural or artificial light. Obviously, it is easier to count what the amount in the form of rays has changed its direction to the opposite than how it was absorbed. So, if subtract from the white of 3 primary colors, i.e., the basic RGB components, you get three extra colors CMY.

Why “K”, not “B”

Typically, those who do not know what CMYK is, this abbreviation is confusing. Because as has been said, this color model uses 4 different pigment. Three of them are called by their first letter. In addition, use black color. One version claims that K — abbreviation of the word black. It was used instead of “In” to refer to the film of black color in the printing trade, not to be confused with the same letter of the RGB model (eng. blue). The fact that the professional tsvetokorrektsii manipulate 10 channels RGB_CMYK_Lab and use all of the available color space. Thus, when using abbreviations for four-color autotype, the phrase "channel B" would require clarification, which model is it that would be inconvenient.
There is another opinion. According to this version, “K” — is an abbreviation of the word “key”, i.e. the key plate. They represent a printable form of black paint that is applied on top of the already suffered three previous pigment.
in addition, some specialists are inclined to believe that “K” is the German pronunciation and the meaning of the word kontur. In favour of last version says that traditionally the black film in typography is called the contour.

How to pronounce Russian

Although the CMYK color model is used for a long time, many still do not know how correct is this abbreviation. Experts advise to speak out loud as “si-Em-why-Kay”. In addition, there are guidelines called 4-color autobio “C-Mac», as well as to use the term "full color” or “process inks”.

the RGB, CMYK: what is the difference

If the CMYK scheme is used in typography, the red-green-blue model is used when displayed on TVs, monitors and other displays. As you know? they are made up of pixels, representing small dots, each of which has 3 lights, and depending on the brightness of each glows the right shade of that color.
When you print images from the computer, the printer or an offset machine do it using CMYK inks (cyan, magenta, yellow, key color). In this regard, viewing the images in the RGB scheme may differ significantly from what you get on paper or another physical medium.
Reason is in the method of image conversion from one color scheme to another, which simply can not ensure one hundred percent hit. After all, many shades of RGB simply does not exist and cannot be implemented in the CMYK palette (what colors are key in this system, you already know). They are replaced with the closest shades, however the differences are still quite noticeable even to the naked eye.

Why in the CMYK 4 colors, as RGB uses only 3

As you know, black paint can be obtained by mixing Magenta, yellow, and blue, taken in equal proportions. However, for several reasons, it is necessary to use additional pigment. Reasons why autotype involves the use of black paint, several. Among them:
  • mixing yellow, Magenta and cyan pigments, in practice, create dirty brown;
  • process inks do not provide the richness and stability of the gray areas of the image;
  • when displaying very small black parts of the text or graphics without the use of such pigment increases the risk of insufficiently accurate coincidence of the points of application of the cyan, Magenta and yellow colors;
  • black pigment (typically, conventional carbon black) is much cheaper than other colors;
  • mix 100% yellow, purple or blue pigment at one point in the case of inkjet printing quite strongly wets the paper, it deforms and increases the time required for drying.
the Problems of the latter type arise in the offset printing process. In addition, depending on the device? there is a certain limitation on the amount of colors. Some printers it may even be quite large and reach 260-280 %. It means that “real” the black color of such printing devices can be obtained by mixing pigments impossible. So use another black paint.

What is CMYK printing

When you print on offset or chalcography printing machine, color laser printer, etc. is possible in each point or use a coat of paint of specific thickness, or leaving the substrate clean and intact. Thus, for a halftone image rastiratsa. In other words, it is represented as a set of dots in four colours. The density of their placement determines the percentage of use of each of the colors. Away from physical media (paper, film, etc.) points that are located close to each other are merged, and the human eye sees the desired hue. Screening is:
  • amplitude, when the number of points constant, but varies in their size;
  • stochastic when there is no regular structure of the points;
  • frequency response, involving the preservation of size when changing the number of points.

How not to be disappointed when printing photos on a printer

Today's printers have many apartments. They are used for homework, write coursework, essays, etc. Very often the printer trying to print photos. However, as a rule, such attempts end in disappointment, because a bright picture on the screen turns into faded copy on paper. It's all in the translation of the image from RGB model to CMYK model.
to see how it will look in photos on paper, you can use Adobe Photoshop. In this case, it will be possible to edit the image in order to obtain the best result.

Now you know what CMYK is, as the acronym stands for and what deficiencies it has. Most likely, in the near future in its place will come a more advanced scheme of color that will enhance the quality of image printing.