What is CMYK? Four-color autotypy (Cyan, Magenta, Yellow, Key color). CMYK and RGB

Many have heard the abbreviation CMYK, which is used in the printing industry, but do not know how it stands for. To understand what the four colors denote these letters and what properties this autotype possesses, our article will help.

In the world of optical illusions

Before you figure out what CMYK is, you need to understand the nature of such a miracle as natural light. Few people think about the fact that colors exist only within the system, the necessary components of which are viewers, lighting and the subject. On this optical miracles do not end. For example, although pure white light is perceived as colorless, it contains all the colors of the spectrum visible to the human eye. It is its multicomponent that gives color to objects. When white light reaches the object, its surface, regardless of its properties, absorbs specific colors. At the same time, the others are reflected and create a perception of the image in the viewer, which will be faded or bright.

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

Paper, which is often printed, is originally white and has the ability to reflect the full spectrum of colors of sunlight that falls on it. The better its quality, the higher the reflecting properties of the surface. At the same time, the dye is a substance that absorbs a certain color. If he detains rays of all lengths, except those that correspond to the red component of the spectrum, then in sunlight a person sees only such a dye. If we look at the same pigment in the rays from the blue lamp, it will appear to us black.

When different dyes are applied to white paper, the number of colors reflected is reduced. For example, by applying a blue pigment to the paper, we create a situation where it does not absorb only it.

There are combinations of colors, when mixing, you can get a paint capable of completely absorbing all the rays reflected by the paper, that is, making it black. In particular, it is sufficient to apply the same amount of magenta, cyan and yellow pigments.

It should be noted that this color model does not need white paint, since it is the color of the paper itself. In those areas of the image where it is needed, no pigments simply do, leaving the surface clean.

Subtractive model

Paper and other printed materials are surfaces that can reflect natural or artificial light. Obviously, it is more convenient to calculate what its number in the form of rays changed its direction to the opposite, than how much it was absorbed. Thus, if you subtract three primary colors from white, that is, the basic components of RGB, you will get three additional CMY colors .

Why "K" and not "B"

Usually, those who do not know what CMYK is, this abbreviation is puzzling. After all, as already said, this color model uses 4 different pigments. Three of them are named after their first letter. In addition, black color is used. One version claims that K is an abbreviation for the English word black. It was used instead of "B" to denote a film of black color in the printing industry, in order not to be confused with the same letter from the RGB model (English blue). The fact is that professional color correctors manipulate with 10 channels RGB_CMYK_Lab and use all available color spaces. Thus, when applying the abbreviation for a four-color autotypy, the phrase "action with channel B" would require clarification about which of the models in question that would be inconvenient.

There is another opinion. According to this version, "K" is an abbreviation from the word "key", i.e., the key plate. They designate a printing form for black ink that is applied on top of the already applied three previous pigments.

In addition, some experts are inclined to the fact that "K" has a German pronunciation and means the word kontur. In favor of the latest version says that traditionally black film in printing is called contour.

How to pronounce in Russian

Although the CMYK color model has been in use for a long time, many people still do not know how this abbreviation sounds right. Experts advise to say it out loud, like "SM-M-Wye-Kay." In addition, there are recommendations to call a 4-color avatipy "si-mak", and also use the term "full color" or "triad paint."

RGB, CMYK: what is the difference

If the CMYK scheme is used in the printing business, then the red-green-blue model is used when displaying on TVs, monitors and other displays. As is known? They consist of pixels that are small dots, each of which has 3 highlights and, depending on the brightness of each, glows with the appropriate shade of the given color.

When printing an image from a computer, the printer or offset machine does this using CMYK colors (cyan, magenta, yellow, key color). In this regard, viewing the image in the RGB scheme can significantly differ from what you get on paper or on another physical medium.

The reason is the method of transferring an image from one color scheme to another, which simply can not provide a 100% hit. After all, many shades of RGB simply do not exist and can not be implemented in the CMYK palette (which colors are the main ones in this system, you already know). They are replaced by the closest shades, but the differences are still quite noticeable even for the naked eye.

Why there are 4 colors in the CMYK model, and only 3 colors are used in RGB

As you know, black paint can be obtained by mixing purple, yellow and blue, taken in equal proportions. However, for a number of reasons it is necessary to use an additional pigment. The reasons why four-color autotyping involves the use of black paint, a few. Among them:

• The mixing of yellow, magenta and blue pigments in practice creates a dirty brown paint ;
• Triadic colors do not provide saturation and stability of a shade of gray areas of the image;
• When you derive very small black details of text or drawing without using such a pigment, the risk of an inadequate coincidence of the points of application of cyan, magenta and yellow tones increases;
• Black pigment (usually ordinary soot) is much cheaper than other paints;
• Mixing 100% of yellow, magenta or blue pigment at one point in the case of inkjet printing sufficiently wet the paper, deform it and increase the time required for drying.

Problems of the latter type arise in the process of offset printing. Also, depending on the device? There is a certain limit on the amount of paints. For some printers, it can even be quite large and reach 260-280%. This means that "real" black color on such printing devices can not be obtained by mixing pigments at all. Therefore, one more black paint is used.

What is CMYK-printing?

When printing on an offset or silkscreen press, a color laser printer, etc., it is possible at each point to either use a paint layer of a particular thickness, or leave the substrate clean and untouched. Thus, for transmission of halftones, the image is rasterized. In other words, it is represented as a collection of points of four colors. The density of their placement determines the percentage of use of each of the inks. At a distance from the physical carrier (paper, film, etc.), points that are close to each other merge, and the person's eye sees the desired shade. Screening happens:

• Amplitude, when the number of points is constant, but their size differs;
• Stochastic when there is no regular structure of points;
• Frequency, which assumes the preservation of size with a varying number of points.

How not to be disappointed when printing photos on the printer

Today printers are in many apartments. They are used for preparing homework, writing course papers, essays, etc. Very often the printer also tries to print photos. However, as a rule, such attempts end in disappointment, as a bright picture on the screen turns into a faded copy on paper. It's all about translating the image from the RGB model to the CMYK model.

To see how the photo will look on paper, you can use Adobe Photoshop. In this case, you can edit the image in order to get the best result.

Now you know what CMYK is, how this abbreviation stands and what drawbacks it has. Most likely, in the near future it will be replaced by a more perfect color scheme, which will improve the quality of printing images.