PRINTING GLOSSARY OF TERMS

CMYK

A color model, process colors, that consists of four colors. C-cyan, M-magenta, Y-yellow, K-black or key color. CMYK is used for a full-color printing and is usually denoted as 4+0 (single sided printing) or 4+4 (double sided printing). CMYK color model is used to print colored documents in the offset printing technique and all types of digital printing.

RGB

A color model for generation of pictures on the display of different types of screens. Consists of R-red, G-green, B-blue that create a full spectrum in the virtual world. It is not possible to print in the RGB color scale; therefore, when preparing a file for printing, it is mandatory to change RGB color model to CMYK. When changing RGB to CMYK, the colors change, they need to be additionally processed. In the computer graphics, before starting to work, it is important to determine which working environment will be used – printing or web. It will determine the correct color model – CMYK or RGB and there will be no need for color correction.

Spot color

Pantone Spot color – specific color – is not obtained during printing process by mixing CMYK colors, but while choosing a ready color tone, say, from the Pantone catalogue. Is used in cases when the design requires only one or two specific colors or in cases when a precise color tone has to be obtained that can not be obtained by mixing only CMYK colors. Such colors are, for example, gold, silver, and khaki. If the pantones are used together with CMYK, then four-colored print will become five or six color print, etc. (5+0, 6+0). Spot colors are used only in silk screening or offset printing; it is not possible in digital print.

Vector graphics

Vector graphics is a use of the basic geometrical elements – dots, line segments and polygons – in the computer graphics to depict drawings. The most popular vector programs are Corel Draw (cdr files) and Adobe Illustrator (ai files). Images of the vector graphic are usually drawn using the tools of vector graphics. Lines can be read precisely, and pictures can be enlarged limitlessly, loosing no quality. Vector graphics are also used when writing texts that are changed to curves, and they become objects of the vector graphics.

Raster graphics

Raster graphics is a picture display mode when lines in the screen of a display consist of a separate dots or pixels, where specific color and lightness can be determined for each of them. Seen through the magnifying lens, lines of the raster graphics are not as a curves and not in one color, instead they are serrated, consist of many mini-squares and color scales. The most popular raster graphics programs are Adobe Photoshop (psd files) and MS Paint (bmp files). Raster graphics files are usually created from photos and finished drawings that are later processed by different means. Usually it is not recommended to enlarge pictures, because then the quality will be lost.

Bleeds and crop marks

Bleeds are the parts of the graphic object that are outside the cutting line. Therefore while preparing the work; it is important to create 3-5 mm design bleed over the cutting margin. But crop marks in the graphic arts are used to mark the cutting margins of the printing product. These are small cross marks in the corners of page. Crop marks are also used to mark folding and perforation lines.

Pixel

The smallest element of the picture, in the raster graphics it can be assigned such characteristics as, say, color and brightness.