RASTER

The starting and ending point

One of the main features of a print material is the analysis of its images in digital as well as in printed form. As in the digital format the term pixel is established, in print we use raster terms, dot. Each pixel corresponds to a projected pixel, and each raster to a printed dot.

In detail, raster is the dots used in printing to give different color tones. All dots in a raster grid have a common center, equal spacing and symmetrical layout. The visual impression of the image is created by the small sets of raster, which can be dense or sparse depending on their size. This is due to the inability of the human eye to see the dots from a distance, so that it only discerns the tonal image they create..

There are two types of raster, AM and FM. AMs, Amplitude Modulation, are dots in rows, with a constant spacing but fluctuating in diameter. Correspondingly, Frequency Modulation FMs are dots at random, with different distances between them, depending on how dark or bright our image points are and a fixed dimension.

The raster may have different shapes. The best known raster is the round one, but there is also the elliptical and the square raster. These shapes can be used at the same time to avoid creating a moire, an error that occurs when the color rasters are not correctly positioned over each other during the editing process.