The additive reproduction process usually uses yellow (Y), blue (C) and purple red (M) as basis to produce the other colors. This synthesis is seen when illuminating colored print with white light. The light falls on the colored area and part of it is absorbed by the colored layer and the other part (the one that is reflected) is registered by the eye of the observer.
The color modification in the additive synthesis is due to the change in the correlation and intensity of the basic reflections, while in the combination method the color modification depends on the density of the layers and the color concentration in them. This is the reason to use the term primary colors together with the terms additive and subtractive color coordinates.The third variety of color synthesis is the so called autotype or raster synthesis. This type is based on the combination of small, invisible for the human eye raster elements with various colors. This synthesis can be one, two, three, four-colored and so on, but the principle is the same. For example let’s look at the three colored autotype synthesis – you must put consecutively three colors on a piece of paper (first cyan, then magenta and yellow). Let’s suppose that we print yellow first. Afterwards when we print magenta the white spaces, left after the yellow print, are already filled, but raster elements also appear from the magenta and combined with the yellow we see two colors. In this case the new color is red – coming from the combination of yellow and magenta. After we print the third color – cyan, new two-colored blue and green spaces appear, but there are also three-colored black spaces.
The autotype synthesis finds its basic application in polygraphy. It combines elements from the additive as well as from the subtractive synthesis. Here colored halftone images are created from raster elements with various colors, different sizes and shapes.
