Stochastic vs. Conventional Printing
Computer-To-Plate technology has allowed more printers to utilize a different technique for printing halftones known as Frequency Modulation (FM) screening, or stochastic printing. However, conventional screening, or Amplitude Modulation (AM), is certainly not obsolete, especially when higher line screens of 175 to 200 are used in halftone and four color process printing.
The best way to define stochastic printing is to compare it to conventional printing.
In conventional printing, images are printed using grid-like screens that separate the image into evenly space dots that are larger in size in the darker areas and smaller in size in the light areas. In four color process printing, separate screens are used to reproduce each of the four colors, black, cyan, magenta and yellow.
In stochastic printing, images are printed by dots spread randomly throughout the image area. The dots are not equally spaced and aligned in a row or grid and they vary according to the tonal value to be reproduced. The lighter areas have few dots, the darker areas have more dots.
There are significant differences, advantages and disadvantages of both stochastic and conventional screening. Printing with stochastic screening offers the advantages of more detail, less ink on the sheet, no moiré pattern, increase tonal values, crisper fine lines and small type and cleaner reverses. Conventional screens have the advantages of greater latitude of changing color density on press, more forgiving halftone reproduction, better printing of large amounts of ink on paper and better production of one and two color printing.
To read more about advantages and disadvantages of stochastic printing, check out this article on neenahpaper.com