Stochastic screening, also known as frequency modulation (FM), is a relatively new method of reproducing halftone screens.
Traditional halftone screens – also called amplitude modification (AM) – simply adjust the size of the dots to reproduce tonal variations in images. Larger dots produce darker tones, whilst smaller dots reproduces the lighter areas of an image.
Stochastic screening aims to achieve a higher quality reproduction of graphic images by using complex mathematical algorithms to modify the number of halftone dots.
By varying their position and clustering of halftone dots, stochastic screening can achieve a smoother tonal reproduction and a higher quality printed reproduction of image detail.
Another advantage of using a stochastic screening method is that it can have a dramatic effect on reducing the potential for moire patterns to appear.
Images are converted digitally into screens made up of very small dots which are equal in size, but of variable spacing.
The variable dot pattern eliminates many of the moirÃ© patterns and allows for more than four colors to be used to represent an image.
This is the primary aspect of high-fidelity printing.