Stochastic Screening is not a print process, but a pre-press operation prior to litho printing. An example of stochastic screening is Crystal Raster, a trade name belonging to Agfa. The process is also called FM (Frequency Modulated) Screening.
Conventional screening produces half tone images by printing a series of regularly spaced dots, the smaller the dot, the paler the tone and, conversely, the larger the dot, the darker the tone. These dots are all equally spaced, the actual spacing determines the screen resolution (i.e. 133 dots per inch). It is the varying size of dot that varies the change of colour.
Stochastic screening takes a different approach, where the dots are all the same size, but randomly positioned. To produce a light tone, the dots are far apart. Conversely, to create a heavy tone, the dots are printed close together. The dots are all equally sized and it is the varying distribution (or frequency) that gives the varying tone. New applications may also introduce dots of varying size and varying distribution. The dots that are printed are very much smaller than the conventional half tone dot.
The theory of stochastic screening is not new, but only now has there been sufficient computer power to generate the random distribution at viable speeds.
A major benefit of stochastic screening is the elimination of moiré (interference patterns). Conventional screens for four colour printing are set at varying angles to reduce this, there is however, a limit to the number of positions that can be set before moiré occurs again. As the moiré is produced by the regular dot pattern, stochastic screening does not suffer from it (due to the random dot position rather than a regular one) and so, more colours can be printed without moiré occurring. This allows for additional colours to be added for hi-fidelity colour reproduction without the above problems.
It is said that stochastic screening can reproduce finer detail and can be used from newsprint to high quality art paper. It should therefore, be suitable for most products, but the benefits of such screening will depend very much on what is being printed.