Toronto Stochastic Screening
FM versus EM Screening
The concept of stochastic screening is that dots placed randomly will not cause moiré patterns. FM screening products apply advanced algorithms to determine the optimum placement of dots to appear random, yet not cause visual artifacts.
Conventional halftone screening is called Amplitude Modulation (AM) screening. Amplitude means size; AM screening breaks up an image into dots of varying sizes to simulate the original image. FM screening, on the other hand, keeps the dots the same size and varies the frequency, or number, of dots and the location of those dots to simulate the original image. This illustration shows enlarged simulations of AM and FM screening.