Concentric Screening™ is AM screening in which the round AM dots are divided into thin concentric rings. The purpose of Concentric Screening in offset printing is to achieve the benefits of stochastic screening with the smoothness of AM screening. AM screening (below top) contains dots of equal spacing which vary in size. Stochastic screening contains small spots of equal sizes which are randomly distributed. While the benefits of stochastic are real, they are related to the small spot size, not the random distribution. The small spot size of the stochastic screen limits the ink film thickness on the offset plate. However, the random distribution can cause a grainy appearance. By dividing the AM dot into thin concentric rings, the AM dot has similar ink film limiting characteristics on the offset plate. The result is a dramatic increase in quality, color saturation and press stability- resulting in the ability to print much higher screen rulings.
**Concentric Screening™ information provided by Artwork Systems**