Section 4 | Page 6

The coarseness of the grid, or screen ruling, determines the distance from the center of one dot to another. Newer digital screening methods produce very small, similar- sized dots randomly placed, not on a fixed grid. In these screened images, the number of small dots in a given area changes proportionally to the tonal value of the original image. Regardless of the screening method, a continuous-tone image must be converted into small dots to be reproducible on press.

These illustrations show dots produced by two types of screening methods: conventional halftone screening and stochastic screening. Conventional halftone screening methods produce dots of different sizes in a fixed grid pattern. Stochastic screening produces very small same-sized dots spaced randomly apart. Some stochastic systems randomly place variably sized dots.