Two positives are made from the Continuous tone copy, one through a halftone screen or a special contact screen and the other without a screen.
Stochastic screening or FM screening is a halftone process based on pseudo-random distribution of halftone dots, using frequency modulation (FM) to change the density of dots according to the gray level desired.
Likewise, when Hermann Wilhelm Vogel's advances in color photography became known, Kurtz arranged to purchase the American rights to the "three-color process" from Vogel and was able to devise a way to apply it to halftone printing.