halftone process, in printing, a technique of breaking up an image into a series of dots so as to reproduce the full tone range of a photograph or tone art work. Breaking up is usually done by a screen inserted over the plate being exposed. The screens are made with a varying number of lines per inch, depending on the application; for newspapers, the range is 50 to 85, and for magazines, 100 to 120. The highest quality reproduction requires 120 to 150 lines per inch.