halftone process

In printing, a technique of breaking up an image into a series of dots to permit reproduction of the full tone range of a photograph or artwork.

It is traditionally done by placing a glass screen printed with a tight grid of lines over the plate being exposed. The grid breaks up the image into hundreds of tiny dots, each of which is read by the camera as either black or white

or, in the case of colour art, as either a single printing colour or white. The resulting image, called a halftone, is then rephotographed for printing. Screens are made with a varying number of lines per inch, depending on the application; for newspapers the range is about 80–120, whereas glossy magazines usually require 133–175 lines per inch.

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▪ printing

      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.

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