24...Halftoning

Halftone is the reprographic technique that simulates continuous tone imagery through the use of equally spaced dots of varying size. 'Halftone' can also be used to refer specifically to the image that is produced by this process. The idea of halftone printing originates from William Fox Talbot. In the early 1850s he suggested using "photographic screens or veils" in connection with a photographic intaglio process.
Several different kinds of screens were proposed during the following decades, but the first half-tone photo-engraving process was invented by Canadians George-Édouard Desbarats and William Leggo Jr. On October 30, 1869, Desbarats published the Canadian Illustrated News which became the world’s first periodical to successfully employ this photo-mechanical technique; featuring a full page half-tone image of His Royal Highness Prince Arthur, from a photograph by Notman. Ambitious to exploit a much larger circulation, Debarats and Leggo went to New York and launched the New York Daily Graphic in March 1873, which became the world’s first illustrated daily.
The first truly successful commercial method was patented by Frederic Ives of Philadelphia in 1881. But although he found a way of breaking up the image into dots of varying sizes he did not make use of a ===screen===. In 1882 the German George Meisenbach patented a halftone process in England. His invention was based on the previous ideas of Berchtold and Swan. He used single lined screens which were turned during exposure to produce cross-lined effects. He was the first to achieve any commercial success with relief halftones.