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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of printing | 16/16 | https://en.wikipedia.org/wiki/History_of_printing | reference | science, encyclopedia | 2026-05-05T04:00:12.806227+00:00 | kb-cron |
Halftone is the reprographic technique that simulates ones it is 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.
=== Xerography ===
Xerography (or electrophotography) is a photocopying technique developed by Chester Carlson in 1938 and patented on October 6, 1942. He received U.S. patent 2,297,691 for his invention. The name xerography came from the Greek radicals xeros (dry) and graphos (writing), because there are no liquid chemicals involved in the process, unlike earlier reproduction techniques like cyanotype. In 1938 Bulgarian physicist Georgi Nadjakov found that when placed into electric field and exposed to light, some dielectrics acquire permanent electric polarization in the exposed areas. That polarization persists in the dark and is destroyed in light. Chester Carlson, the inventor of photocopying, was originally a patent attorney and part-time researcher and inventor. His job at the patent office in New York City required him to make a large number of copies of important papers. Carlson, who was arthritic, found this a painful and tedious process. This prompted him to conduct experiments with photoconductivity. Carlson experimented with "electrophotography" in his kitchen and in 1938, applied for a patent for the process. He made the first "photocopy" using a zinc plate covered with sulfur. The words "10-22-38 Astoria" were written on a microscope slide, which was placed on top of more sulfur and under a bright light. After the slide was removed, a mirror image of the words remained. Carlson tried to sell his invention to some companies, but because the process was still underdeveloped he failed. At the time multiple copies were made using carbon paper or duplicating machines and people did not feel the need for an electronic machine. Between 1939 and 1944, Carlson was turned down by over 20 companies, including IBM and General Electric, neither of which believed there was a significant market for copiers.
== See also ==
== References ==
== Bibliography == Barker, Nicolas. "Printing and the Mind of Man." 2013. The Book Collector 62 (3) Autumn: 371–83. Barrett, Timothy Hugh (2008), The Woman Who Discovered Printing, Great Britain: Yale University Press, ISBN 978-0-300-12728-7 (alk. paper) Berry, W. Turner; Poole, H. Edmund (1966), Annals of Printing: A Chronological Encyclopaedia From the Earliest Times to 1950, Blandford Press Bulliet, R. W. (1987). "Medieval Arabic Ṭarsh: A Forgotten Chapter in the History of Printing". Journal of the American Oriental Society. 107 (3): 427–438. doi:10.2307/603463. JSTOR 603463. Chia, Lucille (2011), Knowledge and Text Production in an Age of Print: China, 900-1400, Brill Condorelli, Marco (2022), Standardising English Spelling: The Role of Printing on Sixteenth and Seventeenth-Century Graphemic Developments, Great Britain: Cambridge University Press, doi:10.1017/9781009099912, ISBN 978-1-00-909991-2, S2CID 247900493 Library of Congress. (1939). Colonial Printing in Mexico: Catalog of an exhibition held at the Library of Congress in 1939 commemorating the four hundredth anniversary of printing in the New World. U.S. G.P.O. McDermott, Joseph P. (2006), A Social History of the Chinese Book McMurtrie, Douglas C. (1962), THE BOOK: The Story of Printing & Bookmaking, Oxford University Press, seventh edition Moxon, Joseph. Mechanick Exercises on the Whole Art of Printing (1683–4), ed. Herbert Davis and Harry Carter (London:Oxford University Press, 1958). Qi, Han (2015), Lecture 2 Printing, Springer Tsien, Tsuen-Hsuin (1985), Paper and Printing, Science and Civilization in China, vol. 5, Cambridge University Press, ISBN 0-521-08690-6 Twitchett, Denis (1998b), The Cambridge History of China Volume 8 The Ming Dynasty, 1368–1644, Part 2, Cambridge University Press Wilkinson, Endymion (2012), Chinese History: A New Manual, Harvard University Asia Center for the Harvard-Yenching Institute