- Dry plate
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Dry plate, also known as gelatin process, is an improved type of photographic plate. It was invented by Dr. Richard L. Maddox in 1871, and by 1879 it was so well introduced that the first dry plate factory had been established. With much of the complex chemistry work centralized into a factory, the new process simplified the work of photographers, allowing them to expand their business.
Contents
Historical considerations
The wet plate was, without question, a successful photographic process, but it had its drawbacks. Primarily there was the fact that a wet plate had to be used within ten minutes of preparing and secondly because of its slow photographic speed. The preparation of wet plates required numerous chemicals, beakers and liquids, all mixed in the dark in a portable tent if the photographer was planning on photographing away from the studio.
From the beginning of the wet plate process there were attempts to make plates durable; most notable are the attempts by Robert Bingham in 1850 and Richard H. Norris 1856. Both these processes lacked economical success, though Norris was slightly more successful, even establishing a factory.
The next notable attempt to make durable plates was by Joseph Sidebotham who used a collodion albumen mixture in 1861.
The lack of success for the above was not that it did not work, or that it was complicated, but because at the time, transportation — especially timely transportation — was complicated; by the time a plate from Birmingham in England reached New York in the USA it could be best used as window pane.
In addition, America had an import tariff in place to protect the national glass making industry. The American Excise Department did not recognize the photographic plates and taxed them strictly as sheets of glass.[citation needed] Locally these plates had a limited success, though.
The development
Gelatin emulsions as proposed by Maddox were very sensitive to touch and mechanical friction and not much more sensitive than collodion emulsions to light.
Charles Bennett discovered a method of hardening the emulsion, making it more resistant to friction in 1873. In 1878, Bennett discovered that by prolonged heating, the sensitivity of the emulsion could be greatly increased.
George Eastman developed a machine to coat plates in 1879 and opened the Eastman Dry Plate Company,[1] reducing the cost of photography. A competitor of Eastman in the development and manufacture of gelatin dry plates was the architectural photographer Albert Levy.[2]
References
- ^ University of Rochester History Dept Eastman Dry Plate
- ^ Photography and the American Scene. A social history (1839-1889) by Robert Taft
Bibliography
A Silver Salted Gelatine Emulsion, Richard L. Maddox, (British Journal of Photography, September 8, 1871)
The ABC of Modern Photography, W.A. Burton, ( Piper & Carter, London 2nd Edition, 1879)
History of Photography, Josef Maria Eder (Dover Publications, Mineola, NY, 1945)
From Dry Plates To Ektachrome Film: A Story of Photographic Research, C.E. Kenneth Mees, (Ziff-Davis Publishing Company, New York, NY, 1961)
External links
Categories:- English inventions
- Photographic processes dating from the 19th century
- Photography stubs
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