Dry plate
Encyclopedia
Dry plate, also known as gelatin process, is an improved type of photographic plate
Photographic plate
Photographic plates preceded photographic film as a means of photography. A light-sensitive emulsion of silver salts was applied to a glass plate. This form of photographic material largely faded from the consumer market in the early years of the 20th century, as more convenient and less fragile...

. It was invented by Dr. Richard L. Maddox
Richard Leach Maddox
Richard Leach Maddox was an English photographer and physician who invented lightweight gelatin negative plates for photography in 1871.-Early life:Richard Leach Maddox was born at Bath, England, on August 4, 1816....

 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.

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
Collodion-albumen process
The Collodion-Albumen process is one of the early dry plate processes, invented by Joseph Sidebotham in 1861.The process lacked economical success because the plate was much less sensitive and tended to have harder contrasts than wet plates...

 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
Birmingham
Birmingham is a city and metropolitan borough in the West Midlands of England. It is the most populous British city outside the capital London, with a population of 1,036,900 , and lies at the heart of the West Midlands conurbation, the second most populous urban area in the United Kingdom with a...

 in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 reached New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 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
Customs and Excise
Customs and Excise refers to customs duty and excise duty.In certain countries, the national tax authorities that are responsible for collecting those duties are named Customs and Excise, including:...

 did not recognize the photographic plates and taxed them strictly as sheets of glass. Locally these plates had a limited success, though.

The development

Gelatin
Gelatin
Gelatin is a translucent, colorless, brittle , flavorless solid substance, derived from the collagen inside animals' skin and bones. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing. Substances containing gelatin or functioning in a similar...

 emulsions as proposed by Maddox were very sensitive to touch and mechanical friction
and not much more sensitive than collodion
Collodion
Collodion is a flammable, syrupy solution of pyroxylin in ether and alcohol. There are two basic types; flexible and non-flexible. The flexible type is often used as a surgical dressing or to hold dressings in place. When painted on the skin, collodion dries to form a flexible cellulose film...

 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
George Eastman
George Eastman was an American innovator and entrepreneur who founded the Eastman Kodak Company and invented roll film, helping to bring photography to the mainstream...

 developed a machine to coat plates in 1879 and opened the Eastman Dry Plate Company, reducing the cost of photography. A competitor of Eastman in the development and manufacture of gelatin dry plates was the architectural photographer Albert Levy
Albert Levy (photographer)
Albert Levy is a French photographer active in the 1870s-1890s. He is a pioneer on architectural photography that focused his work in Europe and the United States....

.

External links

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