Dry plate

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Dry plate, also known as gelatine process, is the first economical successful durable photographic medium. It was discovered by Richard L. Maddox in 1871 and by 1879 it was so well introduced that the first dry plate factory had been established.

1 Historical considerations
2 The development
3 The drawbacks
4 Bibliography
5 External Links

[edit] 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 minutes of preparing and secondarily because it was very little sensitive.

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 all 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. Locally these plates had a limited success though.

[edit] The development

Gelatine emulsions as proposed by Maddox were very sensitive to touch and mechanical friction and not much less sensible than collodion emulsions to light.

Charles Bennet discovers a method of hardening the emulsion, making it more resistant to friction in 1873.

Charles Bennet discovers that by cooking (prolonged heating) the gelatine emulsion the sensitivity could be greatly increased in 1878.

George Eastman develops a machine to coat plate, reducing the cost of photography in 1879.

[edit] The drawbacks

It is always said, from interested party, that the main reasons for the failure of the dry plate to be accepted universally was the conservative attitude of some photographers. The truth is that, besides being more sensible, the early gelatine emulsions were grainier than collodion emulsions, and they were highly insensible to green light.