COAT, EXPOSE AND PROCESS BEFORE IT DRIES OUT
The plate had dried before it could be processed and lost sensitivity
|The collodion wet plate required that the photographer dissolve a
nitrated cotton into a mixture of alcohol and ether, plus soluble iodide.
This thick liquid had to be poured onto a spotless, clean glass plate,
then the excess drained off. The Alcohol and ether were allowed to
evaporate. The thin film remaining was then sensitized (in the dark) by
immersion in a solution of silver nitrate. A light-sensitive silver
iodide was then formed. While still damp the plate had to be exposed
immediately. It also had to be developed by pouring on developing
agent (sometimes pyrogollic acid) before the surface dried. If the
plate dried prematurely, you obtained the effect shown above, where
sensitivity was lost. There was no temperature control, the
developing solution yielded an image almost instantly.
The plate was then fixed, washed, carefully dried, and then coated with a top lacquer, as the emulsion was very fragile. Doing this under wartime conditions with limited fresh water, the hot sun beating on the dark light-tight wagon was an amazing accomplishment.
The Ansco advertising photographers, McKinley and Bengston, actually made and exposed wet plates to show how it was done, using cameras and lenses of the era.
IT WAS TERRIBLY HARD TO
Every Detail was recorded in amazing sharpness
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