Wet plate photography

DEFINITION

Wet Plate ??? the name given to a process invented by Frederick Scott Archer of England in 1851. Widely used to produce negatives but also employed in a modified form to produce positives. As a negative process, a piece of clear glass is coated with a very thin layer of iodized collodion (made from gun-cotton [nitrocellulose] dissolved in ether and alcohol, mixed with potassium iodide). The coated plate is dipped in a silver solution in the darkroom which makes it light-sensitive. After this, the plate must be immediately exposed in a camera. The exposure needs to be completed before the chemicals on the plate have time to dry out ??? hence the name of the process. After development and fixing, the negative can be printed on any material. Most wet plate negatives, however, were used to make prints on albumen paper (see AskART glossary). Photographers using this process included William Abraham Bell and William Wallace Armstrong. Sources: The American Museum of Photography; AskART biographies