DAY 252

HISTORY OF PHOTOGRAPHY

Collodion Process

MAKE ’EM WHILE IT’S WET

Collodion is a light-sensitive concoction made up of guncotton (cotton specially treated with nitric and sulfuric acids) mixed with alcohol and ether that was originally used to treat the wounds of burn victims. When collodion liquid dries as a result of evaporation, it forms a tough, transparent flexible film. In photographic use, the collodion-on-glass negative process was introduced in 1851 by Frederick Scott Archer and was the process of choice for over 30 years. It came to be known informally as the “wet plate process” because the exposure had to be made and processed before the collodion dried.

Images produced from the collodion-treated plates were virtually grain-free, making the process a considerable improvement over the daguerreotype. The process was difficult because the collodion was extremely sticky and could get dirty or dusty quite easily. Also, because the plates had to be treated just prior to exposure and then processed immediately after, the photographer had to carry a cumbersome mobile darkroom everywhere.

Still, the low-cost and high-quality results outweighed the drawbacks and wet-plate processing was an almost immediate success, remaining the dominant photographic method until the mid 1880s, when the dry-plate process was perfected. —DJG