Collodion-albumen process
Encyclopedia
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 (about 1/4)and tended to have harder contrasts than wet plates
. While the first was acknowledged by Sidebotham, the latter were disputed by him indicating the fact that the 1860 gold medal for the best landscape photography
was made with a Collodion-Albumen plate (Recreative Science, 1861 P 43).
and silver bromide
. These decompose and leave silver
that is oxidized by the developer (Pyrogallic Developing Solution). The excess of silver iodine and silver bromide are stabilized by the fixing bath. The albumen mixture just encloses the Collodion
in a dry environment.
Dry plate
Dry plate, also known as gelatin process, is an improved type of photographic plate. It was invented by Dr. Richard L. Maddox in 1871, and by 1879 it was so well introduced that the first dry plate factory had been established...
, invented by Joseph Sidebotham in 1861.
The process lacked economical success because the plate was much less sensitive (about 1/4)and tended to have harder contrasts than wet plates
Collodion process
The collodion process is an early photographic process. It was introduced in the 1850s and by the end of that decade it had almost entirely replaced the first practical photographic process, the daguerreotype. During the 1880s the collodion process, in turn, was largely replaced by gelatin dry...
. While the first was acknowledged by Sidebotham, the latter were disputed by him indicating the fact that the 1860 gold medal for the best landscape photography
Photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...
was made with a Collodion-Albumen plate (Recreative Science, 1861 P 43).
Why does it work?
There are several compounds unstable to light in this mixture, mainly silver iodineSilver iodide
Silver iodide is a yellow, inorganic, photosensitive iodide of silver used in photography, in medicine as an antiseptic, and in rainmaking for cloud seeding.-Crystal structure:...
and silver bromide
Silver bromide
Silver bromide , a soft, pale-yellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials. AgBr is widely used in photographic films and is believed by some to have been used for making...
. These decompose and leave silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
that is oxidized by the developer (Pyrogallic Developing Solution). The excess of silver iodine and silver bromide are stabilized by the fixing bath. The albumen mixture just encloses the 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...
in a dry environment.
Sources
- The Collodio-Albumen Process of Photography, Joseph Sidebotham (London : Recreative Science Vol II 1861)
- History of Photography, Josef Maria Eder (Dover Publications, Mineola, NY, 1945)