Origin of The Process
In 1851, Frederick Scott Archer introduced a wet plate process, sometimes referred to as the collodion process after the carrier material used. The process is simple: a bromide, iodide, or chloride is dissolved in collodion (a solution of pyroxylin in alcohol and ether). This mixture is poured on a cleaned glass plate, which is allowed to sit until the coating gels but is still moist. The plate is then placed in a silver nitrate solution, which converts the iodide, bromide, or chloride to silver iodide, bromide or chloride. Once the reaction is complete, the plate is removed from the silver nitrate solution and exposed in a camera while still wet. The plate loses sensitivity as it dries, requiring it to be coated and sensitized immediately before use. It must also be developed while still moist, using a solution of iron sulfate, acetic acid and alcohol in water.
The sensitivity of silver halides to light is the underlying principle behind most types of 19th century photographic processes (Daguerreotypes, Ambrotypes, Calotypes that use paper negatives, and wet and dry plates) as well as modern 20th century photographic film processes.
Read more about this topic: Collodion Process
Famous quotes containing the words origin of the, origin of, origin and/or process:
“In the woods in a winter afternoon one will see as readily the origin of the stained glass window, with which Gothic cathedrals are adorned, in the colors of the western sky seen through the bare and crossing branches of the forest.”
—Ralph Waldo Emerson (1803–1882)
“Someone had literally run to earth
In an old cellar hole in a byroad
The origin of all the family there.
Thence they were sprung, so numerous a tribe
That now not all the houses left in town
Made shift to shelter them without the help
Of here and there a tent in grove and orchard.”
—Robert Frost (1874–1963)
“Though I do not believe that a plant will spring up where no seed has been, I have great faith in a seed,—a, to me, equally mysterious origin for it.”
—Henry David Thoreau (1817–1862)
“Every modern male has, lying at the bottom of his psyche, a large, primitive being covered with hair down to his feet. Making contact with this Wild Man is the step the Eighties male or the Nineties male has yet to take. That bucketing-out process has yet to begin in our contemporary culture.”
—Robert Bly (b. 1926)