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pain | paper | plastic | plugs | power | protective | rectangular | ritual | round | sound | souvenir | spiritual | style | text-based | time | tool | touch | uniform | value | visual | warm | wood
Narrative: These glass negatives were found. The collodion process is an early photographic process, invented by Frederick Scott Archer. 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 plates—glass plates with a photographic emulsion of silver halides suspended in gelatin. The dry gelatin emulsion was not only more convenient but could be made much more sensitive, greatly reducing exposure times. bromide and iodide salts dissolved in collodion, which is a solution of pyroxylin in alcohol and ether. This mixture poured onto a cleaned glass plate, and allowed to sit for a few seconds. The plate then placed into a solution of silver nitrate in water, which would convert the iodide, bromide salts to silver iodide, bromide, respectively. Once this reaction complete, the plate removed from the silver nitrate solution, and exposed in a camera while still wet. It developed with a solution of iron sulfate, acetic acid and alcohol in water. Then plate fixed with sodium thiosulfate. After that the plate washed with tap water. Finally it protected with gum sandarac varnish. Glass is made by melting together several minerals at very high temperatures. Silica in the form of sand is the main ingredient and this is combined with soda ash and limestone and melted in a furnace at temperatures of 1700°C.