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Silver nitrate is an inorganic compound with chemical formula AgNO 3. It is a versatile precursor to many other silver compounds, such as those used in photography.
However, there seem to be no historical records of any ideas even remotely resembling photography before 1700, despite early knowledge of light-sensitive materials and the camera obscura. [15] In 1614 Angelo Sala noted that [16] sunlight will turn powdered silver nitrate black, and that paper wrapped around silver nitrate for a year will turn ...
Schulze is best known for his discovery that the darkening in sunlight of various substances mixed with silver nitrate is due to the light, not the heat as other experimenters believed, and for using the phenomenon to temporarily capture shadows. [1] Schulze's experiments with silver nitrate were undertaken in about 1717. [2]
The light-sensitive silver halide in calotype paper was silver iodide, created by the reaction of silver nitrate with potassium iodide. First, "iodised paper" was made by brushing one side of a sheet of high-quality writing paper with a solution of silver nitrate, drying it, dipping it in a solution of potassium iodide, then drying it again.
1614 – In Septem planetarum terrestrium spagirica recensio, [2] Angelo Sala reported that "Si lapidem lunearem pulveratum ad solem exponas instar atramenti niggerimus" (When you expose powdered silver nitrate to sunlight, it turns black as ink), and also its effect on paper; silver nitrate wrapped in paper for a year turned black.
Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glass, films (of cellulose nitrate, cellulose acetate or polyester), paper, or fabric.
Shortly later, silver iodide and silver bromide emulsions were produced. These proved to be significantly faster, and the image could be brought out by development. The emulsions also had the advantage that they could be washed. In the wet collodion process, silver nitrate reacted with a halide salt; potassium iodide, for example.
silver nitrate with a binder of albumen - derived from egg white, and widely used in printing-out paper in the nineteenth century - had been coated on glass; but these proved to be too insensitive for camera use. Gelatin had also been suggested by photo-theorist and colour pioneer Thomas Sutton, and the substance would also have been known to ...