gelatin silver photograph
(also silver gelatin photograph), n. ~ A photographic print, negative, or transparency with an image formed from metallic silver in a gelatin emulsion on a base of paper, plastic film, glass, or other material.
The metallic silver is formed from silver halides (silver chloride, silver bromide, and silver iodide). Different processes use different combinations of silver halides. A gelatin silver photograph usually has a neutral black-and-white tone unless it is chemically altered (toning) or color is added after it is developed. Gelatin silver became the dominant photographic process after the 1890s and remains the dominant black-and-white photographic process.