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Uranyl nitrate is a yellow poisonous crystal made by dissolving uranic oxide in nitric acid. It is soluble in water, alcohol, and ether. First suggested by C. J. Burnett in 1855, a uranyl nitrate printing process was patented by Niépce de St. Victor in 1858. The paper was floated on a uranyl nitrate solution and dried in the dark. The paper was exposed under a negative in the sun until a faint image appeared. The image was developed to completion by floating the paper on a solution of silver nitrate or gold chloride followed by washing. A process patented in 1864 by Jacob Wothly called for adding uranyl nitrate and silver to collodion, which was then applied to paper. The Wothlytype was a printing-out process.
Uranyl nitrate was used in printing-out emulsions and with potassium ferricyanide for toning prints and intensifying negatives. It was also used with silver nitrate for making uranium/ silver gaslight papers.

Poison by inhalation. Moderately toxic by ingestion. Human mutation data reported. A corrosive irritant to skin, eyes, and mucous membranes. A radioactive material. A powerful explosive and oxibzer. Incompatible with cellulose. Ether solutions in sunlight may explode. When heated to decomposition it emits toxic fumes of NOx. See also URANYL NITRATE HEXAHYDRATE and URANIUM.