1841: THE CALOTYPE PROCESS
Using salted paper sensitized with silver nitrate or silver chloride, William Henry Fox Talbot (1800–1877) had made contact prints of plant specimens and had taken tiny negative views of windows with small “mousetrap” cameras. He had moved on to other research but immediately returned to his photogenic drawings after learning about the daguerreotype. With help from his friend, the eminent English astronomer John Herschel (1792–1871), who devised the best chemical mixture to fix the images (and also coined the term photography), Talbot improved his techniques. His calotype or talbo-type process, introduced in 1841, employed silver iodide and other chemicals to form a negative image on paper, which could then be used to produce multiple positive contact prints.
"Photography and Talbotype." The Daguerreian Journal, vol. I, no. 2, 1850
"Mr. Fox Talbot's Patents in England." The Photographic Art Journal, vol. 1, no. 5, 1851