Daguerreotype
Invented by Louis-Jacques-Mandé Daguerre and introduced worldwide in 1839, daguerreotype was almost completely superseded by 1860 with new, less expensive processes yielding more readily viewable images. In the late 20th century, there was a revival of daguerreotypy by a small number of photographers interested in making artistic use of early photographic processes.
Louis Daguerre
When the first reports of the French Academy of Sciences announcement of Daguerre's invention reached Talbot, with no details about the exact nature of the images or the process itself, he assumed that methods similar to his own must have been used, and promptly wrote an open letter to the Academy claiming priority of invention. Although it soon became apparent that Daguerre's process was very unlike his own, Talbot had been stimulated to resume his long-discontinued photographic experiments. The "developed out" daguerreotype process only required an exposure sufficient to create a very faint or completely invisible latent image which was then chemically developed to full visibility. Talbot's earlier "sensitive paper" (now known as "salted paper") process was a "printed out" process that required prolonged exposure in the camera until the image was fully formed, but his later calotype (also known as talbotype) paper negative process, introduced in 1841, also used latent image development, greatly reducing the exposure needed, and making it competitive with the daguerreotype.