- Nancy B. Keeler
(b Breteuil-sur-Noye, Oise, Jan 20, 1801; d Nemours, Seine-et-Marne, May 14, 1887).
French photographer and civil servant. His invention in early 1839 of direct positive photography on paper, by using silver chloride and potassium iodide, upon which light acted as a bleach, was totally original. It differed from the daguerreotype of Louis-Jacques-Mandé Daguerre in producing a positive image on paper rather than on a metal plate, and it differed from the invention of William Henry Fox Talbot in that it produced a positive image without the use of a negative (see Photography, §I). Bayard’s images were sharper than Talbot’s, but because of their paper support they still lacked the fine detail of the daguerreotype. Unable to secure the influential patronage of the scientist and politician François Arago, who was backing Daguerre, Bayard undertook to promote his own invention, with remarkable success. In July 1839—one month before the daguerreotype process was publicly divulged—Bayard showed his photographs in a benefit art exhibition in Paris and gained favourable reviews. This was the first public ...