A: Paris, Île-de-France, France
On January 7, 1839 members of the Académie des Sciences first viewed examples of Daguerréotypes invented by the painter and printmaker, Louis-Jacques Daguerre.
On July 3, 1839 French mathematician, physicist, astronomer and politician François Jean Dominique Arago made the first brief scientific announcement and explanation of Daguerre's process to the Chambre des députés. This he repeated to the Académie des sciences on August 19. Arago's report was published in the Comptes rendus IX (1839) 250-67.
Later in 1839 Daguerre published in Paris his first account of the process in a pamphlet called Historique et description des procédés du Daguerréotype et du diorama. Daguerre's method of fixing an image on a metal plate became the first commonly used photographic process. It produced a single positive image on a highly polished silver-plated sheet of copper.