Louis Jacques Mande Daguerre, French photography pioneer, 19th century.
© Science Museum / Science & Society Picture Library
Photograph of a monument in Bry-sur-Marne of Louis Jacques Mande Daguerre (1787-1851). Daguerre collaborated on his original photography research with Joseph Niepce (1765-1833). The daguerreotype proces, the first widespread and practical photographic proces, was announced to the French Academy of Sciences on 9 January 1839. The proces comprises a copper plate with a highly polished silver surface sensitized by iodine fumes, exposed in a camera, and developed by fuming over warmed mercury, producing a reversed and unique image