Regnault, Henri (b Aix-la-Chapelle, 21 July 1810; d Paris, 19 Jan 1878).

Photographer, scientist and physician. He was a self-taught scientist and a member of the Académie des Sciences from 1840. He first approached photography from a scientific viewpoint c. 1845–7, discovering the use of pyrogallic acid as a developing fluid. He was the first president of the Société Française de Photographie, founded in 1854. He also collected photographs by French pioneers (album in Paris, Soc. Fr. Phot.) and worked for the photographic printer Louis-Désiré Blanquart-Evrard.