Alphonse Louis Poitevin

(b Conflans-sur-Anille, Sarthe, ?1819; d Conflans-sur-Anille, 4 March 1882). French photographer, engineer and chemist. He began photographic research in 1842 while studying civil engineering at the Ecole Centrale, Paris, and continued during his career as a chemical engineer in government service. He is regarded as the practical founder of the carbon print process, photolithography and the collotype process. His inventions included methods for photochemical engraving and daguerreotype plates (c. 1842-8), gelatin negatives on glass (c. 1850-51), photolithography (1855), photoelectrotyping ('h?lio-plastie', patented 1855) and direct paper positives and negatives in colour (results published 1859). From c. 1849 and during the 1850s he photographed his fellow workers at saltworks in the French Jura and landscapes near his family home, using a paper negative process (see Jammes and Parry Janis, pl. xiii).

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Poitevin, Louis Alphonse (1819-82), French photographer and photographic inventor. He encountered photography while studying engineering at the École Centrale des Arts et Manufactures in Paris (1838-43), and subsequently produced both daguerreotypes and calotypes. As early as 1842, however, he embarked on research relating to the dual problem hindering the dissemination of photographic images: the instability of the silver salts that composed the photographic image, and the slowness and cost of reproducing it. A meeting with Edmond Becquerel (1820-91), who encouraged him and publicized his early work, was decisive. In 1855 Poitevin perfected the process of photolithography by coating a lithographic stone with albumen (or, alternatively, gelatin) sensitized with potassium dichromate. In 1857, after attempting unsuccessfully to exploit the process himself, Poitevin sold the rights to the lithographic printer Lemercier. In 1860 Poitevin invented a process of permanent printing using carbon or coloured powder, and sold 30 licences worldwide. He also worked with Becquerel on colour photography, but without decisive results. His efforts were rewarded by two prizes offered by the duc de Luynes in 1862 and 1867, and by a special award at the 1878 Paris Exhibition. The importance of his discoveries has led to him being called ‘photography's fourth inventor’.

— Sylvie Aubenas

Bibliography

• Alphonse Poitevin: collections du Musée Niépce (1987).
• Aubenas, S., D'encre et de charbon: le concours photographique du duc de Luynes, 1856-1867 (1994)