Alphonse Poitevin

Louis-Alphonse Poitevin, engineer trained at the École Centrale des Arts et Manufactures in Paris (class of 1843), devoted his career to applying chemistry to photographic reproduction. Building on Mungo Ponton's 1839 discovery that potassium dichromate is photosensitive, Poitevin demonstrated in 1855 that this property extends to pigmented colloids — gum arabic, gelatin combined with carbon black — which become insoluble where exposed to light. That same year he filed his foundational patents on the gum bichromate process, the carbon process and photolithography, laying the foundation for the entire family of pigment-based alternative processes — gum bichromate, carbon transfer, bromoil, gumoil — that remained dominant for fine art photographic printing through the 20th century. In 1862 he published the Traité de l'impression photographique sans sels d'argent, a reference manual on pigment processes; he was also awarded the Duc de Luynes Prize for photolithography (exact amount not confirmed across sources). Named Chevalier de la Légion d'honneur on 24 January 1863, he was further distinguished at the Paris Universal Exhibition of 1878. After his industrial career in the salt works of Dieuze, Montmorot and Gouhenans and as manager of the Ahun-les-Mines and Folembray glassworks, Poitevin retired to Conflans-sur-Anille (Sarthe), where he served as mayor from 1871 to 1878. His original plates, patents, and reference albums are held at the Bibliothèque nationale de France (Gallica), the Musée d'Orsay and the Société française de photographie archives. Poitevin's patrimonial rights lapsed in France in 1953. At Maison Picturale, his historical reproductions and scientific plates can be reinterpreted as contemporary gum bichromate prints — a tribute to the inventor of the very process we now use without dichromate, thanks to Vision Picturale's reformulation.