Louis Jacques Mandé Daguerre (1787-1851), a French painter and stage designer, invented the daguerreotype, the first practical and commercially successful photographic process.
Louis Daguerre was born on Nov. 18, 1787, at Cormeilles-en-Parisis. Abandoning his architectural training in 1804, he turned to scene painting and became a pupil of I. E. M. Degotti at the Paris Opéra. In 1822 Daguerre and Charles Bouton developed the diorama, a large-scale peep show in which a painting on a large translucent screen was seemingly animated by the skillful play of light on each side. Daguerre made dioramas for 17 years.
Daguerre used the camera obscura to make sketches for his stage designs and, like so many others, wished to avoid the tedious tracing and fix the image chemically. After several unsuccessful efforts he learned in 1826 that J. N. Niépce was working toward the same end and had made some progress. A cautious correspondence followed, in which Niépce revealed his heliograph process, and in 1829 Daguerre and Niépce formed a partnership to develop the method.
Heliography depended on the hardening action of sunlight on bitumen and the subsequent dissolution of the soft shadow parts of the image. Using this method on a glass plate, Niépce had obtained and fixed a photograph from the camera obscura in 1826. But his aspirations went beyond a visible image to a photoengraved plate from which he could pull prints. This goal led to his using bitumen on silver-coated copperplates and then iodizing the silver revealed after dissolving the unexposed bitumen. The removal of the hardened bitumen produced a silver-silver iodide image. But Niépce went no further.
Building on his partner's foundation, Daguerre discovered the light sensitivity of silver iodide in 1831 but was unable to obtain a visible image. His discovery in 1835 that the latent image present on a silver iodide plate exposed for so short a time as 20 minutes could be developed with mercury vapor marked a major advance. Fixing was achieved in 1837, when he removed the unreduced silver iodide with a solution of common salt. Having improved Niépce's process beyond recognition, Daguerre felt justified in calling it the daguerreotype. He ceded the process to the French government. He revealed his discovery on Aug. 19, 1839.
Daguerre retired to Bry-sur-Marne in 1840 and died there on July 10, 1851. He had little more to do with the daguerreotype, leaving its improvement to others. It was perhaps the invention which most caught popular fancy in the mid-19th century, but it proved to be a blind alley in the development of modern photography.
Further Reading on Louis Jacques Mandé Daguerre
Daguerre's life is fully documented in Helmut and Alison Gernsheim, L. J. M. Daguerre: The History of the Diorama and the Daguerreotype (1956). Their The History of Photography (1955) is an excellent overall discussion of photography.