Louis Jacques Mande Daguerre
Daguerreotype is a photograph made by the first practical process of photography. The process, invented by Louis Daguerre in 1839, was based on the light sensitivity of silver iodide. It consisted of exposing a silver-surfaced brass plate to iodine vapor, which, interacting with the silver, formed a thin layer of silver iodide. After exposure in the camera, the latent image on the plate was developed by treating the silvered surface with mercury vapor. The mercury combined with the exposed silver iodide to form an image consisting of a mercury-silver amalgam. The unexposed silver iodide was then removed by immersing the plate in a solution of sodium thiosulfate. After rinsing in water, the plate was dried and mounted under glass to protect it.
The process, as described by Daguerre in 1839, required an exposure time of from 10 to 15 minutes in full sunlight. The following year the time of exposure was greatly reduced by sensitizing the plate with silver iodide and silver bromide. In 1841 a new portrait lens reduced the exposure time still further.
Portrait studios were opened in London, Philadelphia, New York, and most other large cities early in 1840. In 1853 there were more than 80 daguerreotype studios in New York City.
Louis Jacques Mande Daguerre (1789-1851), French inventor of the first practical process of photography, the daguerreotype. He was also an artist, and the inventor of the diorama (1822).
Daguerre was born in Cormeilles-en-Parisis, Seine-et-Oise, France, on Nov. 18, 1789. Originally a theatrical scene painter, in 1822 he established the Diorama, a theatrical spectacle that required large panoramic paintings. Accurate details and perspective were often attained in the paintings by making the basic sketches with the aid of a camera obscura.
Daguerre decided to try to make the camera obscura images permanent with a light-sensitive substance. However, there is no record of his earliest experiments. He had accomplished little until 1829, when he learned that Joseph Nicephore Niepce was engaged on the same problem and with some success.
The inventors were brought together by the optician Charles Chevalier, in 1826, and a meeting was arranged, and the two agreed to a partnership. They signed in 1829 an agreement on co-operation "for the further improvement of the invention of Niepce which was perfected by Daguerre". Daguerre discarded as impractical the asphalt process on which Niepce had spent several years. Niepce died in 1833.
The decisive step in the invention of the daguerreotype was Daguerre's discovery (1835) of the possibility of developing with mercury vapour the iodized silver plates the partners had been using.
Daguerre returned to Niepce's earlier work with silver salts and found that silver iodide was more sensitive to light than silver nitrate, but more importantly he discovered the latent image. He found that mercury would develop an image on a silver plate sensitized with silver iodide after an exposure of 10 to 15 minutes; Niepce had required hours to obtain an image. In the same year Daguerre found that common salt would make the image permanent; Niepce had been unable to fix his images. The final step was to fix the picture with sodium chloride (1837).
Early in 1839 the Diorama burned. Daguerre and Niepce's son Isidore, failing to sell the daguerreotype process to pay debts, accepted pensions for lire from the government in exchange for the invention. The first report of the discovery was made by the French physicist Arago, on 7th January, 1839, to the French Academy of Sciences. The publication of the process followed on 19th August, 1839. A printed handbook was published at the same time. The process was bought by the French Government and given "free to the world" on 19th August, 1839, but had been patented in England, Wales and the Colonies five days earlier. The coming of the daguerreotype aroused vivid interest over the whole of the civilized world, and for some years the process was popular. Its one grave defect, that it produced one original only, was the cause of its gradual replacement by negative-positive processes whereby copies could be produced.
By the end of the year daguerreotypes were being made all over the world. Daguerre took no part in the improvements in the process that followed rapidly. He retired to a country home in Brysur-Marne near Paris where he died on July 10, 1851.