Daguerreotype, the first practical photographic process, announced at the French Academy of Sciences in Paris on January 7, 1839. A description of the process was not published until August 1839. The process, which was an early milestone in the history of photographic techniques, was a refinement of experiments conducted after 1814 by French inventor Joseph Nicéphore Niépce. Between 1829 and 1833, Niépce collaborated with French artist L. J. M. Daguerre, who continued to experiment with the technique after Niépce’s death in 1833. Daguerre's significant improvements on the Niépce process, especially his use of a salt solution to make the image permanent, served as justification to Daguerre to name the proĆcess after himself.
In 1839 French inventor Louis Jacques Daguerre announced his development of the first photographic process suitable for widespread use. Called the daguerreotype, DaĆguerre’s process involved recording an image on a metal plate coated with special chemicals. Daguerre is shown here in a daguerreotype from 1846.
The daguerreotype was a positive image made on copper plates coated with highly polished silver, sensitized by fumes of iodine. Following exposure in the camera, the latent image was developed in mercury vapor and then made permanent with a solution of common table salt. The result was a finely detailed image with a delicate surface. This had to be protected against abrasion by a glass cover and sealed to prevent tarnishing through contact with air. Initially, Daguerre’s process was not very light sensitive and the time of exposure could be as long as 30 minutes, but exposure times were reduced as a result of improvements developed in Austria, England, and the United States. By the beginning of the 1840s, his invention had come into widespread use; most European capitals and large towns had at least one photographic portrait studio, and traveling photographers visited smaller towns.
One of the main drawbacks of the daguerreotype process was that each image was unique. Another photographic process, the calotype, was invented around the same time as the daguerreotype, by British scientist William Henry Fox Talbot. With the calotype process, any number of positive prints could be made from an initial negative image, although these images lacked the clarity of a daguerreotype. Both the daguerreotype and the calotype had become almost obsolete by the mid-1850s because a new process, utilizing a coating known as collodion on a glass negative, combined the daguerreotype’s fine detail with the calotype’s easy reproducibility.
to cite this article:
"Daguerreotype," Microsoft® Encarta® Online Encyclopedia 2004
http://encarta.msn.com © 1997-2004 Microsoft Corporation. All Rights Reserved.
© 1993-2004 Microsoft Corporation. All Rights Reserved.