Daguerreotype << duh GEHR uh typ >> was the first practical, popular method of photography. It was named for Louis J. M. Daguerre, a French stage designer and painter who perfected the process in 1837. The word daguerreotype also refers to photographs produced by this process.
Daguerre’s process involved treating a thin sheet of silver-plated copper with fumes from crystals of iodine to make the silver plating sensitive to light. The sheet was then placed inside a camera and exposed to light through the camera lens for 5 to 40 minutes. After the sheet was removed from the camera, it was developed by vapors from heated mercury. The mercury combined with the silver at the points where it had been affected by light, and formed a highly detailed image. The image was then fixed (made permanent) by treating the sheet with sodium thiosulfate.
Daguerre first published a description of his process in 1839. The process was soon improved by other inventors. By 1841, for example, the exposure time for the photographs had been reduced to less than a minute.
Daguerreotype portraits were tremendously popular during the 1840’s and 1850’s, especially in the United States. The daguerreotype was eventually replaced by other processes. People now collect daguerreotypes of particular beauty or unusual subject matter.
See also Daguerre, Louis J. M.; Photography (History).
