Daguerreotype [ note 1 ] was the first publicly available photographic process, widely used during the s and s. Invented by Louis Daguerre and introduced worldwide in , [ 2 ] [ 3 ] [ 4 ] the daguerreotype was almost completely superseded by with new, less expensive processes, such as ambrotype collodion process , that yield more readily viewable images. There has been a revival of the daguerreotype since the late 20th century by a small number of photographers interested in making artistic use of early photographic processes.
To make the image, a daguerreotypist polished a sheet of silver-plated copper to a mirror finish; treated it with fumes that made its surface light-sensitive; exposed it in a camera for as long as was judged to be necessary, which could be as little as a few seconds for brightly sunlit subjects or much longer with less intense lighting; made the resulting latent image on it visible by fuming it with mercury vapor; removed its sensitivity to light by liquid chemical treatment; rinsed and dried it; and then sealed the easily marred result behind glass in a protective enclosure.
The image is on a mirror-like silver surface and will appear either positive or negative , depending on the angle at which it is viewed, how it is lit and whether a light or dark background is being reflected in the metal. The darkest areas of the image are simply bare silver; lighter areas have a microscopically fine light-scattering texture. The surface is very delicate, and even the lightest wiping can permanently scuff it. Some tarnish around the edges is normal. Several types of antique photographs, most often ambrotypes and tintypes , but sometimes even old prints on paper, are commonly misidentified as daguerreotypes, especially if they are in the small, ornamented cases in which daguerreotypes made in the US and the UK were usually housed.
The name "daguerreotype" correctly refers only to one very specific image type and medium, the product of a process that was in wide use only from the early s to the late s. Since the Renaissance era, artists and inventors had searched for a mechanical method of capturing visual scenes. A camera obscura optically reduces a real scene in three-dimensional space to a flat rendition in two dimensions. In the early 17th century, the Italian physician and chemist Angelo Sala wrote that powdered silver nitrate was blackened by the sun, but did not find any practical application of the phenomenon.
The first reliably documented attempt to capture the image formed in a camera obscura was made by Thomas Wedgwood as early as the s, but according to an account of his work by Sir Humphry Davy :. The images formed by means of a camera obscura have been found too faint to produce, in any moderate time, an effect upon the nitrate of silver. To copy these images was the first object of Mr.
