Photography in the United States
In spring 1839, the daguerreotype was introduced into the United States by an Englishman named D.W. Seager, who took the first photograph of a view of St. Paul’s Church and a corner of the Astor House in Lower Manhattan in New York City. Painter and inventor Samuel Finley Breese Morse had met Louis Daguerre in Paris in the spring of 1839, becoming the first American to see his photographic process and becoming enamored with it as a result. When he returned to the United States later that year, he enthusiastically promoted the daguerreotype while hailing Seager's prototypical image. Morse had painted "The Gallery of the Louvre" in 1833, and the appeal of the medium of the daguerreotype was an obvious one to him: it was a means of making faithful copies of artworks, in addition to anything else that would be still in front of the slow eye of the camera.
Conservation and restoration of photographs
1837: Daguerreotype
The daguerreotype process (named after Louis Jacques Mande Daguerre) produces a unique image, as there is no negative created. After coating a copper plate with light-sensitive silver iodide, the plate is exposed to an image for over 20 minutes and then treated with fumes from heated mercury. The longer the exposure to light, the more mercury fumes are adsorbed by the silver iodide. After the plate is washed with salt water, the image appears, reversed. This was the earliest photographic process to gain popularity in America. It was used until around 1860.