First successful form of photography .
It is named for Nicéphore Niepce . They found that if a copper plate coated with silver iodide was exposed to light in a {{link=camera">camera , then fumed with mercury vapour, and fixed (made permanent) by a solution of common salt, a permanent image would be formed. The first daguerreotype image was produced in 1837, by which time Niepce had died, so the process was named for Daguerre. Many daguerreotypes, especially portraits, were made in the mid 19th century; the technique was gradually replaced by the wet collodion process, introduced in 1851.