Daguerreotype
It is said that Daguerre has found the means to collect, on a plate prepared by him, the image produced by the camera obscura, in such a way that a portrait, a landscape, or any view, projected upon this plate by the ordinary camera obscura, leaves an imprint in light and shade there, and thus presents the most perfect of all drawings ... a preparation put over this image preserves it for an indefinite time ... the physical sciences have perhaps never presented a marvel comparable to this one.
A further clue to fixing the date of invention of the process is that when the Paris correspondent of the London periodical "The Athenaeum" reported the public announcement of the daguerreotype in 1839, he mentioned that the daguerreotypes now being produced were of considerably better quality than the ones he had seen "four years earlier".
Daguerreotype
Although the daguerreotype process is sometimes said to have died out completely in the early 1860s, documentary evidence indicates that some very slight use of it persisted more or less continuously throughout the following 150 years of its supposed extinction. A few first-generation daguerreotypists refused to entirely abandon their old medium when they started making the new, cheaper, easier to view but comparatively drab ambrotypes and tintypes. Historically minded photographers of subsequent generations, often fascinated by daguerreotypes, sometimes experimented with making their own or even revived the process commercially as a "retro" portraiture option for their clients. These eccentric late uses were extremely unusual and surviving examples reliably dated to between the 1860s and the 1960s are now exceedingly rare.