Daguerreotype
Invented by Louis-Jacques-Mandé Daguerre and introduced worldwide in 1839, daguerreotype was almost completely superseded by 1860 with new, less expensive processes yielding more readily viewable images. In the late 20th century, there was a revival of daguerreotypy by a small number of photographers interested in making artistic use of early photographic processes.
Daguerreotype
In the Becquerel variation of the process, published in 1840 but very seldom used in the 19th century, the plate, sensitized by fuming with iodine alone, was developed by overall exposure to sunlight passing through yellow or red glass. The silver iodide in its unexposed condition was insensitive to the red end of the visible spectrum of light and was unaffected, but the latent image created in the camera by the blue, violet and ultraviolet rays color-sensitized each point on the plate proportionally, so that this color-filtered "sunbath" intensified it to full visibility, as if the plate had been exposed in the camera for hours or days to produce a visible image without development.