224th Birthday of Louis Daguerre inventor of photography
Louis-Jacques-Mandé Daguerre (November 18, 1787 – July 10, 1851) was a French artist and physicist, recognized for his invention of the daguerreotype process of photography. Daguerre’s name is one of the 72 names inscribed on the Eiffel tower.
Daguerre announced the latest perfection of the Daguerreotype, after years of experimentation, in 1839, with theFrench Academy of Sciences announcing the process on January 7 of that year. The French Government acquired Daguerre’s patent, and, on August 19, 1839, the French Government announced the invention was a gift “Free to the World.”
The daguerreotype was the first commercially successful photographic process. The image is a direct positive made in the camera on a silvered copper plate. The surface of a daguerreotype is like a mirror, with the image made directly on the silvered surface; it is very fragile and can be rubbed off with a finger, and the finished plate has to be angled so as to reflect some dark surface in order to view the image properly. Depending on the angle viewed, and the color of the surface reflected into it, the image can change from a positive to a negative.
The very first daguerreotypes used Chevalier lenses that were “slow”, and the light sensitive material was silver iodide made by fuming the plate with iodine vapour. After that Petzval lenses were introduced, with lenses of a larger diameter and the plate was sensitized with iodine and bromine forming light sensitive crystals of silver iodide and silver bromide, the exposures were reduced so that portraits could be taken.
Louis Daguerre together with Joseph Nicéphore Niépce developed the process.
Although daguerreotypes are unique images, they could be copied by redaguerreotyping the original
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