THIS IS HOW PHOTOGRAPHY WAS BORN
The main reason for the "partnership", as far as Daguerre was concerned, might have been connected to his already famous dioramas. Niépce was a printer and his process was based on a faster way to produce printing plates. Daguerre perhaps thought that the process developed by Niépce could help speed up his diorama creation. Daguerre announced the latest perfection of the Daguerreotype, after years of experimentation, in 1839, with the French Academy of Sciences announcing the process on January 7 of that year. Daguerre's patent was acquired by the French Government, and, on August 19, 1839, the French Government announced the invention was a gift "Free to the World." The first permanent photograph was made in 1826 by Joseph Nicéphore Niépce, building on a discovery by Johann Heinrich Schultz (1724): a silver carbonate or silver chloride and chalk mixture darkens under exposure to light. Niépce and Daguerre refined this process.
Daguerre first exposed silver-coated copper plates to iodine, obtaining silver iodide.
Then he exposed them to light for several minutes, coated the plate with mercury vapor heated to 75° Celsius (to amalgamate the mercury with the silver) and finally fixing the image in salt water. These ideas led to the famous Daguerreotype. The resultant plate produced an exact reproduction of the scene. The image was laterally reversed -- as images in mirrors are -- unless a second mirror was used during exposure to flip the image. The image could only be viewed at an angle and needed protection from the air and fingerprints so was encased in a glass-fronted box.
Daguerreotypes were usually portraits; the rarer views are much sought-after and are more expensive. The portrait process took several minutes and required the subjects to remain stock still. Samuel Morse was astonished to learn that Daguerrotypes of streets of Paris did not show any humans, until he realized that due to the long exposure times all moving objects became invisible. The time was later reduced with the "faster" lenses such as Petzval's portrait lens, the first mathematically calculated lens. In 1849, Daguerreotype images photographed by the famous Russian photographer Sergei Lvovich Levitsky (1819-1898) while on a mission to the Caucasus in 1843, were exhibited by the famous Parisian optician Chevalier at the Paris Exposition of the Second Republic as an advertisement of their lenses.
Levitsky's use of the Chevalier lens which used two cemented double lenses improved the camera's focusing ability, thus reducing the time needed to capture an image for portraiture and landscape photography. Levitsky's Daguerreotypes would receive the Exposition's gold medal; the first time a prize of its kind had ever been awarded to a photograph. The Daguerreotype was the Polaroid of the day, producing a single image which was not reproducible (unlike the Talbot process). Despite this drawback, millions of Daguerreotypes were produced. By 1851, the year of Daguerre's death, the Fox Talbot negative process was refined by the development of the wet collodion process, whereby a glass negative enabled a limitless number of sharp prints to be made. These developments made the Daguerreotype redundant and the process very soon disappeared.
