| Film | Cameras | Lenses | Lighting FilmA Brief History of FilmScientists recognized the photosensitivity of certain silver compounds, particularly silver nitrate and silver chloride, during the 18th century. In the early 19th century English scientists Thomas Wedgwood and Sir Humphry Davy used silver nitrate in an attempt to transfer a painted image onto leather or paper. While they succeeded in producing a negative image, it was not permanent; the entire surface blackened after continued exposure to light. A French inventor, Joseph Nicéphore Niépce, is credited with having made the first successful photograph in 1826. He achieved this by placing a pewter plate coated with bitumen, another light-sensitive material, in the back of a camera obscura. Niépce later switched from pewter to copper plates and from bitumen to silver chloride. French painter Louis Jacques Daguerre announced an improved version of the process, which he called the Daguerreotype, in 1939. The Daguerreotype process produced a positive image on a copper plate small enough to be held in the hand. Daguerreotypes remained popular through the 1850s, but were eventually replaced by a negative/positive process developed by English inventor William H. Talbot in the 1840s. Talbot’s process produced a paper negative, from which he could produce any number of paper positives. He exposed silver-sensitized paper briefly to light and then treated it with other chemicals to produce a visible image. In 1850, glass replaced paper as a support for the negative, and the silver salts were suspended in collodion, a thick liquid. The smooth glass negatives could produce sharper images than paper, because the details were no longer lost in the texture of the paper. This refinement became known as the wet collodion (or wet plate) process. Because the wet plate process required photographers to coat the glass support just before taking a picture, experimenters sought a dry version of the same process. Dry plates, pieces of glass coated in advance with an emulsion of gelatin and silver bromide, were invented in 1878. American inventor George Eastman developed a flexible version--a paper strip--that would replace the glass plate. In 1889, he produced the first photographic film using celluloid. Eastman's invention paved the way for all modern films, which are made of acetate or polyester, plastics that are less flammable than celluloid. A practical color film was not invented until late in the first decade of the twentieth century. Autochrome, as it was named, became available in 1907 and was based on a process devised by French inventors Auguste and Louis Lumière. Color photography took hold when Kodak introduced Kodachrome color film in 1935 and Agfacolor in 1936. Both of these films produced positive color transparencies, or slides. The Kodak company introduced Kodacolor film for color negatives in 1942, which gave amateurs the same negative/positive process they had long enjoyed in black and white. |