The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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and reference to Plane table and Oroheliograph under Pano-ramic Camera.) Standard works on Photogrammetry are Dr. C. Koppe's "Die Photogrammetrie," Weimar, 1889; Com-mander V. Legros' "Elements de Photogrammetrie/' Paris, 1892; and Dr. Le Bon's "Les Levers Photographiques," Paris, 1889 (2 vols.). For Professor Turner's new method with an ordinary camera, see The Amateur Photographer, January 23rd, 1902, p. 66.
Photography light, and
I draw) is the art of obtaining the representation of objects by the agency of light upon sensitive substances. The following is a short history of the rise and progress of the art: - In the sixteenth century Baptista Porta, a Neapolitan, popularised the Camera Obscura (g.v.), and this was used to obtain sketches by hand of the objects projected by the lens. In 1777 Scheele, the great chemist, discovered the important fact that chloride of silver blackened in sunlight, the chief action lying in the violet end of the spectrum. In 1802, Thomas Wedgewood, son of the famous potter, published in the "Journal of the Royal Institu-tion " an account of a method of copying paintings on glass, and of making profiles by the agency of light upon nitrate of silver. In the experiments which are thus described he was assisted by Sir Humphrey Davy. They managed to obtain images upon paper and white leather by means of the solar microscope, but were unable to fix them; therefore the image was soon obliterated by the darkening of the whole surface. In 1814 Nicephore de Niepce commenced a series of experiments, but although he managed to obtain images upon a bituminous film, the process was impracticable for ordinary purposes, from the inordinate exposure (several hours) which was required. He then, in partnership with Daguerre, carried on his experiments ; but it was not until 1839, six years after Niepce's death, that Daguerre communicated to the Academie des Sciences at Paris the process so well known as Daguerreotype. Early in 1839 Fox Talbot, previous to Daguerre's communications, announced to the Royal Society a method of "photogenic drawing," in which pictures were produced upon paper prepared with chloride of silver. Fox Talbot effected the fixation of these pictures by saturated solutions of chloride of sodium and bromide of potassium. The