Photography (Greek "drawing with light" from photos = light, and graphis = stylus, paintbrush or graphê = representation by means of lines, drawing) is the technique of recording, by chemical or mechanical means, a permanent image on a layer of material sensitive to light exposure.
Image forming devices
Most commonly a camera or camera obscura is the image forming device and photographic film is the recording medium but other methods are available. For instance, the photocopy or xerography machine forms permanent images but uses the transfer of static electrical charges rather than photographic film, hence the term electrophotography. The rayographs published by Man Ray in 1922 are images produced by the shadows of objects cast on the photographic paper, without the use of a camera.
Uses of photography
Photography can be classified under imaging technology and has gained the interest of scientists and artists from its inception. Scientists have used its capacity to make accurate recordings, such as Eadweard Muybridge in his study of human and animal locomotion (1887). Artists have been equally interested by this aspect but have also tried to explore other avenues than the photo-mechanical representation of reality, such as the pictorialist movement.
History of photography
The first photograph is considered to be an image produced in 1826 by
Nicéphore Niepce on a polished pewter plate covered
with a petroleum derivative called bitumen of Judea. It was produced with a
camera, and required an eight hour exposure in bright sunshine. In 1839
Jacques Daguerre developed a process using silver on a copper plate called the
Daguerreotype. Almost at the same time, William Fox Talbot developed a different process called the calotype, using paper sheets covered with silver chloride. This process is much closer to the photographic process in use nowadays, as it produces a negative image that can be reused to produce several positive prints.
Having fun with photography: manipulation of the scanned print in a graphics program puts these two brave people on top of an Austrian cable car.
Click on the picture to see the three components.
The Daguerreotype proved more popular as it responded to the demand for portraiture emerging from the middle classes during the Industrial Revolution. This demand, that could not be met in volume and in cost by oil painting, may well have been the push for the development of photography. Neither of the techniques involved, the camera obscura, and the photo sensitivity of silver salts, were 19th century discoveries. Camera obscura were used by artists in the 16th century, as an aid to sketches for paintings, and the photo-sensitivity of a silver nitrate solution was observed by Johann Schultze in 1724.
Ultimately, the modern photographic process came about from a series of refinements and improvements on the foundations laid by William Fox Talbot. Photography became available for the mass-market in 1901 with the introduction of the Kodak Brownie camera, and, more importantly, with the industrialisation of film processing and printing. Very little has changed in principle since then, though color film has become the standard, and automatic focus and automatic exposure. For the enthusiast photographer processing black and white film, little has changed since the introduction of the 35mm film Leica camera in 1925.
Color photography was explored throughout the 1800s. Initial experiments in color could not fix the photograph and prevent the color from fading. The first permanent color photo was taken in 1861 by the physicist James Clerk Maxwell. The first color film, Autochrome, did not reach the market until 1907 and was based on dyed dots of potato starch. The first modern color film, Kodachrome, was introduced in 1935 based on three colored emulsions. Most modern color films, except Kodachrome, are based on technology developed for Agfacolor in 1936. Instant color film was introduced by Polaroid in 1963.
Traditional photography was a considerable burden for photographers working at remote locations (such as press correspondents) without access to processing facilities. With increased competition from television, there was pressure to deliver their images to newspapers ever faster. Photo-journalists at remote locations would carry a miniature photo lab with them, and some means of transmitting their images down the telephone line. In 1990, Kodak unveiled the DCS 100, the first commercially available digital camera. Its cost precluded any use other than photojournalism and professional applications, but commercial digital photography was born.
In 10 years, digital cameras have become consumer products, and they are likely to gradually replace their traditional counterparts in most applications as the price of electronic components goes down and the image quality improves. However, "wet" photography will endure, as dedicated amateurs and skilled artists preserve the use of traditional materials and techniques.
Further articles in Wikipedia
Basic topics in photography