PHOTOGRAPHY

method of recording the permanent image of an object by the action of light, or related radiation, on a sensitive material. The word, derived from the Greek photos ("light") and graphien ("to draw"), was first used by Sir John F.W. Herschel in 1839. Louis-Jacques-Mand Daguerre announced the first commercially successful photographic process, the daguerreotype, in 1839. Two years later William Henry Fox Talbot patented his negative-positive calotype process, which became the forerunner of modern photographic processes. This was followed by the wet collodion process in 1851 and by dry plates in 1871. Flexible films were introduced in 1889 by George Eastman. Since then, the light sensitivity (speed) of films has been greatly improved, and the quality of film emulsions has become so fine that prints many times larger than the size of the film can be made. Colour photography, expensive and complicated in the 19th century, has been so refined that it is nearly as easy as black-and-white photography. Technical improvements in the camera have transformed it from a bulky, cumbersome apparatus to a compact, sophisticated device that is often small enough to fit in a pocket. The development of photography has had a profound effect on society. At first its main use was in portraiture and in showing people the sights of the world. In the 1850s and '60s, Roger Fenton and Mathew B. Brady pioneered war photography and founded photojournalism, which has become pervasive in modern mass media. Professional photography now covers an enormous range of activities. To make a photograph, one must first form an image on a light-sensitive plate or film in a camera by means of a system of lenses in the camera. The plate or film may be of cellulose acetate, glass, or other transparent material coated with an emulsion of a halide (or salt) of silver, such as silver bromide or silver chloride. After exposure to light for a certain time period, the film is removed from the camera and placed in a chemical developer solution that yields fine, black silver particles. The particles cluster where light was strongest on the film, producing a reverse, or negative, image of the light and shadow of the object photographed. The particles are chemically fixed on the negative by washing in a fixer, which is frequently a solution of sodium thiosulfate called hypo. Other chemicals dissolve the unexposed silver salts, which are then washed out with water. An accurate positive image, or photograph, is made on special sensitized paper by placing the finished negative over the paper and exposing it to light. The lightest portions of the negative transmit the most light, and darker portions screen out more light, so that the negative image is reversed on the print. This positive image is fixed and washed in a process similar to the one used to produce the negative. In instant-print photography the processing chemicals are included in the film or camera, and the pictures are processed immediately upon their removal from the camera. Film intended to produce slides can be processed to bypass the negative stage. Such "reversal" films are commonly used to produce colour transparencies and, rarely, black-and-white ones. Colour photography is accomplished by two basic methods. In the additive processes, now seldom used, the subject is photographically separated into its blue, green, and red components (three-colour process), and negative images are used to combine blue, green, and red light to reproduce the subject with the same proportions of colours as in the original. In subtractive processes, positives are made in colours complementary (yellow, magenta, and cyan) to negative images photographed by blue, green, and red light; the three positive layers superimposed on each other reproduce the colours present in the original subject. Infrared photography is used to record the image of an object by using film sensitive to invisible infrared radiation instead of to ordinary light. Hot objects emit infrared rays and may be photographed in the dark, showing details of temperature distribution over the surface. Distant objects may be photographed with improved clarity because infrared light is not scattered as much by atmospheric haze as is ordinary light. The technique is widely used in astronomy; nebulae and stars that are invisible because of haze may be photographed by infrared photography. It has been applied to detect irregularities in treated and dyed textiles; to decipher old or altered documents; in aerial photography to observe pollution in streams and lakes and to detect diseased trees in forests; and by the military to distinguish painted camouflage from foliage, chlorophyll being transparent to infrared radiation. Ultraviolet photography is a method of making a photograph of an object illuminated with ultraviolet rather than ordinary visible light. In the direct method, a plate or film sensitive to ultraviolet light is exposed to the ultraviolet rays reflected off the object. In the fluorescence method, an ultraviolet light induces fluorescence, or the production of visible light, in the object, and this fluorescent light provides the illumination for the photograph. Ultraviolet photography, with its capability of detecting characteristic fluorescences, serves as a tool for identifying paintings, ceramics, grades of paper, and erasures in documents. Because of the excessive scattering of the short wavelengths of ultraviolet by the atmosphere, ultraviolet photography is not adapted to landscape photography; such photos appear blurred and show no shadows. method of recording the image of an object by the action of light, or related radiation, on a sensitive material. The word, derived from the Greek photos ("light") and graphein ("to draw"), was first used by the scientist Sir John F.W. Herschel in 1839. The term photography usually refers to the formation of optical images projected by a lens in a camera onto a film or other material carrying a layer of light-sensitive silver salts and the duplication and reproduction of such images by light action (printing); in an extended sense it also includes the formation of images by certain invisible radiations (ultraviolet and infrared rays) and images recorded in other sensitive materials not containing silver by means of chemical or physical processes or both. Related processes include the recording of images by X rays, electron beams, and nuclear radiations (radiography) and the recording and transmission of light images in the form of electromagnetic signals (television and videotape). This article treats the historical and aesthetic aspects of still photography. For a similar treatment of motion-picture photography, or cinematography, see motion picture. As a means of visual communication and expression, photography has marked aesthetic capabilities. In order to understand them, the characteristics of the process itself must first be understood. Of these the first is immediacy. Usually, but not necessarily, the image that is recorded is formed by a lens in a camera. Upon exposure to the light forming the image, the sensitive material undergoes changes in its structure; a latent image is formed, which becomes visible by development and permanent by fixing. With modern materials, the processing may take place immediately or may be delayed for weeks or months. But, either way, the elements of the final image are determined at the time of exposure. This characteristic is unique to photography and sets it apart from other ways of picture making. Although the photographer can control the character of the original image he captured upon film by the way he develops the negative and prints it, he cannot alter it except by manual interference. A second characteristic of the photograph is that it can contain more than the photographer intended it to. The first daguerreotypes, shown to an astounded public in Paris in the winter of 1838-39 by the inventor Louis-Jacques-Mand Daguerre, were praised because of the amount of detail recorded by them; looking at one with a magnifying glass, it was said, was like looking at nature with a telescope. The rival inventor of photography, William Henry Fox Talbot, after noting this characteristic, commented: It frequently happens, moreover-and this is one of the charms of photography-that the operator himself discovers on examination, perhaps long afterwards, that he has depicted many things he had no notion of at the time. Sometimes inscriptions and dates are found upon the buildings, or printed placards most irrelevant, are discovered upon their walls: sometimes a distant dial-plate is seen, and upon it-unconsciously recorded-the hour of the day at which the view was taken. As technological advances have improved photographic equipment, materials, and techniques, the scope of photography has expanded enormously. High-speed photography has made visible certain aspects of motion never before seen; with material sensitive to invisible radiation, hidden aspects of nature can be revealed; and, by a combination of photographic, electronic, and space technology, even the planets can be observed in new ways. Photography pervades every sphere of activity in modern civilization. Its thousandfold applications have made it indispensable in daily life. Photography disseminates information about humanity and nature, records the visible world, and extends human knowledge into areas the eye cannot penetrate. Next to the printed word the image drawn by light is the most important means of communication, and for this reason photography has been aptly called the most important invention since the printing press. The seemingly automatic recording of an image by photography has given the process a sense of authenticity shared by no other picture-making technique. The fact that the photograph can show more than the eye can see and that the image is not filtered through the brain of a man and put down by the skill of his hand has given it value as evidence. The photograph has become, in the popular mind, so much a substitute for reality and of such apparent accuracy that the adage "The camera does not lie" has become a clich. This intrinsic characteristic is of such strength that it has dominated the evaluation of photography's role in the arts. In the past photography was sometimes belittled as a mechanical art because of its dependence on technology. It has also been used over and over again as a foil by art critics to denounce paintings that rely heavily upon exact representation of subject matter. Indeed, after reviewing the daguerreotype process, the painter and art expert Paul Delaroche, who served on the committee that advised the French government to purchase the rights to the new process, declared: "From today painting is dead." In truth, photography is not the automatic process that is implied by the use of a camera. A fully automatic camera can produce a correctly exposed and sharp negative, but it cannot distinguish between a banal snapshot and a well-composed picture. The ability to make such a distinction rests solely with the person behind the camera. The creative photographer perceives the essential qualities of the subject and interprets it according to his judgment, taste, and involvement. The mechanical photographer merely reproduces what he sees. Although the camera does limit the photographer to depicting existing objects rather than imaginary or interpretive views, the skilled photographer has at his command a wide variety of controls that can be used to overcome the constraints of literalness and to introduce creativity into the mechanical reproduction process. The image can be modified by different lenses and filters. The type of sensitive material used to record the image is a further control, and the contrast between highlight and shadow can be changed by variations in development. In printing the negative, the photographer has a wide choice in the physical surface of the paper, the tonal contrast, and the image colour. The most important control is, of course, the photographer's vision. He chooses the vantage point and the exact moment of exposure. Through experience he knows how the camera will record what he sees. He learns to pre-visualize the final print. If he has visual imagination and perception, he can make more than a passive record. He can express universal qualities. He can extend the vision of the viewer. So facile a medium is photography that it is difficult to grasp its aesthetic capabilities and accomplishments. Of the billions of photographs that are taken every year, only a relatively small number can be considered art. Few camera users are deliberately concerned with the production of photographs to be judged as art. A far greater number look upon photography as a means of communication. While the aim of the commercial photographer, the photojournalist, and the scientist may not primarily be aesthetic, it is significant and remarkably characteristic of the medium that often in their work can be found memorable pictures that reach beyond the particular to the universal. Recognition plays an overwhelming role in photography: recognition by the creative photographer of the picture possibilities presented to him and recognition by the viewer of aesthetic qualities in photographs that he sees. Additional reading General works General reference works on photography include International Center of Photography, Encyclopedia of Photography (1984); and the volumes in the "Life Library of Photography" series by the editors of Time-Life Books, on the art and history of photography, types of photography, and techniques and processes. See also Turner Browne and Elaine Partnow, Macmillan Biographical Encyclopedia of Photographic Artists & Innovators (1983); Michele Auer and Michel Auer, Encyclopedie internationale des photographes de 1839 a nos jours: Photographers Encyclopaedia International 1839 to the Present (1985); and Colin Naylor (ed.), Contemporary Photographers, 2nd ed. (1988). The history and art of photography Historical overviews of the development of the art of photography are provided in Robert Taft, Photography and the American Scene: A Social History, 1839-1889 (1938, reprinted 1964); Helmut Gernsheim, Creative Photography: Aesthetic Trends, 1839-1960 (1962); Peter Pollack, The Picture History of Photography: From the Earliest Beginnings to the Present Day, rev. and enlarged ed. (1969), especially valuable for its wealth of illustrations; William Welling, Photography in America: The Formative Years, 1839-1900 (1978, reprinted 1987); Petr Tausk, Photography in the 20th Century (1980; originally published in German, 1977); Beaumont Newhall, The History of Photography: From 1839 to the Present, rev. and enlarged ed. (1982), the stylistic development of the art of photography as related to the technological and scientific characteristics of the medium; Naomi Rosenblum, A World History of Photography (1984); Peter Turner (ed.), American Images: Photography 1945-1980 (1985); and Jean-Claude Lemagny and Andr Rouill (eds.), A History of Photography: Social and Cultural Perspectives (1987; originally published in French, 1986).Essays on art and photography can be found in Charles H. Caffin, Photography as a Fine Art: The Achievements and Possibilities of Photographic Art in America (1901, reissued 1972); Irving Penn, Moments Preserved: Eight Essays in Photographs and Words (1960); Nathan Lyons (ed.), Photographers on Photography: A Critical Anthology (1966), essays by photographers from the 1890s to the 1960s; John Szarkowski, The Photographer's Eye (1966, reissued 1980), a penetrating examination of photographic aesthetics; Aaron Scharf, Art and Photography (1968, reprinted 1986); Volker Kahmen, Photography as Art (1974; originally published in German, 1973); Jean-Luc Daval, Photography, History of an Art (1982; originally published in French, 1982); Bryan Holme (ed.), Photography as Fine Art (1983); and Andy Grundberg and Katherine McCarthy Gauss, Photography and Art: Interactions Since 1946 (1987), photographs from an exhibition.Studies of particular schools and types of photography include Robert Doty, Photo Secession: Photography as a Fine Art (1960, reprinted with title Photo-Secession: Stieglitz and the Fine-Art Movement in Photography, 1978), an account of events leading up to and following the founding of the society by Alfred Stieglitz; William Culp Darrah, Stereo Views: A History of Stereographs in America and Their Collection (1964); French Primitive Photography (1969), a catalog of an exhibition; Richard Rudisill, Mirror Image: The Influence of the Daguerreotype on American Society (1971), a thorough survey; Van Deren Coke, The Painter and the Photograph: From Delacroix to Warhol, rev. and enlarged ed. (1972), an exhibition catalog; Beaumont Newhall, The Daguerreotype in America, 3rd rev. ed. (1976), a study of the industry as well as the art of daguerreotyping; Ben Maddow, Faces: A Narrative History of the Portrait in Photography (1977); Margaret Harker, The Linked Ring: The Secession Movement in Photography in Britain, 1892-1910 (1979); Van Deren Coke, Avant-Garde Photography in Germany, 1919-1939, trans. from German (1982); Rainer Fabian and Hans-Christian Adam, Masters of Early Travel Photography (1983; originally published in German, 1981); and Bauhaus Photography (1985; originally published in German, 1982). See also Beaumont Newhall and Nancy Newhall (eds.), Masters of Photography (1958, reissued 1982); short biographical sketches of 19 photographers, with representative photographs by each.Photojournalism as a separate form is discussed in Wilson Hicks, Words and Pictures: An Introduction to Photojournalism (1952, reissued 1973); Ken Baynes (ed.), Scoop, Scandal, and Strife: A Study of Photography in Newspapers (1971); and John R. Whiting, Photography Is a Language (1946, reprinted 1979). See also Stanley Rayfield, How Life Gets the Story: Behind the Scenes in Photojournalism (1955), field experience of photographers from Life, presented in the format and photographic essay style of the magazine. Beaumont Newhall Helmut Erich Robert Gernsheim