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photography

[fuh-tog-ruh-fee]

photography, still, science and art of making permanent images on light-sensitive materials.

Early Developments

The camera itself is based on optical principles known at least since the age of Aristotle; indeed, a filmless version was in use in the mid-1500s as a sketching device for artists. Called the camera obscura (Lat.,=dark chamber), it consisted of a small, lightproof box with a pinhole or lens on one side and a translucent screen on the opposite side. This screen registered, in a manner suitable for tracing, the inverted image transmitted through the lens. The human eye was the prototype for this device, which functioned as a primitive extension of seeing. Most experiments in photographic technology were directed toward perfecting the medium as a surrogate, more sophisticated eye.

The Invention of Photography

The necessary first breakthrough in photography was in a different, not eye-centered area—that of making permanent photographic images. Employing data from the researches of Johann Heinrich Schulze—who, in 1727, discovered that silver nitrate darkened upon exposure to light—Thomas Wedgwood and Sir Humphry Davy, early in the 19th cent., created what we now call photograms. These were made by placing assorted objects on paper soaked in silver nitrate and exposing them to sunlight. Those areas of the paper covered by the objects remained white; the rest blackened after exposure to the light. Davy and Wedgwood found no way of arresting the chemical action at this stage, however, and their images lasted only a short time before darkening entirely.

Photography's basic principles, processes, and materials were discovered virtually simultaneously by a diverse group of individuals of different nationalities, working for the most part entirely independently of one another. The results of their experiments coalesced in the first half of the 19th cent., creating a tool for communication that was to become as powerful and significant as the printing press. Four men figure principally in the establishment of the rudiments of photographic science.

The French physicist, Joseph Nicéphore Niepce, made the first negative (on paper) in 1816 and the first known photograph (on metal; he called it a heliograph) in 1826. By the latter date he had directed his investigations away from paper surfaces and negatives (having invented, in the meantime, what is now called the photogravure process of mechanical reproduction) and toward sensitized metallic surfaces. In 1827 Niepce had also begun his association with Louis Jacques Mandé Daguerre, a French painter who had been experimenting along parallel lines. A partnership was formed and they collaborated until Niepce's death in 1833, after which Daguerre continued their work for the next six years. In 1839 he announced the invention of a method for making a direct positive image on a silver plate—the daguerreotype.

Daguerre's announcement was a source of dismay to the English scientist William Henry Fox Talbot, who had been experimenting independently along related lines for years. Talbot had evolved a method for making a paper negative from which an infinite number of paper positives could be created. He had also worked out an effective although imperfect technique for permanently "fixing" his images. Concerned that he might lose the rights to his own invention, the calotype process, Talbot wrote to the French Academy of Sciences, asserting the priority of his own invention. He then lost no time in presenting his researches to England's Royal Society, of which he was a distinguished member.

All three pioneers, Niepce, Daguerre, and Talbot, along with Sir John Herschel—who in 1819 discovered the suitability of hyposulfite of soda, or "hypo," as a fixing agent for sensitized paper images and who is generally credited with giving the new medium its name—deserve to share the title Inventor of Photography. Each made a vital and unique contribution to the invention of the photographic process. The process developed by Daguerre and Niepce was, in a grand gesture, purchased from them by the French government and given, free of patent restrictions, to the world. Talbot patented his own process and then published a description of it, entitled The Pencil of Nature (1844-46). This book, containing 24 original prints, was the first ever illustrated with photographs.

The Daguerreotype

Daguerreotypy spread rapidly, except in England, where Daguerre had secretly patented his process before selling it to the French government. The legal problems attending the pursuit of photography as a profession account in part for the widespread influence of amateurs (e.g., Nadar, the French pioneer photographer) on the early development of the medium. The popularity of the daguerreotype is attributable to two principal factors. The first of these was the Victorian passion for novelty and for the accumulation of material objects, which found its perfect paradigm in these silvery, exquisitely detailed miniatures. The second was the greatly increasing demand from a rising middle class for qualitatively good but—compared to a painter's fee—inexpensive family portraits. The cheaper tintype eventually made such likenesses available to all.

The principal shortcoming of the daguerreotype and its variants was inherent in its nature as a direct positive. Unique and unreproducible, it could not serve for the production of any image intended for wide distribution. This factor, combined with the lengthy exposure time necessitated by the process, restricted its function to portraiture. The vast majority of surviving daguerreotypes are portraits; images of any other subject are exceedingly rare. Nevertheless, for 20 years the daguerreotype completely overshadowed the greater utility of the calotype. In the United States, where it was equally popular, the daguerreotype was promoted by John W. Draper and Samuel F. B. Morse.

The Calotype

The calotype's paper negative made possible the reproduction of photographic images. The unavoidably coarse paper base for the negative, however, eliminated the delicate detail that made the daguerreotype so appealing. This lack of precision was understood and used to advantage by the Scottish painter David Octavius Hill and his assistant, Robert Adamson. From 1843 to 1848 they made an extensive series of calotype portraits of Scottish clergymen, intended to serve only as studies for a group portrait in oils, that stands today among the major bodies of work in the medium. Hill and Adamson composed their portraits in broad planes, juxtaposing bold masses of light and dark, creating works that are monumental in feeling despite their small size.

The Collodion Process

The dilemma of detail versus reproducibility was resolved in 1851 by an Englishman, Frederick Scott Archer, who introduced the collodion process. This method, also known as the "wet plate" technique, involved coating a glass plate with silver iodide in suspension, exposing it while still wet, and developing it immediately. Once fixed and dried, the glass plate was covered with a thin, flexible film containing the negative image, the definition and detail of which approached that of the daguerreotype. As this process merged the advantages of both its predecessors, it was universally adopted within a very short time.

The Impact of Early Photography

With the advent of the collodion process came mass production and dissemination of photographic prints. The inception of these visual documents of personal and public history engendered vast changes in people's perception of history, of time, and of themselves. The concept of privacy was greatly altered as cameras were used to record most areas of human life. The ubiquitous presence of photographic machinery eventually changed humankind's sense of what was suitable for observation. The photograph was considered incontestable proof of an event, experience, or state of being.

To fulfill the mounting and incessant demand for more images, photographers spread out to every corner of the world, recording all the natural and manufactured phenomena they could find. By the last quarter of the 19th cent. most households could boast respectable photographic collections. These were in three main forms: the family album, which contained cabinet portraits and the smaller cartes-de-visite and tintypes; scrapbooks containing large prints of views from various parts of the world; and boxes of stereoscope cards, which in combination with the popular stereo viewer created an effective illusion of three-dimensionality.

A number of photographers, including Timothy O'Sullivan, J. K. Hillers, and W. H. Jackson, accompanied exploratory expeditions to the new frontiers in the American West, while John Thomson returned from China and Maxime Du Camp from Egypt with records of vistas and peoples never before seen by Western eyes. Roger Fenton, who photographed the Crimean conflict, and Mathew Brady's photographic corps, who documented the American Civil War, provided graphic evidence of the hellishness of combat.

Further Developments

E. J. Marey, the painter Thomas Eakins, and Eadweard Muybridge all devised means for making stop-action photographs that demonstrated the gap between what the mind thinks it sees and what the eye actually perceives. Muybridge's major work, Animal Locomotion (1887), remains a basic source for artists and scientists alike. As accessory lenses were perfected, the camera's vision extended both telescopically and microscopically; the moon and the microorganism became accessible as photographic images.

The introduction of the halftone process (see photoengraving; printing) in 1881 made possible the accurate reproduction of photographs in books and newspapers. In combination with new improvements in photographic technology, including dry plates and smaller cameras, which made photographing faster and less cumbersome, the halftone made immediate reportage feasible and paved the way for news photography. George Eastman's introduction in 1888 of roll film and the simple Kodak box camera provided everyone with the means of making photographs for themselves. Meanwhile, studies in sensitometry, the new science of light-sensitive materials, made exposure and processing more practicable.

Art and Documentary Photography

The fight to certify photography as a fine art has been among the medium's dominant philosophical preoccupations since its inception. Photography's legitimacy as an art form was challenged by artists and critics, who seized upon the mechanical and chemical aspects of the photographic process as proof that photography was, at best, a craft. Perhaps because so many painters came to rely so heavily on the photograph as a source of imagery, they insisted that photography could only be a handmaiden to the arts.

To prove that photography was indeed an art, photographers at first imitated the painting of the time. Enormous popularity was achieved by such photographers as O. J. Rejlander and Henry Peach Robinson, who created sentimental genre scenes by printing from multiple negatives. Julia Margaret Cameron blurred her images to achieve a painterly softness of line, creating a series of remarkably powerful soft-focus portraits of her celebrated friends.

In opposition to the painterly aesthetic in photography was P. H. Emerson and other early advocates of what has since become known as "straight" photography. According to this approach the photographic image should not be tampered with or subjected to handwork or other affectations lest it lose its integrity. Emerson proposed this philosophy in his controversial and influential book, Naturalistic Photography (1889). Appropriately, Emerson was the first to recognize the importance of the work of Alfred Stieglitz, who battled for photography's place among the arts during the first part of the 20th cent.

In revolt against the entrenched imitation of genre painting known as "salon" photography, Stieglitz founded a movement which he called the Photo-Secession, related to the radical secession movements in painting. He initiated publication of a magazine, Camera Work (1903-17), which was a forum for the Photo-Secession and for enlightened opinion and critical thought in all the arts. It remains the most sumptuously and meticulously produced photographic quarterly in the history of the medium. In New York City, Stieglitz opened three galleries, the first (1908-17) called "291" (from its address at 291 Fifth Ave.), then the Intimate Gallery (1925-30), and An American Place (1930-46), where photographic work was hung beside contemporary, often controversial, work in other media.

Stieglitz's own photographs and those of several other Photo-Secessionists—Edward Steichen, one of his early protégés; Frederick Evans, the British architectural photographer; and the portraitist Alvin L. Coburn—adhered with relative strictness to a "straight" aesthetic. The quality of their works, despite a pervasive self-consciousness, was consistently of the highest craftsmanship. Stieglitz's overriding concern with the concept "art for art's sake" kept him, and the audience he built for the medium, from an appreciation of an equally important branch of photography: the documentary.

The power of the photograph as record was demonstrated in the 19th cent., as when William H. Jackson's photographs of the Yellowstone area persuaded the U.S. Congress to set that territory aside as a national park. In the early 20th cent. photographers and journalists were beginning to use the medium to inform the public on crucial issues in order to generate social change.

Taking as their precedents the work of such men as Jackson and reporter Jacob Riis (whose photographs of New York City slums resulted in much-needed legislation), documentarians like Lewis Hine and James Van DerZee began to build a photographic tradition whose central concerns had little to do with the concept of art. The photojournalist sought to build, strengthen, or change public opinion by means of novel, often shocking images. The finished form of the documentary image was the inexpensive multiple, the magazine or newspaper reproduction. For a time the two traditions, art photography and documentary photography, appeared to be merged within the work of one man, Paul Strand. Strand's works combined a documentary concern with a lean, modernist vision related to the avant-garde art of Europe.

The Aesthetics of Photography

Seeking to determine the particular aesthetics of photography, the American Berenice Abbott and the Frenchmen Eugène Atget, André Kertész, and Henri Cartier-Bresson developed intensely personal styles. The exponents of surrealism in France and of futurism in Italy and the various German art movements that were focused in the Bauhaus all explored the medium of photography. The international exhibition "Film und Foto," held in Stuttgart in 1929, helped to make formal a purely photographic aesthetic. The works exhibited combined elements of functionalism and abstraction. Photographic subject matter shifted from the past to the present—a present of new forms in machinery and architecture, new concern with the experience of the working classes, and a new interest in the timeless forms of nature.

In California during the 1920s and 30s Edward Weston and a handful of kindred spirits founded the f/64 group, taking their name from the smallest lens opening, that which provides the greatest precision of line and detail. This small and unofficial group—which included Imogen Cunningham, Ansel Adams, and Willard Van Dyke—came to dominate photographic art, overshadowing the pictorial aesthetic. They and their imitators eschewed all post-exposure handwork, and worked with 8 × 10-in. view cameras in order to obtain the largest possible negatives from which to make straightforward contact prints. They limited their subject matter to static things: the still life, the distant or closely viewed landscape, and the formal portrait. The influential teacher Minor White became known for his poetic, visionary work related in technique to this straight approach.

The Impact of New Technology

The development of the 35-mm or "candid" camera by Oskar Barnack of the Ernst Leitz company, first marketed in 1925, made documentarians infinitely more mobile and less conspicuous, while the manufacture of faster black-and-white film enabled them to work without a flash in situations with a minimum of light. Color film for transparencies (slides) was introduced in 1935 and color negative film in 1942. Portable lighting equipment was perfected, and in 1947 the Polaroid Land camera, which could produce a positive print in seconds, was placed on the market. All of these technological advances granted the photojournalist enormous and unprecedented versatility.

The advent of large-circulation picture magazines, such as Life (begun 1936) and Look (begun 1937), provided an outlet and a vast audience for documentary work. At the same time a steady stream of convulsive national and international events provided a wealth of material for the extended photo-essay, the documentarian's natural mode. One of these was the Great Depression of the 1930s, which proved to be the source of an important body of documentary work. Under the leadership of Roy Stryker, the photographic division of the Farm Security Administration (FSA) began to make an archive of images of America during this epoch of crisis. Walker Evans, Arthur Rothstein, Russell Lee, and Dorothea Lange of the FSA group photographed the cultural disintegration generated by the Depression and the concomitant disappearance of rural lifestyles.

With the coming of World War II photographers, including Margaret Bourke-White, Edward Steichen, W. Eugene Smith, Lee Miller, and Robert Capa, documented the global conflict. The war was a stimulus to photography in other ways as well. From the stress analysis of metals to aerial surveillance, the medium was a crucial tool in many areas of the war effort, and, in the urgency of war, numerous technological discoveries and advances were made that ultimately benefited all photographers.

Modern Photography

After the war museums and art schools opened their doors to photography, a trend that has continued to the present. Photographers began to break free of the oppressive strictures of the straight aesthetic and documentary modes of expression. As exemplified by Robert Frank in his highly influential book-length photo-essay, The Americans (1959), the new documentarians commenced probing what has been called the "social landscape," often mirroring in their images the anxiety and alienation of urban life. Such introspection naturally led to an increasingly personal form of documentary photography, as in the works of J. H. Lartigue and Diane Arbus.

Many young photographers felt little inhibition against handwork, collage, multiple images, and other forms that were anathema to practitioners of the straight aesthetic. Since the 1960s photography has become an increasingly dominant medium within the visual arts. Many painters and printmakers, including Andy Warhol, Robert Rauschenberg, and David Hockney have blended photography with other modes of expression, including computer imaging in mixed media compositions at both large and small scale. Contemporary photographers who use more traditional methods to explore non-traditional subjects include Cindy Sherman and Richard Prince.

The 1990s brought the first attempt to provide a fully integrated photographic system. Aimed at the amateur photographer, the Advanced Photo System (APS) was developed by an international consortium of camera and film manufacturers. The keystone of the new system is a magnetic coating that enables the camera, film, and photofinishing equipment to communicate. The cameras are self-loading, can be switched among three different formats (classic, or 4 by 6 in.; hi vision, or 4 by 7 in.; and panoramic, or 4 by 11.5 in.), and are fully automatic (auto-focus, auto-exposure—"point-and-shoot"). The film is a new, smaller size (24 mm), has an improved polyester plastic base, and two magnetic strips that record the exposure and framing parameters for each picture and allow the user to add a brief notation to each frame. The photofinishing equipment can read the magnetic data on the film and adjust the developing of each negative to compensate for the conditions. After processing, the negatives (still encased in the cassette) are returned along with the photographs and an index sheet of thumbnail-size contact prints from which reprints and enlargements can be selected.

Other Aspects of Photography

In the contemporary world the practical applications of the photographic medium are legion: it is an important tool in education, medicine, commerce, criminology, and the military. Its scientific applications include aerial mapping and surveying, geology, reconnaissance, meteorology, archaeology, and anthropology. New techniques such as holography, a means of creating a three-dimensional image in space, continue to expand the medium's technological and creative horizons. In astronomy the charge coupled device (CCD) can detect and register even a single photon of light.

Digital Technology

By the end of the 20th cent. digital imaging and processing and computer-based techniques had made it possible to manipulate images in many ways, creating revolutionary changes in photography. Digital technology allowed for a fundamental change in the nature of photographic technique. Instead of light passing through a lens and striking emulsion on film, digital photography uses sensors and color filters. In one technique three filters are arranged in a mosaic pattern on top of the photosensitive layer. Each filter allows only one color (red, green, or blue) to pass through to the pixel beneath it. In the other technique, three separate photosensitive layers are embedded in silicon. Since silicon absorbs different colors at different depths, each layer allows a different color to pass through. When stacked together, a full color pixel results. In both techniques the photosensitive material converts images into a series of numbers that are then translated back into tonal values and printed. Using computers, various numbers can easily be changed, thus altering colors, rearranging pictorial elements, or combining photographs with other kinds of images. Some digital cameras record directly onto computer disks or into a computer, where the images can be manipulated at will.

Bibliography

See B. Newhall, The History of Photography: 1839 to the Present Day (5th rev. ed. 1982); R. Bolton, Contest of Meaning (1992); G. Batchen, Burning with Desire: The Conception of Photography (1999); J. Szarkowski, Looking at Photographs (1999); M. J. Langford, Basic Photography (2001); T. Ang, Digital Photography: An Introduction (2003). Among the many outstanding volumes of collected photographs are E. Steichen, ed., The Family of Man (1955) and American Album (1968; comp. by the ed. of American Heritage); V. Goldberg, Photography in Print (1988); W. J. Mitchell, The Reconfigured Eye: Visual Truth in the Post-Photographic Age (1993).

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photography

Method of recording permanent images by the action of light projected by a lens in a camera onto a film or other light-sensitive material. It was developed in the 19th century through the artistic aspirations of two Frenchmen, Nicéphore Niepce and Louis-Jacques-Mandé Daguerre, whose combined discoveries led to the invention of the first commercially successful process, the daguerreotype (1837). In addition, two Englishmen, Thomas Wedgwood and William Henry Fox Talbot, patented the negative-positive calotype process (1839) that became the forerunner of modern photographic technique. Photography was initially used for portraiture and landscapes. In the 1850s and '60s, Mathew B. Brady and Roger Fenton pioneered war photography and photojournalism. From its inception, two views of photography predominated: one approach held that the camera and its resulting images truthfully document the real world, while the other considered the camera simply to be a tool, much like a paintbrush, with which to create artistic statements. The latter notion, known as Pictorialism, held sway from the late 1860s through the first decade of the 20th century, as photographers manipulated their negatives and prints to create hazy, elaborately staged images that resembled paintings. By the 1920s and '30s, a new, more realistic style of photography gained prominence, as photographers such as Paul Strand, Edward Weston, and Ansel Adams began to pursue sharply focused, detailed images. The Great Depression and two world wars inspired many photographers, including Walker Evans and Dorothea Lange, to pursue documentary, often socially conscious photography. Inspired by such work, many photojournalists, including Alfred Eisenstaedt and Margaret Bourke-White, also emerged during this period. In the second half of the 20th century, the urban social scene became a subject of much interest to photographers, as did celebrity portraiture and fashion photography. At the turn of the 21st century, photographers took advantage of digital capabilities by experimenting with enormous formats and new manipulative techniques. As technological advances improve photographic equipment, materials, and techniques, the scope of photography continues to expand enormously. Seealso digital camera.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.

Photography

Photography (fә'tɒgrәfi or fә'tɑːgrәfi) (from Greek φωτο and γραφία) is the process and art of recording pictures by means of capturing light on a light-sensitive medium, such as a film or an electronic sensor. Light patterns reflected or emitted from objects expose a sensitive silver halide based chemical or electronic medium during a timed exposure, usually through a photographic lens in a device known as a camera that also stores the resulting information chemically or electronically. Photography has many uses for business, science, art and pleasure.

The word "photography" comes from the French photographie which is based on the Greek φώς (phos) "light" + γραφίς (graphis) "stylus", "paintbrush" or γραφή (graphê) "representation by means of lines" or "drawing", together meaning "drawing with light." Traditionally, the product of photography has been called a photograph, commonly shortened to photo.

Photographic cameras

The camera or camera obscura is the image-forming device, and photographic film or a silicon electronic image sensor is the sensing medium. The respective recording medium can be the film itself, or a digital electronic or magnetic memory.

Photographers control the camera and lens to "expose" the light recording material (such as film) to the required amount of light to form a "latent image" (on film) or "raw file" (in digital cameras) which, after appropriate processing, is converted to a usable image. Digital cameras replace film with an electronic image sensor based on light-sensitive electronics such as charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology. The resulting digital image is stored electronically, but can be reproduced on paper or film.

In all but certain specialized cameras, the process of obtaining a usable exposure must involve the use, manually or automatically, of a few controls to ensure the photograph is clear, sharp and well illuminated. The controls usually include but are not limited to the following:

Focus - the adjustment to place the sharpest focus where it is desired on the subject.
Aperture – adjustment of the iris, measured as f-number, which controls the amount of light passing through the lens. Aperture also has an effect on focus and depth of field, namely, the smaller the opening [aperture], the less light but the greater the depth of field--that is, the greater the range within which objects appear to be sharply focused.
Shutter speed – adjustment of the speed (often expressed either as fractions of seconds or as an angle, with mechanical shutters) of the shutter to control the amount of time during which the imaging medium is exposed to light for each exposure. Shutter speed may be used to control the amount of light striking the image plane; 'faster' shutter speeds (that is, those of shorter duration) decrease both the amount of light and the amount of image blurring from motion of the subject and/or camera.
White balance – on digital cameras, electronic compensation for the color temperature associated with a given set of lighting conditions, ensuring that white light is registered as such on the imaging chip and therefore that the colors in the frame will appear natural. On mechanical, film-based cameras, this function is served by the operator's choice of film stock. In addition to using white balance to register natural coloration of the image, photographers may employ white balance to aesthetic end, for example white balancing to a blue object in order to obtain a warm color temperature.
Metering – measurement of exposure so that highlights and shadows are exposed according to the photographer's wishes. Many modern cameras meter and set exposure automatically. Before automatic exposure, correct exposure was accomplished with the use of a separate light metering device or by the photographer's knowledge and experience of gauging correct settings. To translate the amount of light into a usable aperture and shutter speed, the meter needs to adjust for the sensitivity of the film or sensor to light. This is done by setting the "film speed" or ISO sensitivity into the meter.
ISO speed – traditionally used to "tell the camera" the film speed of the selected film on film cameras, ISO speeds are employed on modern digital cameras as an indication of the system's gain from light to numerical output and to control the automatic exposure system. A correct combination of ISO speed, aperture, and shutter speed leads to an image that is neither too dark nor too light.
Auto-focus point – on some cameras, the selection of a point in the imaging frame upon which the auto-focus system will attempt to focus. Many Single-lens reflex cameras (SLR) feature multiple auto-focus points in the viewfinder.

Many other elements of the imaging device itself may have a pronounced effect on the quality and/or aesthetic effect of a given photograph; among them are:

Focal length and type of lens (telephoto or "long" lens, macro, wide angle, fisheye, or zoom)
Filters placed between the subject and the light recording material, either in front of or behind the lens
Inherent sensitivity of the medium to light intensity and color/wavelengths.
The nature of the light recording material, for example its resolution as measured in pixels or grains of silver halide.

Controlling the photographic exposure and rendering

Camera controls are inter-related. The total amount of light reaching the film plane (the "exposure") changes with the duration of exposure, aperture of the lens, and, the effective focal length of the lens (which in variable focal length lenses, can change as the lens is zoomed). Changing any of these controls can alter the exposure. Many cameras may be set to adjust most or all of these controls automatically. This automatic functionality is useful for occasional photographers in many situations.

The duration of an exposure is referred to as shutter speed, often even in cameras that don't have a physical shutter, and is typically measured in fractions of a second. Aperture is expressed by an f-number or f-stop (derived from focal ratio), which is proportional to the ratio of the focal length to the diameter of the aperture. If the f-number is decreased by a factor of $sqrt 2$ , the aperture diameter is increased by the same factor, and its area is increased by a factor of 2. The f-stops that might be found on a typical lens include 2.8, 4, 5.6, 8, 11, 16, 22, 32, where going up "one stop" (using lower f-stop numbers) doubles the amount of light reaching the film, and stopping down one stop halves the amount of light.

Exposures can be achieved through various combinations of shutter speed and aperture. For example, f/8 at 8 ms (=1/125th of a second) and f/5.6 at 4 ms (=1/250th of a second) yield the same amount of light. The chosen combination has an impact on the final result. In addition to the subject or camera movement that might vary depending on the shutter speed, the aperture (and focal length of the lens) determine the depth of field, which refers to the range of distances from the lens that will be in focus. For example, using a long lens and a large aperture (f/2.8, for example), a subject's eyes might be in sharp focus, but not the tip of the nose. With a smaller aperture (f/22), or a shorter lens, both the subject's eyes and nose can be in focus. With very small apertures, such as pinholes, a wide range of distance can be brought into focus.

Image capture is only part of the image forming process. Regardless of material, some process must be employed to render the latent image captured by the camera into the final photographic work. This process consists of two steps, development, and printing.

During the printing process, modifications can be made to the print by several controls. Many of these controls are similar to controls during image capture, while some are exclusive to the printing process. Most controls have equivalent digital concepts, but some create different effects. For example, dodging and burning controls are different between digital and film processes. Other printing modifications include:

Chemicals and process used during film development
Duration of exposure – equivalent to shutter speed
Printing aperture – equivalent to aperture, but has no effect on depth of field
Contrast
Dodging – reduces exposure of certain print areas, resulting in lighter areas
Burning – increases exposure of certain areas, resulting in darker areas
Paper texture – glossy, matte, etc
Paper type – resin-coated (RC) or fiber-based (FB)
Paper size
Toners – used to add warm to cool tones to black and white

Uses of photography

Photography gained the interest of many scientists and artists from its inception. Scientists have used photography to record and study movements, such as Eadweard Muybridge's study of human and animal locomotion in 1887. Artists are equally interested by these aspects but also try to explore avenues other than the photo-mechanical representation of reality, such as the pictorialist movement. Military, police, and security forces use photography for surveillance, recognition and data storage. Photography is used to preserve memories of favorite times, to capture special moments, to tell stories, to send messages, and as a source of entertainment.

Commercial advertising relies heavily on photography and has contributed greatly to its development.

History of photography

Photography is the result of combining several technical discoveries. Long before the first photographs were made, Ibn al-Haytham (Alhazen) (965–1040) invented the camera obscura and pinhole camera, Albertus Magnus (1193–1280) discovered silver nitrate, and Georges Fabricius (1516–1571) discovered silver chloride. Daniel Barbaro described a diaphragm in 1568. Wilhelm Homberg described how light darkened some chemicals (photochemical effect) in 1694. The fiction book Giphantie, by French author Tiphaigne de la Roche, described what can be interpreted as photography.

Photography as a usable process goes back to the 1820s with the development of chemical photography. The first permanent photograph was an image produced in 1826 by the French inventor Nicéphore Niépce. However, the picture took eight hours to expose, so he went about trying to find a new process. Working in conjunction with Louis Daguerre, they experimented with silver compounds based on a Johann Heinrich Schultz discovery in 1724 that a silver and chalk mixture darkens when exposed to light. Niépce died in 1833, but Daguerre continued the work, eventually culminating with the development of the daguerreotype in 1837. Eventually, France agreed to pay Daguerre a pension for his formula, in exchange for his promise to announce his discovery to the world as the gift of France, which he did in 1839.

Meanwhile, Hercules Florence had already created a very similar process in 1832, naming it Photographie, and William Fox Talbot had earlier discovered another means to fix a silver process image but had kept it secret. After reading about Daguerre's invention, Talbot refined his process so that it might be fast enough to take photographs of people. By 1840, Talbot had invented the calotype process, which creates negative images. John Herschel made many contributions to the new methods. He invented the cyanotype process, now familiar as the "blueprint". He was the first to use the terms "photography", "negative" and "positive". He discovered sodium thiosulphate solution to be a solvent of silver halides in 1819, and informed Talbot and Daguerre of his discovery in 1839 that it could be used to "fix" pictures and make them permanent. He made the first glass negative in late 1839.

In March 1851, Frederick Scott Archer published his findings in "The Chemist" on the wet plate collodion process. This became the most widely used process between 1852 and the late 1880s when the dry plate was introduced. There are three subsets to the Collodion process; the Ambrotype (positive image on glass), the Ferrotype or Tintype (positive image on metal) and the negative which was printed on Albumen or Salt paper.

Many advances in photographic glass plates and printing were made in through the nineteenth century. In 1884, George Eastman developed the technology of film to replace photographic plates, leading to the technology used by film cameras today.

In 1908 Gabriel Lippmann won the Nobel Laureate in Physics for his method of reproducing colours photographically based on the phenomenon of interference, also known as the Lippmann plate.

Photography types

Black-and-white photography

All photography was originally monochrome, most of these photographs were black-and-white. Even after color film was readily available, black-and-white photography continued to dominate for decades, due to its lower cost and its "classic" photographic look. It is important to note that some monochromatic pictures are not always pure blacks and whites, but also contain other hues depending on the process. The Cyanotype process produces an image of blue and white for example. The albumen process which was used more than 150 years ago had brown tones.

Many photographers continue to produce some monochrome images. Some full color digital images are processed using a variety of techniques to create black and whites, and some cameras have even been produced to exclusively shoot monochrome.

Color photography

Color photography was explored beginning in the mid 1800s. Early 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.

One of the early methods of taking color photos was to use three cameras. Each camera would have a color filter in front of the lens. This technique provides the photographer with the three basic channels required to recreate a color image in a darkroom or processing plant. Russian photographer Sergei Mikhailovich Prokudin-Gorskii developed another technique, with three color plates taken in quick succession.

Practical application of the technique was held back by the very limited color response of early film; however, in the early 1900s, following the work of photo-chemists such as H. W. Vogel, emulsions with adequate sensitivity to green and red light at last became available.

The first color plate, Autochrome, invented by the French Lumière brothers, reached the market in 1907. It was based on a 'screen-plate' filter made of dyed dots of potato starch, and was the only color film on the market until German Agfa introduced the similar Agfacolor in 1932. In 1935, American Kodak introduced the first modern ('integrated tri-pack') color film, Kodachrome, based on three colored emulsions. This was followed in 1936 by Agfa's Agfacolor Neue. Unlike the Kodachrome tri-pack process, the color couplers in Agfacolor Neue were integral with the emulsion layers, which greatly simplified the film processing. Most modern color films, except Kodachrome, are based on the Agfacolor Neue technology. Instant color film was introduced by Polaroid in 1963.

Color photography may form images as a positive transparency, intended for use in a slide projector or as color negatives, intended for use in creating positive color enlargements on specially coated paper. The latter is now the most common form of film (non-digital) color photography owing to the introduction of automated photoprinting equipment.

Full-spectrum, ultraviolet and infrared photography

Ultraviolet and infrared films have been available for many decades and employed in a variety of photographic avenues since the 1960s. New technological trends in digital photography have opened a new direction in full spectrum photography, where careful filtering choices across the ultraviolet, visible and infrared lead to new artistic visions.

Modified digital cameras can detect some ultraviolet, all of the visible and much of the near infrared spectrum, as most digital imaging sensors are sensitive from about 350nm to 1000nm. An off-the-shelf digital camera contains an infrared hot mirror filter that blocks most of the infrared and a bit of the ultraviolet that would otherwise be detected by the sensor, narrowing the accepted range from about 400nm to 700nm. Replacing a hot mirror or infrared blocking filter with an infrared pass or a wide spectrally transmitting filter allows the camera to detect the wider spectrum light at greater sensitivity. Without the hot-mirror, the red, green and blue (or cyan, yellow and magenta) colored micro-filters placed over the sensor elements pass varying amounts of ultraviolet (blue window) and infrared (primarily red, and somewhat lesser the green and blue micro-filters).

Uses of full spectrum photography are for fine art photography, geology, forensics & law enforcement, and even some claimed use in ghost hunting.

Digital photography

Traditional photography burdened photographers working at remote locations without easy access to processing facilities, and competition from television pressured photographers to deliver images to newspapers with greater speed. Photo journalists at remote locations often carried miniature photo labs and a means of transmitting images through telephone lines. In 1981, Sony unveiled the first consumer camera to use a charge-coupled device for imaging, eliminating the need for film: the Sony Mavica. While the Mavica saved images to disk, the images were displayed on television, and the camera was not fully digital. In 1990, Kodak unveiled the DCS 100, the first commercially available digital camera. Although its high cost precluded uses other than photojournalism and professional photography, commercial digital photography was born.

Digital imaging uses an electronic image sensor to record the image as a set of electronic data rather than as chemical changes on film. The primary difference between digital and chemical photography is that chemical photography resists manipulation because it involves film and photographic paper, while digital imaging is a highly manipulative medium. This difference allows for a degree of image post-processing that is comparatively difficult in film-based photography and permits different communicative potentials and applications.

Digital point-and-shoot cameras have become widespread consumer products, outselling film cameras, and including new features such as video and audio recording. Kodak announced in January 2004 that it would no longer sell reloadable 35 mm cameras in western Europe, Canada and the United States after the end of that year. Kodak was at that time a minor player in the reloadable film cameras market. In January 2006, Nikon followed suit and announced that they will stop the production of all but two models of their film cameras: the low-end Nikon FM10, and the high-end Nikon F6. On May 25, 2006, Canon announced they will stop developing new film SLR cameras.

According to a survey made by Kodak in 2007, 75 percent of professional photographers say they will continue to use film, even though some embrace digital.

According to the U.S. survey results, more than two-thirds (68 percent) of professional photographers prefer the results of film to those of digital for certain applications including:

film’s superiority in capturing more information on medium and large format films (48 percent);
creating a traditional photographic look (48 percent);
capturing shadow and highlighting details (45 percent);
the wide exposure latitude of film (42 percent); and
archival storage (38 percent)

Because photography is popularly synonymous with truth ("The camera doesn't lie."), digital imaging has raised many ethical concerns. Many photojournalists have declared they will not crop their pictures, or are forbidden from combining elements of multiple photos to make "illustrations," passing them as real photographs. Many courts will not accept digital images as evidence because of their inherently manipulative nature and they could be completely fake, do they only take solid evidence. Today's technology has made picture editing relatively simple for even the novice photographer.

Recent changes of in-camera processing allows digital fingerprinting of RAW photos to verify against tampering of digital photos for forensics use.

Photography styles

Commercial photography

Commercial photography is probably best defined as any photography to which money exchanges hands. In this light money could be paid for the subject of the photograph or the photograph itself. Wholesale, retail, and professional uses of photography would fall under this definition. The commercial photographic world could include:

Advertising photography: photographs made to illustrate and usually sell a service or product. These images are generally done with an advertising agency, design firm or with an in-house corporate design team.
Fashion and glamour photography: This type of photography usually incorporates models. Fashion photography emphasizes the clothes or product, glamour emphasizes the model. Glamour photography is popular in advertising and in men's magazines. Models in glamour photography may be nude, but this is not always the case.
Crime Scene Photography: This type of photography consists of photographing scenes of crime such as robberies and murders. A black and white camera or an infrared camera may be used to capture specific details.
Still life photography usually depicts inanimate subject matter, typically commonplace objects which may be either natural or man-made.
Food photography can be used for editorial, packaging or advertising use. Food photography is similar to still life photography, but requires some special skills.
Editorial photography: photographs made to illustrate a story or idea within the context of a magazine. These are usually assigned by the magazine.
Photojournalism: this can be considered a subset of editorial photography. Photographs made in this context are accepted as a documentation of a news story.
Portrait and wedding photography: photographs made and sold directly to the end user of the images.
Landscape photography: photographs of different locations.
Conceptual photography: Photography that turns a concept or idea into a photograph. Even though what is depicted in the photographs are real objects, the subject is strictly abstract.
Wildlife photography that demonstrates life of the animals.
Pornography: explicit depiction of sexual subject matter, especially with the sole intention of sexually exciting the viewer using a variety of media including photography. See History of erotic photography.
Photo sharing: publishing or transfer of a user's digital photos online.

The market for photographic services demonstrates the aphorism "one picture is worth a thousand words," which has an interesting basis in the history of photography. Magazines and newspapers, companies putting up Web sites, advertising agencies and other groups pay for photography.

Many people take photographs for self-fulfillment or for commercial purposes. Organizations with a budget and a need for photography have several options: they can employ a photographer directly, organize a public competition, or obtain rights to stock photographs. Photo stock can be procured through traditional stock giants, such as Getty Images or Corbis; smaller microstock agencies, such as Fotolia; or web marketplaces, such as Cutcaster.

Photography as an art form

During the twentieth century, both fine art photography and documentary photography became accepted by the English-speaking art world and the gallery system. In the United States, a handful of photographers, including Alfred Stieglitz, Edward Steichen, John Szarkowski, F. Holland Day, and Edward Weston, spent their lives advocating for photography as a fine art. At first, fine art photographers tried to imitate painting styles. This movement is called Pictorialism, often using soft focus for a dreamy, 'romantic' look. In reaction to that, Weston, Ansel Adams, and others formed the f/64 Group to advocate 'straight photography', the photograph as a (sharply focused) thing in itself and not an imitation of something else.

The aesthetics of photography is a matter that continues to be discussed regularly, especially in artistic circles. Many artists argued that photography was the mechanical reproduction of an image. If photography is authentically art, then photography in the context of art would need redefinition, such as determining what component of a photograph makes it beautiful to the viewer. The controversy began with the earliest images "written with light"; Nicéphore Niépce, Louis Daguerre, and others among the very earliest photographers were met with acclaim, but some questioned if their work met the definitions and purposes of art.

Clive Bell in his classic essay Art states that only "significant form" can distinguish art from what is not art.

There must be some one quality without which a work of art cannot exist; possessing which, in the least degree, no work is altogether worthless. What is this quality? What quality is shared by all objects that provoke our aesthetic emotions? What quality is common to Sta. Sophia and the windows at Chartres, Mexican sculpture, a Persian bowl, Chinese carpets, Giotto's frescoes at Padua, and the masterpieces of Poussin, Piero della Francesca, and Cezanne? Only one answer seems possible - significant form. In each, lines and colors combined in a particular way, certain forms and relations of forms, stir our aesthetic emotions.|

On February 14th 2006 Sotheby’s London sold the 2001 photograph "99 Cent II Diptychon" for an unprecedented $3,346,456 to an anonymous bidder making it the most expensive of all time.

Technical photography

The camera has a long and distinguished history as a means of recording phenomena from the first use by Daguerre and Fox-Talbot, such as astronomical events (eclipses for example) and small creatures when the camera was attached to the eyepiece of microscopes (in photomicroscopy). The camera also proved useful in recording crime scenes and the scenes of accidents, one of the first uses being at the scene of the Tay Rail Bridge disaster of 1879. The set of accident photographs was used in the subsequent court of inquiry so that witnesses could identify pieces of the wreckage, and the technique is now commonplace in courts of law. The set of over 50 Tay bridge photographs are of very high quality and when scanned at high resolution, can be enlarged to show details of the failed components such as broken cast iron lugs and the tie bars which failed to hold the towers in place. They show that the bridge was badly designed, badly built and badly maintained. The methods used in analysing old photographs are known as forensic photography.

Between 1846 and 1852 Charles Brooke invented a technology for the automatic registration of instruments by photography. These instruments included barometers, thermometers, psychrometers, and magnetometers, which recorded their readings by means of an automated photographic process.

Other photographic image forming techniques

Besides the camera, other methods of forming images with light are available. For instance, a photocopy or xerography machine forms permanent images but uses the transfer of static electrical charges rather than photographic film, hence the term electrophotography. Photograms are images produced by the shadows of objects cast on the photographic paper, without the use of a camera. Objects can also be placed directly on the glass of an image scanner to produce digital pictures.

References and additional reading

Cited references

General references

Tom Ang (2002). Dictionary of Photography and Digital Imaging: The Essential Reference for the Modern Photographer. Watson-Guptill.
Freeman Patterson, Photography and The Art of Seeing, 1989, Key Porter Books, ISBN 1-55013-099-4.
The Oxford Companion to the Photograph, ed. by Robin Lenman, Oxford University Press 2005
Image Clarity: High Resolution Photography by John B. Williams, Focal Press 1990, ISBN 0-240-80033-8

External links

Center for Fine Art Photography An international, non-profit organization dedicated to promoting Photography as an Art Form
World History of Photography From The History of Art.
Daguerreotype to Digital: A Brief History of the Photographic Process From the State Library & Archives of Florida.
Judging the authenticity of Photographs: 1800s to Today Guide for collectors and historians
Rarities of the USSR photochronicles Pioneers of Soviet Photography.
Aperture A not-for-profit organisation dedicated to the advancement of photography.
"Every Picture Has a Story" - uses pictures from the Smithsonian's collections to show the development of the technology through the nineteenth century.
Shades of Light (Australian Photography 1839 - 1988) the online version of the original Shades of Light published 1998, Gael Newton, National Gallery of Australia.
The Royal Photographic Society Promotes the art and science of photography in the U.K.
PhotoQuotes.com Quotations from the world of photography.
Lens Culture International contemporary photography archives, including audio interviews with photographers