Processes of photography

Art And Craft 2378 Hits > 2010-05-28 07:32:06


digital camera, Canon Ixus
Processes of photography


Photography is the process, activity and art of creating still or moving pictures by recording radiation on a radiation-sensitive medium, such as a photographic film, or an electronic sensor. Light patterns reflected or emitted from objects activate a sensitive chemical or electronic sensor 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. Lens and mounting of a large-format camera. A historic camera: the Contax S of 1949 — the first pentaprism SLR. Nikon F of 1959 — the first 35mm film system camera. Late Production Minox B camera with later style "honeycomb" selenium light meter

A portable folding reflector positioned to "bounce" sunlight onto a model. The word "photograph" was coined in 1839 by Sir John Herschel and is based on the Greek (photos) "light" and (graphé) "representation by means of lines" or "drawing", together meaning "drawing with light".Traditionally, the products of photography have been called negatives and photographs, commonly shortened to photos.

 

Black-and-white


All photography was originally monochrome, or 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, first used more than 150 years ago, produces 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 manufacturers produce digital cameras that exclusively shoot monochrome.


 


Color


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 commercially successful color process, the Autochrome, invented by the French Lumière brothers, reached the market in 1907. It was based on a 'screen-plate' filter made of dyed grains of potato starch, and was one of many additive color screen products available between the 1890s and the 1950s. A later example of the additive screen process was the German Agfacolor introduced in 1932. In 1935, American Kodak introduced the first modern ('integrated tri-pack') color film which was developed by two musicians Leopold Mannes and Leopold Godowsky ("Man" and "God") working with the Kodak Research Labs. It was Kodachrome, based on multiple layered silver gelatin emulsions that were each sensitized to one of the three additive colors—red, green, and blue. The cyan, magenta, and yellow dyes were created in those layers by adding color couplers during processing. This was followed in 1936 by Agfa's Agfacolor Neu. Unlike the Kodachrome tri-pack process, the color couplers in Agfacolor Neu were incorporated into the emulsion layers during manufacture, which greatly simplified the film processing. Most modern color films, except Kodachrome, use such incorporated-coupler techniques, though since the 1970s nearly all have used a technique developed by Kodak to accomplish this, rather than the original Agfa method. 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


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 350 nm to 1000 nm. 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 400 nm to 700 nm. 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.Though most new camera designs are now digital, a new 6x6cm/6x7cm medium format film camera was introduced in 2008 in a cooperation between Fuji and Voigtländer.



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)


Digital imaging has raised many ethical concerns because of the ease of manipulating digital photographs in post processing. 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. Today's technology has made picture editing relatively simple for even the novice photographer. However, recent changes of in-camera processing allows digital fingerprinting of RAW photos to verify against tampering of digital photos for forensics use.



Camera phones, combined with sites like Flickr, have led to a new kind of social photography.

 



 






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