What is Photography?

Photography is the process, activity and art of creating still pictures by recording radiation on a radiation-sensitive medium, such as a photographic film, or electronic image sensors.
Photography uses foremost radiation in the UV, visible and near-IR spectrum. For common purposes the term light is used instead of radiation.
Light reflected or emitted from objects form a real image on a light sensitive area (film or plate) or a FPA pixel array sensor by means of a pin hole or lens in a device known as a camera during a timed exposure.
The result on film or plate is a latent image, subsequently developed into a visual image (negative or diapositive).
An image on paper base is known as a print. The result on the FPA pixel array sensor is an electrical charge at each pixel which is electronically processed and stored in a computer (raster)-image file for subsequent display or processing.
Photography has many uses for business, science, manufacturing (f.i. Photolithography), art, and recreational purposes.Photography is the result of combining several technical discoveries. Long before the first photographs were made, Chinese philosopher Mo Di and Greek mathematicians Aristotle and Euclid described a pinhole camera in the 5th and 4th centuries BC.

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1. Monochrome photography

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, often because of the established archival permanence of well processed silver halide based materials.
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.

2. Color photography

Color photography was explored beginning in the mid-19th century. 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.
Early color photograph taken by Prokudin-Gorskii (1915).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 20th century, following the work of photo-chemists such as H. W. Vogel, emulsions with adequate sensitivity to green and red light at last became available

3. Full spectrum 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 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.[20] 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).

4. 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 1991, Kodak unveiled the DCS 100, the first commercially available digital single lens reflex camera. Although its high cost precluded uses other than photojournalism and professional photography, commercial digital photography was born.



Sources: Wikipedia.