Photography is a word derived from the Greek words photos ("light") and graphein ("to draw")
The word was first used by the scientist Sir John F.W. Herschel in 1839. It is a method of recording images by the action of light, or related radiation, on a sensitive material.
Alhazen (Ibn Al-Haytham), a great authority on optics in the Middle Ages who lived around 1000AD, invented the first pinhole camera, (also called the Camera Obscura} and was able to explain why the images were upside down.
The first casual reference to the optic laws that made pinhole cameras possible, was observed and noted by Aristotle around 330 BC, who questioned why the sun could make a circular image when it shined through a square hole.
As a means of visual communication and expression, photography has distinct aesthetic capabilities. In order to understand them, one must first understand the characteristics of the process itself. One of the most important characteristics 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 (but reversed) image usually called a negative is formed, and the image becomes visible by development and permanent by fixing with sodium thiosulfate, called “hypo.” With modern materials, the processing may take place immediately or may be delayed for weeks or months.
The essential elements of the image are usually established immediately at the time of exposure. This characteristic is unique to photography and sets it apart from other ways of picture making. 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 photograph possesses, in the popular mind, such apparent accuracy that the adage “the camera does not lie” has become an accepted, if erroneous, cliché.
This understanding of photography’s supposed objectivity has dominated evaluations of its role in the arts. In the early part of its history, photography was sometimes belittled as a mechanical art because of its dependence on technology. In truth, however, photography is not the automatic process that is implied by the use of a camera. Although the camera usually limits the photographer to depicting existing objects rather than imaginary or interpretive views, the skilled photographer can 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 photographer also may set up a completely artificial scene to photograph.