Invention of photography

18 février 2015

Photography is the science, art and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film.

Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure.

When you photograph people in color, you photograph their clothes. But when you photograph people in Black and white, you photograph their souls!

Ted Grant

With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in a digital image file for subsequent display or processing.

Photography is employed in many fields of science, manufacturing  and business, as well as its more direct uses for art, hobby, and mass communication.

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.

The tones and contrast between light and dark areas define black-and-white photography.

It is important to note that monochromatic pictures are not necessarily composed of pure blacks, whites, and intermediate shades of gray, but can involve shades of one particular hue depending on the process. The cyanotype process, for example, produces an image composed of blue tones. The albumen print process, first used more than 150 years ago, produces brownish tones.

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 (normal, long focus, wide angle, telephoto, 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.

Some full-color digital images are processed using a variety of techniques to create black-and-white results, and some manufacturers produce digital cameras that exclusively shoot monochrome.

Monochrome printing or electronic display can be used to salvage certain photographs taken in color which are unsatisfactory in their original form; sometimes when presented as black-and-white or single-color-toned images they are found to be more effective.