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For example, for a given film, if a light meter indicates a required EV of 5 and the photographer sets the aperture to f/11, then ordinarily a 4-second exposure would be required; a reciprocity correction factor of 1.5 would require the exposure to be extended to 6 seconds for the same result. Reciprocity failure generally becomes significant ...
Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper.The paper is exposed to a photographic negative, a positive transparency (or slide), or a digital image file projected using an enlarger or digital exposure unit such as a LightJet or Minilab printer.
Because the image emerges as a direct result of exposure to light, without the aid of a developing solution, an albumen print may be said to be a printed rather than a developed photograph. The table salt (sodium chloride) in the albumen emulsion forms silver chloride when in contact with silver nitrate. Silver chloride is unstable when exposed ...
Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography , it consists of silver halide crystals dispersed in gelatin . The emulsion is usually coated onto a substrate of glass , films (of cellulose nitrate , cellulose acetate or polyester ), paper, or fabric.
A developable photographic latent image forms when crystals of silver halide in an emulsion layer are exposed to light. The initial nucleation phase is chemically and thermodynamically unstable; it is thus temperature sensitive, and involves the production of one, or very few silver atoms as sub-latent image specks in each silver halide crystal.
It was invented by French scientist Gabriel Lippmann in 1891 and consists of first focusing an image onto a light-sensitive plate, placing the emulsion in contact with a mirror (originally liquid mercury) during the exposure to introduce interference, chemically developing the plate, inverting the plate and painting the glass black, and finally ...
Photographic emulsions were originally coated on thin glass plates for imaging with electron microscopes, which provided a more rigid, stable and flatter plane compared to plastic films. [7] Beginning in the 1970s, high-contrast, fine grain emulsions coated on thicker plastic films manufactured by Kodak, Ilford and DuPont replaced glass plates.
Contact print of a photo film cut in pieces, used for reviewing and selecting images for the final print. Photo by Paolo Monti, 1975. Contact printing is a simple and inexpensive process. Its simplicity avails itself to those who may want to try darkroom processing without buying an enlarger.