Search results
Results from the WOW.Com Content Network
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 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.
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.
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 ...
The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinner than common window glass. They were heavily used in the late 19th century. With the spread of photographic film, the use of plates declined through the 20th.
Silpat sheet – This is made of silicone and fibreglass; textured and provides air pockets to prevent damage from the capillary application; it does not traumatize the emulsion side of the glass. Secondary support – This method is used for glass plates broken into many pieces or over 5 by 7 inches (130 mm × 180 mm) in size.
It requires an exposure in the camera that lasts at least eight hours and probably several days. 1834 – Hércules Florence, a French-Brazilian painter and the isolate inventor of photography in Brazil, coined the word photographie for his technique, at least four years before John Herschel coined the English word photography. [9]