Search results
Results from the WOW.Com Content Network
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.
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.
In some old processes, the film emulsion was hardened during the process, typically before the bleach. Such a hardening bath often used aldehydes, such as formaldehyde and glutaraldehyde. In modern processing, these hardening steps are unnecessary because the film emulsion is sufficiently hardened to withstand the processing chemicals.
Advertisement for Ansco Cyko photographic paper, 1922. Photographic paper is a paper coated with a light-sensitive chemical, used for making photographic prints.When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from ...
An emulsion is a mixture of two or more liquids that are normally immiscible ... meaning they have a polar or hydrophilic (i.e., water-soluble) part and a non-polar ...
The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal.
A panchromatic emulsion is a type of photographic emulsion that is sensitive to all wavelengths of visible light, and produces a monochrome photograph—typically black and white. Most modern commercially available film is panchromatic, and the technology is usually contrasted with earlier methods that cannot register all wavelengths ...
In colour and chromogenic black-and-white photography, a similar development process is used except that the reduction of silver simultaneously oxidizes the paraphenylene colour developing agent which then takes part in the production of dye-stuffs in the emulsion by reacting with the appropriate couplers. There are three distinct processes ...