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Within a normal exposure range for film stock, for example, the reciprocity law states that the film response will be determined by the total exposure, defined as intensity × time. Therefore, the same response (for example, the optical density of the developed film) can result from reducing duration and increasing light intensity, and vice versa.
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.
For example, an emulsion rated at 250 H&D would require ten times the exposure of an emulsion rated at 2500 H&D. [7] The methods to determine the sensitivity were later modified in 1925 (in regard to the light source used) and in 1928 (regarding light source, developer and proportional factor)—this later variant was sometimes called "H&D 10".
Exposure is a combination of the length of time and the illuminance at the photosensitive material. Exposure time is controlled in a camera by shutter speed, and the illuminance depends on the lens aperture and the scene luminance. Slower shutter speeds (exposing the medium for a longer period of time), greater lens apertures (admitting more ...
If the EV is known, it can be used to select combinations of exposure time and f-number, as shown in Table 1. Each increment of 1 in exposure value corresponds to a change of one "step" (or, more commonly, one "stop") in exposure, i.e., half as much exposure, either by halving the exposure time or halving the aperture area, or a combination of ...
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 ...
Get ready for all of today's NYT 'Connections’ hints and answers for #553 on Sunday, December 15, 2024. ... Nix leads Broncos past Chiefs' reserves 38-0 and into playoffs for 1st time since 201
Traditional exposure metering and autofocus systems employ secondary sensors, whose readings are typically low-fidelity (e.g. a very small number of averaged readings from various image areas vs. fully resolved image information) and may not correspond to the actually recorded image, for example due to parallax issues, differing sensitivity ...