Search results
Results from the WOW.Com Content Network
Note that the times are approximate, and vary between different films and ASA numbers, but the table shows in general how the exposure time is adjusted. In photography , reciprocity is the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material.
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.
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 ...
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.
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 ...
The Federal Reserve Board in Washington and its 12 regional reserve banks across the US employed about 24,000 people last year. The vast majority — more than 86% — of staff work out of the ...
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.
VILNIUS (Reuters) -Lithuania has found no sign that the crash on Monday of a DHL cargo plane was caused by sabotage, and believes technical issues were a more likely explanation, officials said on ...