Photographic exposure

Photovoltaic cells. The selenium photographic exposure meter has already been mentioned it goes back to Adams and Day s (1877) study of selenium, was further developed by Charles Fritt in 1885 and finally became a commercial product in the 1930s, in competition with a device based on cuprous oxide. This meter was efficient enough for photographic purposes but would not have been acceptable as an electric generator. 

The lead compounds PbS, PbSe, PbTe are narrow-gap semiconductors that have been widely investigated for infrared detectors, diode lasers, and thermo-photovoltaic energy converters. Their photoconductive effect has been utilized in photoelectric cells, e.g., PbS in photographic exposure meters. Integrated photonic devices have been fabricated by their heteroepitaxial growth on Si or III-V semiconductors. 

Pure PbS is a p-type semiconductor when S-rich, and an n-type when Pb-rich (the non-stoichiometric nature of solids is discussed in Section 27.2). It exhibits photoconductivity and has applications in photoconductive cells, transistors and photographic exposure meters. 

Aerial night reconnaissance photography was started by the British in 1918 and went through numerous phases because of the difficult tie-in of illumination and camera action. The historical aspects of the development, with emphasis on the proUem of relating the interval of highest light emission with photographic exposure, are related in a BuWeps report. ... 

An important property of Se is its ability to convert light into electricity, and the element is used in photoelectric cells, photographic exposure meters and photocopiers (see Box 16.1). A major use of selenium is in the glass industry. It is used to counteract the green tint caused by iron impurities in soda-lime silica glasses, and is also added to architectural plate glass to reduce solar heat transmission. 

Exposure meter (1891) n. A device for indicating correct photographic exposure under varying conditions of illumination. 

Processing Chemical means by which photographic film and paper are treated after photographic exposure to produce a negative or positive image. 

Cinematographe (Auguste and Louis Lumiere) The Lumiere brothers combined motion-picture camera, printer, and projector helps establish the movie business. Using a very fine-grained silver-halide gelatin emulsion, they cut photographic exposure time down to about one minute. 

Jones, L. A., and Condit, H. R., Sunlight and skylight as determinants of photographic exposure. I. Luminous density as determined by solar altitude and atmospheric conditions. 

Several photographic exposures are taken of the detonation front, the shock waves in the water, and the expanding tube-water interface (or bubble-water interface if the tube is absent). The optical data, shown schematically in Figure 2.12. are used to infer detonation velocity, detonation pressure (C-J states), and the release isentrope of the detonation products. A collection of aquarium test data is available in the data volume entitled Los Alamos Explosives Performance Data and on the CD-ROM. An animation of a NOBEL calculation of a PBX-9502 aquarium test is on the CD-ROM in the /MOVIE/AQUAR.MVE directory. 

Figure 2.23 The aquarium test for X0233. Two photographic exposures taken with the image intensifier camera. The shock wave in the water and the interface between the...

Radioactivity was discovered by Antoine-Hemi Becquerel when he found that uranium causes a photographic exposure in the absence of light. 

Figure 7.2 Photographic exposure (1/1000 s) of corona and atmospheric chemical plasma discharges between an electrode and ground plane. (Source Enercon Industries Inc.)...

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