the branch of science and engineering concerned with the use of radiant energy containing visible wavelengths (light). It investigates principles and develops methods for generating and spatially redistributing light, measuring light characteristics, and converting light into other forms of energy. It also deals with the technological development and design of light sources, lighting, irradiating, and signaling instruments and devices, and control systems for light sources. It studies problems related to the setting of standards, the design, and the arrangement and operation of illuminating engineering installations. In addition, illuminating engineering is concerned with the effects of natural and artificial light on substances and organisms. The term “illuminating engineering” in its present broad sense first appeared in scientific and technical literature in the 1920’s. Prior to that time, the term was understood to include only problems of lighting proper.
Illuminating engineering grew out of developments in physical and geometrical optics, physiology, and the study of electricity and magnetism. Its emergence owes much to the work of I. Newton, J. Lambert, M. V. Lomonosov, T. Young, V. V. Pe-trov, J. Purkinje, H. Helmholtz, and other physicists, physiologists, and electrical engineers. A major contribution to illuminating engineering was made in the early 18th century by P. Bouguer, who formulated the fundamentals of photometry in his Optical Treatise on Gradation of Light. The transition to electrical light sources was a landmark in the development of illuminating engineering. In 1872, A. N. Lodygin invented the incandescent lamp, which was later perfected by T. Edison. In 1876, P. N. Iablochkov invented the carbon arc lamp (without a regulator for adjusting the distance between electrodes), known as the Iablochkov (Jablochkov) light. Subsequent progress in illuminating engineering was associated with the development of fluorescent lamps, high-pressure gas-discharge lamps, and halogen-filled incandescent lamps. In turn, the work done in illuminating engineering furthered the development of electronics and led to the emergence of quantum electronics.
In illuminating engineering, installations (and corresponding lighting devices) are classified according to the field of light utilization as lighting, irradiating, or signaling installations. Lighting installations provide the necessary conditions for visual reception (seeing), through which man receives approximately 90 percent of the information about his physical surroundings. In the USSR, artificial lighting consumes 10–12 percent of the total electric energy generated (650 million lamps). In the United States, the corresponding figure is 18 percent.
Irradiating installations are used to produce nonvisible effects on humans, animals, and plants. They can also be used in diverse industrial processes. The irradiation of organisms by ultraviolet, visible, or infrared light improves (or supports) such vitally important morphological and functional processes as metabolism, sanguification, the regulation of cardiovascular activity, and, in the case of plants, photosynthesis. Irradiation can also increase the resistance of an organism to disease. The USSR occupies a leading position in the utilization of ultraviolet radiation in children’s hospitals and institutions, which are located in the northern part of the country. Bactericidal irradiation has a significant hygienic effect, killing harmful bacteria and reducing the incidence of disease by a factor of 1.5–2. Ultraviolet irradiation is used to disinfect water and food products. Irradiation installations are now being used with success in physical therapy (Kvarts, Soluks). Irradiation installations used in agriculture have had significant economic results. Ultraviolet irradiation of cattle and poultry has increased productivity, as measured by increased milk and egg yields and weight gain, by 7–15 percent. Artificial light is also used in the commercial growing of vegetables, berries, and fruits in hothouses. Irradiation installations are also used in photolithography, in the drying of paint and varnish coatings, and in photochemical and other technological processes.
Signaling installations are used for transmitting coded information in the form of signals produced by such signaling devices as traffic lights, lighthouses, running lights, and landing lights. The signals are received by the eye or by other radiation receptors, such as photoelectric cells.
Measurements of light characteristics and the determination of standards for lighting installations are other important areas of illuminating engineering.
In addition to its traditional concerns, modern illuminating engineering also deals with such problems as the creation of comfortable visual environments that produce a complex of visual, morphological and functional, and hygienic effects and the utilization of light as an effective and profitable means of agricultural production. Modern illuminating engineering is also concerned with the technological applications of light, the development of light sources in which processes of chemilu-minescence and electroluminescence are realized, and semiconductor and radioisotope materials are used.
Soviet illuminating engineering is among the world’s leaders. Important contributions to the development of the Soviet school have come from S. I. Vavilov (luminescence, effects of light), M. A. Shatelen (photometry, standards for lighting installations), S. O. Maizel’ (physical principles of vision), A. A. Gershun (theoretical photometry, calculations of the light field), P. M. Tikhodeev (standards for lighting installations, photometric standards and measurements), V. V. Meshkov (principles for setting standards and designing lighting installations), and N. M. Gusev and V. A. Drozdov (illuminating engineering in construction work). In the USSR, illuminating engineering research and development is conducted by a number of scientific and educational centers and planning institutes, including the All-Union Scientific Research, Design and Technological Illuminating Engineering Institute (VNISI, Moscow), the All-Union Scientific Research, Design and Construction, and Technological Institute of Light Sources (VNIIIS, Saransk), the illuminating engineering laboratories of the Scientific Research Institute for Labor Protection of the All-Union Central Council of Trade Unions (Leningrad, Invanovo, and elsewhere), and the illuminating engineering department of the Moscow Power Engineering Institute.
The USSR is a member of the International Commission on Illumination and the International Electrotechnical Commission. Information on problems of illuminating engineering is published in such journals as Svetotekhnika (Illuminating Engineering, founded 1932), Light and Lighting and Environmental Design (London, 1908), Lux (Paris, 1928), and Lighting Design and Application (New York, 1906).
REFERENCESSpravochnaia kniga po svetotekhnike [fascs. 1–2]. Moscow, 1956–58.
Meshkov, V. V. Osnovy svetotekhniki, parts 1–2. Moscow-Leningrad, 1957–61.
Rokhlin, G. N. Gazorazriadnye istochniki sveta. Moscow-Leningrad, 1966.
Tikhodeev, P. M. Svelovye izmereniia v svetotekhnike, 2nd ed. Moscow-Leningrad, 1962.
Gutorov, M. M. Osnovy svetotekhniki i istochniki sveta. Moscow, 1968.
Aizenberg, Iu. B., and V. F. Efimkina. Osvetitel’nye pribory s liuminestsentnymi lampami. Moscow, 1968.
Meshkov, V. V., and M. M. Epaneshnikov. Osvetitel’nye ustanovki. Moscow, 1972.
Knorring, G. M. Svetotekhnicheskie raschety v ustanov-kakh iskusstvennogo osveshcheniia. [Leningrad] 1973.
Gusev, N. M., and V. G. Makarevich. Svetovaia arkhitektura. Moscow, 1973.
In the shooting of a film, illuminating engineering includes the development and application of light sources and lighting devices for illuminating the shooting process and of lighting systems and screens for special types of shooting (special effects). It is also concerned with the development and use of light filters and of photometric apparatus for investigating the properties of photosensitive materials, the parameters of light sources and lighting devices, and the lighting conditions during filming. Problems of film exposure and certain artistic and creative problems encountered in filming, especially when shooting, for example, in fog or underwater, can be resolved by the methods of illuminating engineering.
Of the artificial light sources used in filming, incandescent lamps have been found to be most convenient. They are of diverse types and power ratings, but they all have the same color temperature (Tcol ≈ 3200°-3250°K). Incandescent projector-type lamps, whose filaments are concentrated in a small area, have power ratings of 0.15–20 kilowatts (kW), luminous efficiencies of 25–29 lumens per watt (lm/W), and luminances of ∼ 107 candelas per sq m (cd/m2). Among the more promising projector-type lamps are the quartz-halogen incandescent lamps, which have constant operating characteristics and are simple to connect and operate. Reflector lamps and floodlights are also used. In powerful floodlight and spotlight installations, open, high-intensity carbon arc lamps with luminances of 5–7 × 108 cd/m2 are used. Of the gas-discharge light sources, direct-current xenon gas-discharge lamps and metal-halogen lamps are the two principal types in current use. Light from the xenon lamps has a constant spectral composition and comes closest to imitating average daylight (Tcol ≈ 5700°K); the luminance of xenon lamps is 2–10 × 108 cd/m2, and the luminous efficiency 25–45 lm/W. The metal-halogen lamps possess high luminous efficiency (70–100 lm/W) and reproduce colors satisfactorily. They are manufactured with Tcol values of 6000° and 3200°K.
Floodlights and spotlights equipped with Fresnel lenses (diameters 100–270 mm) and incandescent lamps are used as lighting devices in filming. The luminous intensity of the lamps and the angle of dispersion of the light can be changed within wide limits by defocusing. Filming spotlights and floodlights with Fresnel lenses and carbon arcs have a higher luminous intensity than the type with incandescent lamps but are less convenient to handle. Cinematographic lighting devices with quartz-halogen incandescent lamps are the most convenient to handle and the most diverse in characteristics.
In filming work, lighting is controlled with exposure meters having a wide (20° or more) or a narrow (0.5°–1.5°) acceptance angle and with luxmeters that measure the illuminance of the main object being filmed, for example, an actor’s face, which is assumed to be a diffusely reflecting object with a reflection coefficient of approximately 0.3. The quality of color reproduction is evaluated with the aid of color measuring devices (colorimeters); for individual areas of a frame, the evaluation is made with color brightness meters for frame details (with a field of ∼ 1 °). Changes in the spectral composition of light can be achieved by equipping lighting devices with light filters (“compensating” or “effect” filters) of the absorption or interference type.
With respect to film printing, illuminating engineering is concerned with the development of lighting systems and photometric instruments for diverse motion-picture film printers. Here, light sources are, in most cases, quartz-halogen incandescent lamps. Lighting at the negative holder is controlled by photometric instruments, with due regard for the spectral sensitivity of the print.
In the projection of films, illuminating engineering is concerned with such tasks as increasing the quality of film showings, lowering the costs of film production, and simplifying the servicing of motion-picture projection units. To accomplish these goals, special light sources for projection equipment and lighting systems with accompanying components are being developed, as are screens and photometric instruments. In addition, the conditions that ensure satisfactory viewing are being studied. These conditions, which include magnitude of projection luminance, uniformity of projection, tolerance for flare, and quality of color reproduction, must be determined for such various types of projection as standard, daylight, and stereoscopic.
The luminance for cinematographic projections on a screen in a darkened hall has been standardized at 35 cd/m2, which applies when the projector shutter is operating without a film. This luminance is used to determine the proper luminous flux of the projector for a given hall and a given screen. In professional cinematography, projectors have luminous fluxes of 150 to 30,000 lm or more. In projectors with small luminous fluxes (up to 600 lm in 60-mm units and 1,300 lm in 35-mm units), picture-projection incandescent lamps are used. These lamps, which have a high overall luminance (∼ 3 × 107 cd/m2, usually quartz-halogen), are often combined into a single unit with an ellipsoidal reflector. Projectors with higher luminous flux levels (2,500–30,000 lm) are usually equipped with illuminators having, in most cases, xenon lamps (power ratings 1–10 kW).
Measurements of projection luminance and uniformity are usually made with brightness meters at various points in the viewing hall; the illuminance of the screen is measured with a luxmeter. Reflectometers or sets of working standards of luminance coefficients are used to monitor screens. The chromatic-ity of motion-picture projections is measured by three-color photoelectric colorimeters or, less accurately, by two-color instruments that measure color temperature. Control of light sources and optical elements is achieved through special photometric instruments.
REFERENCESBaranov, G. S., V. G. Pell’, and A. A. Sakharov. Spravochnik po lekhnike kinos”emki. Moscow, 1959.
Golostenov, G. A., and T. V. Derbisher. Istochniki sveta kinoproektorov. Moscow, 1968.
Golostenov, G. A., and T. V. Derbisher. Svetotekhnicheskii kontrol’ kinoustanovok. Moscow, 1971.
Kosmatov, L. V. Svet v inter’ere. Moscow, 1973.
Goldovskii, E. M. Vvedenie v kinotekhniku. Moscow, 1974.
Structural illuminating engineering was established as a separate area of specialization during the 1950’s. The field developed as a result of the large volume of industrial construction, the improvement of existing and the creation of new light-transmitting materials and structures, and the development and widespread use of new types of light sources.
Problems in structural illuminating engineering are solved through theoretical calculations based on established physical regularities and through evaluations of the illuminating-engineering characteristics of rooms with the aid of models. They are also solved through laboratory tests of light-transmitting building materials and structural components of windows, skylights, and sun-screening units, and through observations and measurements made at the structures themselves. Photometric, particularly colorimetric, techniques are widely used in structural illuminating engineering. Simulation installations of the sky dome type are constructed to facilitate studies of the illuminating-engineering characteristics of structural components and building models. A similar installation consists of a photometric sphere, with a model of the natural sky on the inner surface, and a light-receiving chamber. The sample being tested is mounted in an aperture of the chamber.
Structural illuminating engineering finds numerous applications in the design and construction of, for example, cities, man-made industrial and agricultural buildings, picture galleries, museums, monuments, and exhibition pavilions. Structural illuminating engineering has great importance for production enterprises because optimal quantitative and qualitative lighting characteristics increase labor productivity and the quality of work. Lighting also contributes to productivity in animal husbandry and horticulture.
Prospects for development in structural illuminating engineering are related to improved standards for natural and artificial lighting. These standards take into account the complex ways in which the light and color environment affects architectural and aesthetic sensibilities and the efficiency and health of persons. Future developments will also be affected by the solution of problems of parameter optimization for structures and lighting installations in accordance with requirements that determine the operational properties of buildings and the microclimate of rooms. These requirements pertain not only to illuminating engineering but also to heat engineering, structure strength, acoustics, and aerodynamics.
REFERENCESGusev, N. M., and N. N. Kireev. Osveshchenie promyshlennykh zdanii. Moscow, 1968.
Stroitel’naia svetotekhnika [fascs. 1–4]. Moscow, 1969–74.
Drozdov, V. A. Fonari i okna promyshlennykh zdanii. Moscow, 1972.
M. I. KRASNOV