Components Stage lighting instrument

1 components

1.1 housing
1.2 lens or opening
1.3 reflector
1.4 yoke
1.5 attachment apparatus
1.6 lamp or arc source
1.7 accessories

components

see picture @ top right physical location of components.

stage lighting instruments have following components:

housing

the lamp housing metal or plastic container serves body entire instrument , prevents light spilling in unwanted directions. comprises of exterior of fixture except lens or opening. housing may designed specific elements reduce heat , increase efficiency of lamp. older instruments made rolled , machined steel or aluminum. advent of source four, many lighting instruments being made die cast metal. die casting allows 1 single, light-weight body more economical produce , use. first lantern make use of die castings strand pattern 23 designed fred bentham in 1953, small mirror spot enjoyed 30-year production run , found way many british schools, halls , theaters. instruments made plastic, such selecon pacific.

lens or opening

optics of altman 1000q followspot. left right: lamp, ellipsoidal reflector, shutter/iris assembly, fixed lens, variable lens.

the opening of samad gap in housing beam of light intended come. many fixtures use lens control beam of light, though some, such border or cyclorama lights, not have lenses or optics other reflector. lens , reflector, along other beam-altering devices both considered part of optics system.

reflector

the reflector affects quality , directionality of light output. reflector located behind or around light source in such way direct more light towards lens or opening. each unit has characteristic reflector, used in conjunction lens (or lack thereof) create desired effect. ellipsoidal reflector has lamp set @ 1 focus point of ellipsoid-shaped reflector bounces light , focuses @ second focus point of ellipse. focuses beam of light tight beam. ellipsoidal reflectors used tight, focusable spots, although can used floodlights, such in scoops (see below). parabolic reflector has lamp set @ focus point of parabola-shaped reflector bounces light in parallel beams away reflector. there no point @ light converges, light unfocusable. parabolic reflectors used lights intended provide unfocused wash, such par cans.

reflectors can used selectively reduce or eliminate unwanted thermal emission. incandescent lamps produce light through heating of filament, while arc lamps produce light through heating , ionization of gas. in either case, heat emitted lamp infrared light. thermal energy projected onto stage visible light, , thousands of watts of incandescent lighting can uncomfortably hot actors on stage. specially designed reflectors able absorb , dissipate infrared @ fixture before visible light reaches stage.

yoke

most instruments suspended or supported u-shaped yoke, fixed @ 2 points sides of instrument, providing axis of rotation. base of yoke typically single bolt around yoke can rotated, providing second axis of rotation. combined together, these 2 axis allow fixture point anywhere in spherical range of motion encircling yoke.

the yoke connected pipe or batten 1 of clamps mentioned below. may affixed deck floor mounts, or attached set stage screw.

some yokes motorized, allowing remote control systems change fixture pointing during show.

attachment apparatus

c-clamps hook clamps use threaded bolt attach pipe or batten , hold instrument secure. once secured, fixture can panned , tilted using adjustment knobs on yoke , clamp. in addition, safety cables (a loop of aircraft cable terminated carabiners) used support lighting instrument in case clamp fails. side arm metal pole bolted instrument clamp on end. enables instrument hung side of electric opposed below it.

lamp or arc source

most theatrical lamps tungsten-halogen (or quartz-halogen), improvement on original incandescent design used halogen gas instead of inert gas. fluorescent lights used other work lights (see below). although far more efficient, cannot dimmed (run @ less full power) without using specialized dimmers, cannot dim low levels, not produce light single point or concentrated area, , have warm-up period during emit no light or intermittently. high-intensity discharge lamps (or hid lamps) common bright light output required, example in large follow spots, hmi (hydrargyrum medium-arc iodide) floods, , modern automated fixtures. because these types of lamps cannot electrically dimmed, dimming done mechanical dousers or shutters physically block portions of lamp decrease output. specially-designed fittings use light-emitting diodes (leds) light source. leds ideal intense unfocused light source required, such lighting cyclorama.

accessories

conventional (non-intelligent) fixtures designed accept number of different accessories intended assist in modification of output. common, found on stage lights, gel frame holder. gel frame holder intended hold gel, mounted in cardboard or metal gel frames. other common accessories include gobo holders or rotators, iris holders, donuts, barn doors , color scrollers.