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Lighting instruments are used in stage lighting to illuminate theatrical productions, rock concerts and other performances taking place in a large auditorium or stadium. They are also used to light television studios and sound stages. They can be broadly separated into two categories: floodlights, which illuminate a wide area, and spotlights, which produce a narrower, more controllable light beam. The terminology below is representative of professional stage lighting craft in the United Kingdom, Australia and the United States.
Floodlights
PAR lights
Parabolic Aluminized Reflector lights, or PAR lights, are used when a substantial amount of flat lighting is required for a scene. PAR lights resemble a car headlight, in that they possess a lens, that is an integral part of the lamp, whose position relative to the filament cannot be altered. They are frequently used in rock and roll shows, especially in combination with smoke or haze machines which make the path of the beam visible. They are also used as top lights in the theatre and for special effects.The lamp produces an intense oval pool of light with fixed focus and soft edges. The only adjustment is a knob that allows the lamp/lens unit to be rotated within its casing, thus changing the orientation of the oval. This characteristic of traditional PARs is falling into disuse with modern PARs favoring a PC based lens, which is able to produce a more controllable circular pool of light.
Strip lights
See also: Cyclorama (theater)
Scoop lights
Scoop lights or scoops are circular fixtures that do not have any lenses. They have a reflector at the back of the fixture that directs the light out of the fixture. Since they do not have any sort of lens system they are cheaper than other fixtures. However, the downside of this is that the light cannot be focused at all (even PARs allow more control than scoops). They are also called ERFs (Ellipsoidal Reflector Floodlights). Scoops are most often used to flood the stage with light from above. They are most often used as toplight hung above the stage.House lights and work lights
House lights are incandescent or fluorescent floodlights. House lights provide light for the audience before and after performances and during intermissions. Work lights provide general lighting backstage, or in the house. House lights are often controlled by dimmers, but are sometimes on simple switches. Work lights are almost always switched only. House and work lights are usually off during performances but are occasionally included in the lighting design to establish focus or emphasize plot elements.Spotlights
A spotlight is general term for any luminaire or lantern used in theatre to create a pool of light on the stage. There are many different types of spotlight which break down into three general areas:
- Fresnel lantern or PC spotlights which are small fixtures giving a soft-edged spot or pool of light.
- "Profile spotlights" which tend to be longer fixtures containing convex lenses and having a gate at their focal point which enables the insertion of gobos or irises to shape the beam of light. They give a hard edged beam most often associated in the public mind with 'spotlights'. Large versions are operated by a technician as a 'followspot' to pick out performers on the stage.
- "PAR" or '"beamlight" spotlights which throw a soft edged pool of light onto the Stage that is generally fixed and not as versatile, but can create a bright 'punch' of light to an area over a larger distance.
Fresnel lantern
A Fresnel lantern, or simply Fresnel, employs a Fresnel lens to wash light over an area of the stage. The distinctive lens has a 'stepped' appearance instead of the 'full' or 'smooth' appearance of those used in other lanterns. The resulting beam of light is wide and soft-edged, creating soft shadows, and is commonly used for back light and side light.Fresnels use a spherical reflector, with the lamp at the focus. The lamp and reflector remain a fixed unit inside the housing, and are moved back and forth to focus the light. This is done by a slider on the bottom of the lantern, or by a worm track. At very tight focus, the lanterns are the least efficient, as the least light can escape the housing. Therefore fresnels are not good for tight focus on small areas. They are most often used at medium distances from the stage for area lighting.
ERS
The Ellipsoidal Reflector Spotlight or ERS is the most abundant and important instrument type currently in use. The flexibility of the ERS allows it to fulfill the bulk of lighting roles in the theatre, from broad area lighting to tight specials; from long throws from the back of the auditorium to shin kickers on the stage. They are sometimes known by their brand names, especially the Source Four (a popular lantern from ETC) and the Leko (short for Lekolite, from Strand lighting).ERS or profiles lanterns can have many useful features. One of the most useful feature is the use of metal shutters at the focal plane of the lens to shape the beam of light. The shape of the beam is round but with the use of the shutters you can change the beam of light. Another feature is a gate, again in the focal plane for sliding in metal plates. These metal plates can have patterns cut into them, much like a stencil. These patterns are projected onto the stage etc., they are commonly known as gobos or deckles. You can also insert an iris in this position to make the beam smaller. The 3rd feature that can be built into a profile is a second lens which is used like a zoom lens, moving this lens can make the beam of light bigger or smaller.
In the UK and Australia, the term ERS is not often used. Instead, an ERS is merely considered a very good profile, or known by its brand name.
Follow spot
The follow spot is a lighting instrument that is moved, by an operator or by DMX control, to emphasize or provide extra illumination and usually to 'follow' a specific performer, especially when he or she is moving around the stage. When most people use the term "spotlight" they are referring to the follow spot. Follow spots are commonly used in musical theatre and opera to highlight the stars of a performance, but might find use in a drama to briefly focus the audience's attenion on a hand-motion or a prop; such as in a murder mystery or thriller. They are also used in sports venues, as well as many other applications.These lighting instruments come in a variety of sizes with light sources ranging from low power incandescent light bulbs to very powerful xenon arc lamps. Carbon arc lamp spots were common until the 1990s, using the arc between carbon rods as their light source. These follow spots required special installations that include high volume ventilation due to the hazardous fumes produced by the carbon arc. The current generation, xenon, has extremely high internal pressure in the lamp and thus has it's own safety concerns.
Moving lights
Moving lights or intelligent fixtures began to gain widespread acceptance in the concert industry in the early 1980's. As the digital age progressed, the cost of these fixtures reduced, and they are currently used in almost all major theatrical productions.Their principal feature is the ability to remotely control the movement and characteristics of the output beam of light. This is achieved by either moving a mirror which reflects the beam, or by moving the entire fixture, which can pan and tilt by means of a motorised yoke. They usually employ arc lamps as a light source, and generally use stepper motors connected to various internal optical devices, which manipulate the light before it escapes the fixture's front lens.
"Stage lighting instrument"