The Theatrical Luminaire

A STAGE LIGHT is referred to as fixture, an instrument or a unit, a light fitting or a lantern and as a 'luminaries' (the 'e' is silent). All terms have one thing in common. They all refer to a complete lighting 'package'- consisting of a housing, lamp (bulb), socket, reflector, electrical cord, connector and sometimes a lens, mounting clamp and colour frame.

BASIC TYPES

Luminaries designed for stage, television and film lighting applications fall into two (2) main categories; SPOTLIGHTS and FLOODLIGHTS. A third specialized category includes PROJECTORS and special lighting effects. Fixtures are typically designed to be mounted from overhead pipes, from vertical pipes or from floor stands. In this respect all fixtures incorporate a mounting yoke and usually a pipe hook clamp. The yoke and clamp allow the fixture to pan, tilt or rotate into any position and then securely lock in place. All types are fitted with colour frame clips to accept a square metal (or cardboard)'colour frame, The colour frame clips often accept other accessories including, barn doors, top hats, donuts and colour wheels.

Stage lighting fixtures range in wattage from about 300 watts to over 10,000 watts in size and capacity. Common fixtures used for stage, film and television have wattages of 300, 500, 575, 600, 750, 1000, 1200, 1500, 2000, 5000, and 10,000 watts. The wattage required depends on the amount of light needed at a specific distance and the particular characteristics of the fixture itself Needless to say, the larger the wattage, and usually the larger the fixture. In the display lighting field for example, miniature fixtures may range from 50 to 300 watts. Fixtures used for theatre lighting usually range from 500 to 2000 watts, and television and film lighting frequently employs fixtures of 1000 to 10,000 watts (or more).

LAMPS

Most modern stage lighting fixtures still use incandescent (or electric filament) lamps, in order to provide a completely 'dimmable' source. Specifically it is the tungsten halogen lamp that is used almost exclusively for stage lighting applications. This type of lamp actually has a 'self cleaning' cycle whereby the tungsten that normally blackens the outer glass bulb is redeposited back onto the filament, resulting in a more consistent light output over the life of the lamp.

Stage lighting luminaries (and lamps) are available for either 120 volt, or 240-volt lamps operation from about 12 major manufacturers, worldwide. The incandescent lamp however is largely inefficient, using most of its energy to produce heat, not light. New more efficient lamp sources are slowly being introduced to stage lighting, using discharge and other lamp technology, however inherent dimming and re-strike problems still exist with these sources.

HID and fluorescent lamps, although seldom used for theatre lighting applications, are now commonly being used for film and television lighting. These sources are much more efficient than the electric filament lamp and produce much higher lumen per Watt outputs. The use of HM and other ARC LAMPS for stage lighting however is slowly starting to develop.

FLOODLIGHTS

FLOODLIGHT fixtures are the simplest of all stage lighting fixtures, consisting simply of an enclosed light source in a box with one open side. Floods are designed to provide a wide, even. distribution of light, over a large area. Typical beam spreads range from 70-1 50 degrees. Most units come with a fixed 'beam spread' however a few units are adjustable between 'flood' and 'wide flood. Typical wattages range from 500 to 1 500 watts. Floodlights do not use lenses, however some may have a clear protective safety glass.

THE SYMETRICAL FLOOD

The single unit flood has been a standard stage lighting fixture for many 100's of years and was probably the first actual stage lighting fixture. First using oil or candles, then gas and now the electric filament lamp, this simple flood light is still the most basic of all lighting instruments. The design of the symmetrical flood has changed little over the years however, the modem symmetrical flood now uses an internal reflector, for greater efficiency.

Floodlight fixtures are particularly well suited for lighting backdrops and sky cloths. Typically, a continuous row of floodlights is arranged above and parallel to the backdrop, at a distance of 1 to 3 metres away. Floodlights are also sometimes used for the lighting of scenery or to provide large area WASHES. Less often they are used for toning and blending.

The FLOOD is available, either as a single unit, or multiple unit of 2, 3 or 4 compartments, usually connected, end-to-end. This type of fixture is used to provide a 1-4 colour wash to backdrops and large areas of scenery.
Flood fixtures are available with either a SYMMETRICAL or ASYMMETRICAL reflector design. The SYMMETRICAL ", (standard) provides regular square law illumination. That is, if the fixture is placed on the floor at a distance of 2 m., from a backdrop, the bottom of the drop will be much 'brighter than the top. A fixture with an ASYMMETRICAL reflector, will 'push' more light to the top of the drop, and provide less to the bottom. The visual result being, more even overall illumination. The fixture " and mounting distance must be carefully selected, to provided the required distribution of light and visual effect.

OPTIONS: - colour frame, safety cable, and safety mesh.

STRIPLIGHTS

Often the simple compartment floodlight is combined into multiple units connected together, forming a STRIPLIGHT. The striplight is one of the oldest stage lighting fixtures first having been developed for oil and candles and later for gas lighting. The striplight is also sometimes referred to a BATTEN or BORDER light as it often hung between the overhead masking borders.

With the introduction of the electric filament lamp it was possible to wire a number of compartment floods together, forming a long linear fixture. The striplight has changed very little in the past 100 years. The typical unit of today is 2 to 3 metres long and is wired in 3 or 4 electrical circuits. By using alternating colour filters (usually red, blue, green and sometimes amber) the striplight makes a very flexible colour wash lighting fixture.

Permanent striplights are often found installed in older theatres, auditoriums and schools. Typically several units are used, running continuously from stage left to stage right. The 'strips' are usually installed downstage, centre stage and upstage.

FOOTLIGHTS are simply striplights placed on the floor, along the downstage edge of the stage. Once a principal source of stage lighting, footlights were also often wired to provide 3 or 4 colour washes.

The modern STRIPLIGHIT typically consist of a row of MR16, PAR or double-ended halogen lamps, mounted into a single compartmented fixture approximately 2-3m. long. The modern striplight is also wired in 3 (or 4) colour circuits. Striplights are manufactured in various sizes, to use lamps with wattages of 75, 150, 300, 500 or 1000 watts each. Striplight fixtures commonly use glass or plastic coloured filters in removable colour frames. The modem striplight is used both in overhead and floor mounted applications (downright and upright)

OPTIONS: - colour frames, safety cables.

PLANO CONVEX SPOTLIGHT

The PLANO-CONVEX (or PC) spotlight is the earliest form of theatre spotlight, to use a lens. It consists of a simple box housing containing a lamp and reflector behind a piano-convex lens. Modern units range from 300 to 2000 watts. Lens diameters include 5", 6" and 8" wide. Beam spreads typically are variable from approximately 10 to 65 degrees in a single fixture.

Originally developed for a 'limelight' source in the 1870's, this fixture was adapted for the incandescent lamp in the early 1890's. The Plano-convex fixture was slowly replaced starting in the 1930's with the development of the ellipsoidal reflector fixture. The profile not only provided a 'hard defined beam edge, as did the PC fixture, but it also allowed the projection of integral framing shutters, an iris, or an etched metal pattern (gobo). The convex-convex fixture is still available today however from a number of manufacturers. They are very simple in construction and operation.

This fixture provides a circular beam pattern with a defined 'hard' outer edge.

The lamp and reflector are mounted together, and move forward or backwards, in relationship to the lens. As they move closer to the lens, the beam expands in size. As they move away from the tens, the beam becomes narrower.
Plano-convex spotlights are useful in providing ACTING AREA lighting and localized lighting to specific areas of the stage. They have no beam controls (shutters, iris, barndoors) available.

The piano-convex spotlight is generally available everywhere in the world. Strand Lighting, Selecon, ADB and others still produce a number of different models.

OPTIONS: - colour frame, barndoors, safety cable.

PROFILE SPOTLIGHT

The PROFILE spotlight is a common fixture for many stage lighting applications. The profile is available from many different manufacturers and is available in a number of different sizes and beam spreads.

Joseph Levy and Edward Kook, founders of Century Lighting, each, first introduced the profile back in 1933 giving half of their names to the new invention, Lekolite or Leko. About the same time, Kliegl Brothers introduced their profile fixture known as the 'Klieglighf. The name lekos', the name is now owned by Strand Lighting and correctly only refers to their ellipsoidal reflector products.

The profile spotlight provides a narrow, directional beam with a hard edge. It is able to provide a sharp focus of integral metal shutters, an iris or a metal projection template. The ability to project a metal etched pattern (template or gobo), makes this fixture particularly useful to the stage lighting designer.

All profile also allows focus adjustments by moving the lens tube forward or backwards. This produces an adjustable beam edge ranging from very sharp and hard to very soft. Some profiles do not allow the edges of the beams to soften sufficiently for the proper blending and sometimes the edge may need to be further softened using diffusion material.

Ellipsoidal reflector fixtures have one (1) or more lenses, usually, 4.5, 6, 8, 10 or 12" in diameter. Most profiles particularly the wider units, have two lenses. Generally, the narrower the beam spread (in degrees), the heavier the fixture will be, due to the longer lens barrel and the larger diameter lens, required.

Modem profiles spotlights have beam spreads of 5 to 50 degrees and are available in wattages of 500 to 2500 Watts.

They are available in both fixed focal length and variable focal length (zoom) models. Standard focal lengths include 5, 10, 20, 30, 40, 50, 90 degrees, and many others in between. Generally, the adjustable focal length units are less efficient, heavier and more expensive than their fixed focal length counterparts. Some modern 'zoom' profiles however do perform very well and may indeed be the choice over comparable fixed focal length units.
Up/down

Optional gobo for texture

ZOOM PROFILES with adjustable focal lengths have been available since the 1970's. A typical fixture might provide spread angles of 12-35 degrees or 25-50 degrees. No single zoom fixture is available to provide a wide zoom range of say, 10-50 deg.

OPTIONS: four shutters, gobo slot, removable lens tube, colour frame, safety cable, gobo holder, iris, lens safety mesh, gobo rotators and colour wheels.

FRESNEL SPOTLIGHT

The FRESNEL SPOTLIGHT, (pronounced: 'fren-el') provides adjustable beam spreads, from SPOT to FLOOD, (about 15-70 deg.) all in one fixture. This fixture produces a directional beam with a very soft edge (only). Fresnels are used as an efficient means of providing ACTING AREA or COLOUR WASH lighting.

All Fresnel spotlights use a single fresnel lens, deriving the name from the French physicist Augustin Fresnel, (1788-1827). A fresnel lens is simply a form of a piano-convex lens, with certain portions of glass removed, in parallel' steps'. This results is a lens that is thinner, lighter and more efficient that an equivalent PC (convex-convex) lens.

Fresnels are considerably less expensive than comparable ellipsoidal reflector fixtures, however, they do not have the ability to project a pattern or produce a sharp beam cut-off edge, as does an ellipsoidal fixture. Fresnels are very similar in size and construction to their counterparts, the Plano- convex spotlights, and the only significant difference is one uses a fresnel lens, the other a PC lens.

A fresnel lens is easy to recognize from a series of concentric rings on its surface. In addition, most Fresnel lenses have a 'stipple' etched on the backside, to further soften the beam. The higher the wattage of the fixture, the heavier the fixture weight will be, due to the larger housing and lens diameter required to withstand the extra heat generated by the lamp.
Fresnels are particularly useful in Providing COLOR WASHES to acting areas or scenery. Fresnel fixtures tend to 'flare' more than do ellipsoidal fixtures and as a result they are usually used with a barn door accessory, to help control unnecessary 'spill' light.

Fresnels are generally available in wattages of 150 to 5000 watts, and come in lens diameters of 3, 6, 8, 10 and 12". The units most often used for the stage, Include the 6" 1000 watt and the 811 2000 watt Fresnel.

OPTIONS: - colour frame, safety cable, safety mesh, and barn doors.

BEAM LIGHTS

The BEAM LIGHT (or BEAM PROJECTOR) is similar to a Fresnel fixture, without a lens. A typical Beam. Light produces a very narrow intense beam of light with a very soft edge.

Beam lights range in wattage from 500 to 2000 watts and they typically have an open circular front (10-24" in dia.). They use a parabolic reflector to provide a near parallel beam of light. In this respect, the beam light is not really a spotlight; instead, it is more of a searchlight.

They are widely used in Germany and other European countries.

Where a near parallel, intense beam of light is need, the beam projector is the fixture of choice. Designers find this fixture useful to simulate sunlight, moonlight and to provide strong motivated beams of light. The edge of the beam light is generally round, but has a very soft edge.

OPTIONS: - available: colour frame, lens safety mesh.

PAR 64 SPOTLIGHT

The PAR64 SPOTLIGHT (Parabolic Aluminised Reflector) fixtures consist of a sealed beam lamp (like an automotive headlight), in a simple metal housing. PAR fixtures are highly efficient as the; reflector, filament and lens are all optically aligned and sealed into the lamp at the factory. The beam spread of PAR fixtures is determined by the design of the lamp, not by the design of the fixture.

PAR LAMPS are available in a number of different diameters and wattages. Typically PAR64 (1000 watt) lamps are used for stage and studio lighting applications. Smaller PAR lamps are used for display and architectural applications, and include the PAR56 and the PAR38.

Where flare and a very soft beam edge is not a problem, these fixtures are particularly useful for ACTING AREA and WASH LIGHTING. They are also usually the fixtures of choice for COLOR WASH and BACK LIGHTING for entertainment productions, again, where flare and spill are not a problem.

The most common PAR fixture used in the theatre industry is the PAR64-IK (1000 watts). The fixture. is generally available in both steel and aluminium. Both black and chrome versions are available. The colour frame for a PAR64 fixture is usually 10" x 10".

This fixture uses the PAR64 lamp. This lamp has an 8" diameter lens and comes in four different standard beam spreads, and several different voltages. This 1000 watt lamp is extremely efficient at producing light - more so than an equivalent 1000 watt ellipsoidal or Fresnel fixture. The PAR64 has is the only spotlight that has an oval (not round) beam pattern. The PAR64 has a very soft beam edge and a high degree of beam' scatter' making it totally unsuitable for many lighting applications and very well suited to others.

OPTIONS: - colour frame, safety cable, lens, safety mesh, and top hat.

PAR36 PIN SPOTLIGHT

The 'pin spot', can be one of the most useful for many stage and entertainment lighting applications. Pin spots are available from a wide range of manufacturers in several different wattages.

Pin Spots are simply very narrow angle, low voltage PAR lamps, in a basic'can' type housing. These PAR lamps are manufactured for use in portable hand lanterns, for architectural lighting, marine lighting and for use as aircraft landing lights. Beam spreads are very narrow and range from approximately 5 to 10 degrees.

These PAR lamps are manufactured for use in portable hand lanterns, for architectural lighting, marine lighting and for use as aircraft landing lights. Beam spreads are very narrow and range from approximately 5 to 1 0 degrees.

All PAR lamps for pin spots are low voltage and operate on various voltages on either 5. 5, 6, 12, 24 or 29 volts. All pin spots require transformers to transform the mains voltage (120 or 240 v ac) to the proper lamp operating voltage. Usually, the transformer is incorporated into the rear of the fixture.

Pin spots can be very useful for providing accents, highlights and specials. This very low cost fixture provides an almost parallel beam of light (similar to a beam projector) can be used to provide special very'tight' lighting to actors and objects. Most pin spots can be dimmed from conventional (SCR) type dimming systems and most have colour frame clips.

FOLLOWSPOTLIGHT OR DOME

The FOLLOW SPOT is simply a narrow spotlight, used to follow or to spotlight a performer on a stage. The follow spot usually consists of a 'movable', high power fixture mounted on a stand, with an attendant operator. Typical mounting distances range from 10 to 100 metres.

Modem followspot fixtures, usually consist of a cylindrical housing, 4-6 feet in length, mounted on a telescopic stand with castered legs. They are usually fitted with a manual iris and a colour filter changer. Usually a followspot is designed to provide a hard beam edge. Controls often exist, to 'soften' the beam edge, when required.

Designers typically use the followspot fixture to provide HIGHLIGHTS to a performer or a group of performers. Modem musicals, operas, and other large productions, may frequently use from 2 to 12 followspots or more.

Followspots are traditionally mounted as high as possible at the rear of an auditorium, so as to front light the actors. Followspots are also gaining increased use in a 'bridge' position, above the stage, providing a steep@ front, back or side light to the performer.

Today, follow spotlights are available that use either incandescent or RD (discharge) type of lamps. They are manufactured for; short, medium and long throw applications and usually are mounted on stands. Various are lamps used include: CIS, MD and Xenon. They come with colour changers and usually have an iris and sometimes a dowser. Beam spreads are very narrow and typically range from approximately 1 to 10 degrees. Followspots range in size from the small 600­ watt model suitable for community theatre to the giant 2500 watt "Strong Super Trouper" used in large arena events.

OPTIONS: stand, colour changer, ballast (If required)

prepared by Andrew Kinch