General Lighting Types
PLANO-CONVEX SPOTLIGHTS consist of a simple housing containing a lamp and reflector behind a plano-convex lens and provide a circular beam pattern with a sharply defined 'hard' outer edge. But the field of light is often quite uneven. Units today range from 300 to 2000 watts. Lens diameters are 5", 6" and 8". Beam spreads normally are variable from 10 to 65 degrees in a single fixture. Lamp and reflector are mounted together. Moving closer to the lens, the beam expands in size.
The Plano-Convex is the earliest form of theatre spotlight using a lens. It was first developed in the 1870's. Since the 1930's an ellipsoidal reflector fixture is used. This not only provides a 'hard' defined beam edge, as did the Plano-Convex fixture before, it also allowes shutters, iris and gobos.
ELLIPSOIDAL REFLECTOR SPOTLIGHTS have one or more lenses (normally 4.5" to 12") in diameter and are available in wattages of 500-2000 watts. They provide a narrow, directional beam with a hard edge and are able to provide a sharp focus of integral metal shutters iris or metal projection templates. The ability to project gobos makes them particularly useful for stage lighting design.
Focus adjustments are made by moving the lens tube forward or backwards, producing an adjustable beam edge ranging from very sharp to very soft.
They were first introduced back in 1933 and called 'LEKO' named after the two inventors Levy and Kook.
FRESNEL SPOTLIGHTS provide an adjustable beam from spotlight to floodlight and use one single fresnel lens. They range from 150 to 5000 watts. A fresnel lens is a regular plano-convex lens 'pushed back' in circular portions to make the glas material thinner, but keeping the optical behaviour (after the French physicist Augustin Fresnel 1788-1827.
Fresnel spotlights are less expensive but cannot produce a sharp edged beam. They are particularly useful for color washes.
PAR SPOTLIGHTS consist of a sealed beam lamp in a simple metal housing. The characteristics of the spotlight is determined with the lamp. The housing is actually only holding the lamp and any color filters.
Typically used PAR spotlights are the PAR64, PAR56 and PAR38.
PAR spotlights are used for the acting area, as wash lights and back lights.
PIN SPOTLIGHTS are low voltage PAR lamps that provide a very narrow lighting angle. Voltage ranges from 5.5volts to 28 volts. Pin spots always require power supply voltage transformers.
BEAM PROJECTORS are similar to fresnel fixtures, but without a lens. They use a parabolic reflector to provide the very narrow (nearly parallel) beam and range from 500 to 2000 watts.
FOLLOW SPOTS are any narrow spotlights, used to follow a performer on stage. Very specialized units are available using extra high output lamps (CIS, HID and Xenon). Beam spreads range from approximately 1 to 10 degrees. They range from 600 watt for small applications to 2500 watt (Super Trouper).
FLOODLIGHTS consist simply of a housing with any enclosed light source. Floodlights are designed to provide a wide and even distribution of light over a large area. They range from 500 to 1500 watts.
STRIPLIGHTS are multiple floodlight units connected together to form a so-called batten light or border light between overhead masking borders. Alternating color filters are usually used to create a very flexible color wash lighting fixture.
FOOTLIGHTS are striplights placed on the floor, along the downstage edge of the stage.
LINNEBACH PROJECTORS are the simplest and first projectors used for scenic projection. They were developed in the early 1900's. No lens but only a point light source is used and the image has a very soft definition.
OPTICAL PROJECTORS, using lenses and full projection techniques, are very common today in stage lighting. For large projections often the 'PANI' projector is used (Austrian company Ludwig Pani). Stage projectors range from 2000 to 10,000 watts.
AUTOMATED FIXTURES are available in two basis types: moving fixtures or fix fixtures with moving mirrors.
Companies manufacturing automated fixtures are 'Vari*Lite', 'Clay Paky', 'Hi-End Systems', 'Martin' and others.