Parabolic aluminized reflector light
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A Parabolic Aluminized Reflector light, or PAR light, is a stage lighting fixture widely used in theatre, concerts and motion picture production when a substantial amount of flat lighting is required for a scene.
They are nearly identical in principle to the old-style sealed beam automobile headlight or, when used in grid arrays, to stadium lighting. They are frequently used in patterns of multiple lights such as 3 by 3 (known as a "nine light") when large areas are to be lighted.
In situations where sunlight or other specular light is available, a white foam reflector is often used to accomplish the same effect as a PAR array.
Construction
PAR lights possess a lens, that is an integral part of the lamp, the position of which cannot be altered relative to the filament. A notable exception is ETC's Source Four PAR, which uses the same halogen lamp as their Source Four ERS. In this case, the lens is a separate piece from the lamp. The relative position of lamp and lens remains unalterable. In PAR 64s, Raylite reflectors and two pin base lamps are often used as a cheaper alternative as the lamp is replaced but the reflector remains. Lamps such as the 500 watt A1/244 can be as much as half the price of the sealed beam units. Narrow, medium and wide Raylite refectors are quite readily available. The 2 blade (pin)Mogul lamp connector need not be replaced - this is integral to the Raylite reflector, Although some Raylite reflectors have "tails" which then require connection to the mains flex with the use of a ceramic connector block (ideally fixed to the cans body). http://www.jamesthomas.co.uk/pdf-uk/par64.pdf
Effects
The sealed beam lamp produces an intense oval pool of light with 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. With some models this control is via the mogul ceramic connector which connects directly to the Mogul prongs of the lamp. This is a fairly hazardous method of adjusting the beam. There are a number of alternatives such as the PARsafe, of which there are many variants, and the James Thomas lamp adjuster which effectively seals the rear of the can and provides an external control to adjust the lamp. The type of lens may be changed, options include extra-wide flood (XWFL), wide flood (WFL), medium flood (MFL), narrow spot (NSP), and very narrow spot (VNSP).
These types of instruments come in varying diameters, the most common being designated PAR56 and PAR64. The number indicates the diameter of the housing in eighths of an inch (so a PAR64 is eight inches (~20cm) in diameter).
Uses
PARs are frequently used in Rock and Roll shows, especially in combination with smoke/hazer machines which make the path of the beam visible. Because of the lack of control over the beam diameter, shape, and sharpness the PARs are rarely used in a front of house position, particularly in theatres, but are used often as top lights and for special effects.
The oval pool characteristic of traditional PARs are falling into disuse with modern PARs favoring a PC based lens. This can be attributed to their popularity in Rock and Roll shows where a pool of light is preferred to an oval of light, which is more useful in stage lighting to create areas. A second reason for this change is that the style of car headlamps that PARs were originally based on are no longer mass produced, so most companies making PARs have more control over the lens than previously and are deferring to their largest customer.
References
| L i g h t i n g and L a m p s | ||
|---|---|---|
| Incandescent: | Incandescent light bulb>Conventional - Halogen - Parabolic Aluminized Reflector (PAR) |
|
| Fluorescent: | Compact fluorescent lamp>Compact Fluorescent (CFL) - Linear fluorescent - Induction lamp | |
| Gas discharge: | High-intensity discharge lamp>High-Intensity Discharge (HID) - Mercury-vapor - Metal-halide - Neon - Sodium vapor | |
| Electric arc: | Arc lamp - Hydrargyrum medium-arc iodide>HMI - Xenon arc - Yablochkov candle | |
| Combustion: | Carbide lamp>Acetylene/Carbide - Candle - Gas lighting - Kerosene lamp - Limelight - Oil lamp - Safety lamp | |
| Other types: | Sulfur lamp - Light-emitting diode>Light-Emitting Diode (LED) - Optical fiber - Plasma | |
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