Сахналық жарықтандыру құралдары

Device that emits light to illuminate performers

Stage lighting instruments (lanterns, or luminaires in Europe) are used in stage lighting to illuminate theatrical productions, concerts, and other performances taking place in live performance venues. They are also used to light television studios and sound stages. Many stagecraft terms vary between the United States and the United Kingdom. In the United States, lighting fixtures are often called "instruments" or "units". In the UK, they are called "lanterns" or "luminaires". This article mainly uses terms common to the United States.

The lamp housing is a metal or plastic container that serves as a body for the entire instrument and prevents light from spilling in unwanted directions. It comprises all of the exterior of the fixture except for the lens or opening. The housing may be designed with specific elements that help reduce heat and increase the efficiency of a lamp. Older instruments were made from rolled and machined steel or aluminum. With the advent of the Source Four, many lighting instruments are being made from die cast metal. Die casting allows for one single, light weight body that is more economical to produce and use. The first lantern to make use of die castings was the Strand Pattern 23 designed by Fred Bentham in 1953, this small mirror spot enjoyed a 30 year production run and found its way into many British schools, halls and theaters. Some instruments are made from plastic, such as the Selecon Pacific.

The opening is the gap in the housing from where the beam of light is intended to come. Many fixtures use a lens to help control the beam of light, though some, such as border or cyclorama lights, do not have any lenses or optics other than the reflector. The lens and the reflector, along with other beam altering devices, are both considered part of the optics system. There are two main lens types. Profile Lens Systems and Wash Lens Systems. Instruments with profile lens systems usually have a beam that is narrow and hard edged. ERS lights and follow spots use these lenses. On the other hand, fixtures such as PAR's and Fresnels use wash lens systems. The wash lens system casts a diffused wash of light with a softer beam edge. In addition, safety cables (a loop of aircraft cable terminated with carabiners) are used to support the lighting instrument in case the clamp fails. A side arm is a metal pole bolted to the instrument with a clamp on the end. This enables the instrument to be hung to the side of an electric as opposed to below it.

All instruments need some type of source to produce light. The bulbs used are referred to as lamps. Stage lighting instruments typically use incandescent lamps, tungsten halogen lamps, encapsulated arcs, or LEDs. LEDs have now been added to fixtures such as the Source Four LED, which looks similar to the source four onstage, but is controlled with LEDs. Incandescent lamps are most likely the type of light one is used to seeing. They are typical household lights that are usually between 40 and 100 watts. However, the US has been taking them out of production due to their inefficient nature. Typically, an incandescent lamp has a tungsten filament surrounded by an inert gas. This is all encapsulated by a bulb. The inert gas stops the formation of anything that could darken the bulb, such as carbon. The bulb is usually made from Pyrex or synthetic quartz. Incandescent lamps also have a base. The base screws into a socket and serves as an electrical contact point for the socket and the filament inside. For the most part, higher watt bulbs will use larger bases. Incandescent bulbs for stage lighting may have pins on the bottom instead of a screw. This allows them to be positioned properly in relation to a reflector. The filament of the lamp is usually tightly coiled tungsten wire.

Strip lights, also known as cyclorama or cyc lights (thus named because they are effective for lighting the cyclorama, a curtain at the back of the stage), border lights, and codas (by the brand name), are long housings typically containing multiple lamps arranged along the length of the instrument and emitting light perpendicular to its length. Lamps are often covered with gels of multiple colors (often red, green, and blue, which, in theory, allow almost any color to be mixed) with each color controlled by a separate electrical dimmer circuit. Many striplights use round pieces of glass (called roundels) rather than plastic gels for color. Roundels can sustain heavy use for a long time without fading and are often found in more permanent installations.

Scoop lights or scoops are circular fixtures that do not have any lenses. They have an ellipsoidal 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 light cannot be focused at all (even PARs allow more control than scoops). Scoops are most often used to flood the stage with light from above, or to light backdrops. Scoops can have gels affixed. Occasionally they are used as work lights (see below).

House lights provide light on the theater's seats and aisles for the audience before and after performances and during intermissions. They are generally incandescent lights, however fluorescent lights or scoops may be used in some instances. House lights are often controlled by dimmers, but are sometimes on simple switches. Worklights provide general lighting backstage or in the house, and are often fluorescent fixtures. Work lights are almost always non dimmed. House and work lights are usually off during performances but are occasionally included in the lighting design to establish focus or emphasize plot elements. When the house lights are not on a dimmer, the switch is usually under the control of the stage manager.

LED stage lighting instruments are stage lighting instruments that use light emitting diodes (LEDs) as a light source. LED instruments are an alternative to traditional stage lighting instruments which use halogen lamp or high intensity discharge lamps. Like other LED instruments, they have high light output with lower power consumption. Most LED fixtures use three or more colors (usually red, green, and blue) which can be mixed to hypothetically create any color.

LED stage lights come in four main types. PAR cans, spotlights, striplights, and "moving head" types. In LED PAR cans, a round printed circuit board with LEDs mounted on is used in place of a PAR lamp. Moving head types can either be a bank of LEDs mounted on a yoke or more conventional moving head lights with the bulb replaced with an LED bank.

LED instruments can and have been used to replace any conventional lighting fixture, and some shows, such as Radiohead's 2008 tour, have used only LED lighting instruments. Most shows use LEDs only for lighting cycloramas, or as top, side, or back light due to their low throw distance. They can also be used as audience blinders (lights pointed directly at the audience from a low angle).

A spotlight is any lighting instrument used in theater to create a pool of light on the stage. There are many different types of spotlights which break down into three general areas:
Fresnel lanterns or Fresnels (US) are small fixtures giving a soft edged spot or pool of light. Their name comes from the distinctive ridged Fresnel lens used on the front. Profile spots (UK) or ellipsoidal reflector spotlights (US) 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 follow performers on the stage. The term Profile Spot used in the UK refers to a focussing spotlight which may, or may not use the ellipsoidal reflector design, this design was not common in the UK until the 1970s and many UK and European manufacturers have still to adopt this design instead preferring a twin PC lens design. Pebble Convex lanterns (or "PCs") are similar to Fresnels, but use a plano convex lens with a pebbled effect on the planar (flat) side, resulting in less "spill" outside the main beam. They are used much more widely in Europe than North America.

A Fresnel lantern (UK), or simply Fresnel (US), employs a Fresnel lens to wash light over an area of the stage. The lens is named after French physicist Augustin Jean Fresnel, and consequently pronounced with a silent "s". 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, top light, and side light. Another method of controlling the spread of light is to use either a top hat (also referred to as a snoot), which generally limits the light coming out, or a barn door, whose flaps work as though they were shutters on an ERS (shown on the right). These methods limit light output and keep excess light from spilling into the eyes of audience members or where it is not desired. Fresnels use a spherical reflector, with the lamp at the focus point. The lamp and reflector remain a fixed unit inside the housing, and are moved forward and back to focus the light. This is accomplished using a slider on the bottom or side of the lantern, or using 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. In 1999, ETC introduced a new lighting fixture, the Source Four PARNel, which combined the design of the PAR fixture with that of the Fresnel. The fixture is more versatile, allowing for a flood or a softer spot. The major components of an ERS light are the casing in which the internal parts are mounted, an ellipsoidal reflector located in the back of the casing(truncated conical ellipse), a lamp mounted to position the filament at the rear focal point of the ellipsoid, a dual plano convex lens (two plano convex lenses facing each other in the barrel), and at the front, a gel frame to hold the color gel. The light from the lamp is efficiently gathered by the ellipsoidal reflector and sent forward through the gate, shutters and lens system. ERS instruments allow many different lens tubes to be used with the same body. This makes them more versatile, since a venue can purchase varying degrees of barrels without buying as many instruments. Many manufacturers also produce zoom lenses which offer the ability to change the beam angle. Some zoom ranges have a poorer optical quality making them difficult to use in sharp focus.

The field angle of an instrument is the angle of the beam of light where it reaches 10% of the intensity of the center of the beam. Most manufacturers now use field angle to indicate the spread that the fixture has. However, older fixtures are described by the width of the lens x focal length of the instrument. For example, a 6x9 ellipsoidal would have a 6" lens and a focal length of 9" (creating an approximately 37° beam angle). This nomenclature was used because traditionally a larger lens directly equated with more light output. This is no longer necessarily true, so most manufacturers now identify their fixtures by beam angle and light output. As the field angle narrows, the instrument can either be used further from the stage to create a similarly sized beam as a closer, larger instrument, or it can be used from the same distance to create a smaller beam.

A beam projector is a lensless instrument with very little beam spread. It uses two reflectors. The primary reflector is a parabolic reflector and the secondary reflector is a spherical reflector. The parabolic reflector directs the light into nearly parallel beams, and the spherical reflector is placed in front of the lamp to reflect light from the lamp back to the parabolic reflector, which reduces spill. The result is an intense shaft of light that cannot be easily controlled or modified. The beam projector no longer is used to the extent that it once was, as newer fixtures and PAR lamps have created easier ways to produce the effect.

The followspot (also called a spotlight, trackspot, lime (uk), or dome) is a lighting instrument that is moved during a performance by an operator or by DMX control to provide emphasis or extra illumination and usually to follow a specific performer moving around the stage. Follow spots are commonly used in musical theater and opera to highlight the stars of a performance, but may be used in dramas as well. 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 its own safety concerns. Followspots contain a variety of operator controlled optical mechanisms. They may include mechanical shutters, which allow the light to be doused without turning off the lamp, lenses to control and focus beam width, and internal color gels, often in a color magazine.

Moving lights (or intelligent fixtures) began to gain widespread acceptance in the concert industry in the early 1980s. As the digital age progressed, the cost of these fixtures reduced, and they are increasingly used in many 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 motorized yoke. Usually they also contain other controls to shape, texture and color the light, such as gobo or dichroic wheels. Almost all of the parameters are controlled by step motors. These are capable of very precise movement in either direction that can count a specific number of steps. This allows the fixture to quickly and accurately move.