Stage lighting is the craft of lighting as it applies to the production of theater, dance and other performance arts. Several different types of stage lighting instruments are used in this discipline. In addition to basic lighting, modern stage lighting can include special effects, such as lasers and fog machines. People who work on stage lighting are referred to as lighting technicians or lighting designers; the equipment used for stage lighting are used in other lighting applications, including corporate events, trade shows, broadcast television, film production, photographic studios, other types of live events. The personnel needed to install and control the equipment cross over into these different areas of "stage lighting" applications; the earliest known form of stage lighting was during the early Grecian theaters. They would build their theatres facing east to west so that in the afternoon they could perform plays and have the natural sunlight hit the actors, but not those seated in the orchestra.
Natural light continued to be utilized when playhouses were built with a large circular opening at the top of the theater. Early Modern English theaters were roofless, allowing natural light to be utilized for lighting the stage; as theaters moved indoors, artificial lighting became a necessity and it was developed as theaters and technology became more advanced. At an unknown date, candlelight was introduced which brought more developments to theatrical lighting across Europe. While Oliver Cromwell was ruling Britain, all stage production was suspended in 1642 and no advancements were made to English theaters. During this theatrical famine, great developments were being made in theaters on the European mainland. Charles II, who would become King Charles II witnessed Italian theatrical methods and brought them back to England when he came to power. New playhouses were built in their large sizes called for more elaborate lighting. After the refurbishing of the theaters, it was found that the "main source of light in Restoration theaters to be chandeliers" which were "concentrated toward the front of the house, over the forestage".
English theatres during this time used dipped candles to light sconces. Dipped candles were made by dipping a wick into hot wax to create a cylindrical candle. Candles needed frequent trimming and relighting regardless of what was happening on-stage because "they dripped hot grease on both the audience and actors". Chandeliers blocked the view of some patrons. There were two different types of Restoration theaters in England: Restoration commercial theaters and Restoration court theaters. Commercial theaters tended to be more "conservative in their lighting, for economic reasons" and therefore used "candle-burning chandeliers" primarily. Court theatres could afford to "use most of the Continental innovations" in their productions. Theaters such as the Drury Lane Theatre and the Covent Garden Theatre were lit by a large central chandelier and had a varying number of smaller stage chandeliers and candle sconces around the walls of the theaters. Two main court theaters, built between 1660 and 1665, were the Hall Theatre.
Chandeliers and sconces seemed to be the primary lighting sources here but other developments were being made at the Hall. By the 1670s, the Hall Theatre started using footlights, between 1670 and 1689 they used candles or lamps, it can be noted that by the end of the 17th century, "French and English stages were similar". There is not much written on theatrical lighting in England at the end of the 17th century and from the little information historians do have, not much changed by the middle of the 18th century. Gas lighting hit the English stage in the early 1800s beginning with the Drury Lane and Covent Garden theaters. In the 1820s, a new type of artificial illumination was developed. In this type of illumination, a gas flame is used to heat a cylinder of quicklime. Upon reaching a certain temperature, the quicklime would begin to incandesce; this illumination could be directed by reflectors and lenses. It took some time from the development of this new Limelight before it found its way into theatrical use, which started around 1837.
Limelight became popular in the 1860s and beyond. Lighting advances made in English theaters during this time frame paved the way for the many lighting advances in the modern theatrical world. Stage lighting has multiple functions, including: Selective visibility: The ability to see what is occurring on stage. Any lighting design will be ineffective if the viewers cannot see the characters, unless this is the explicit intent. Revelation of form: Altering the perception of shapes onstage three-dimensional stage elements. Focus: Directing the audience's attention to an area of the stage or distracting them from another. Mood: Setting the tone of a scene. Harsh red light has a different effect than soft lavender light. Location and time of day: Establishing or altering position in time and space. Blues can suggest night time while red can suggest a sunrise or sunset. Use of mechanical filters to project sky scenes, the Moon, etc. Projection/stage elements: Lighting may be used to project scenery or to act as scenery onstage.
Plot: A lighting event may trigger or advance the action onstage and off. Composition: Lighting may be used to show only the areas of the stage which the designer wants the audience to see, to "paint a picture". Effect: In pop and rock concerts or DJ shows or raves, colored lights and lasers may be used as a visual effect. Ligh
Dimmers are devices connected to a light fixture and used to lower the brightness of light. By changing the voltage waveform applied to the lamp, it is possible to lower the intensity of the light output. Although variable-voltage devices are used for various purposes, the term dimmer is reserved for those intended to control light output from resistive incandescent and compact fluorescent lights and light-emitting diodes. More specialized equipment is needed to dim fluorescent, mercury vapor, solid-state, other arc lighting. Dimmers range in size from small units the size of domestic light switches to high-power units used in large theatrical or architectural lighting installations. Small domestic dimmers are directly controlled, although remote control systems are available. Modern professional dimmers are controlled by a digital control system like DMX or DALI. In newer systems, these protocols are used in conjunction with ethernet. In the professional lighting industry, changes in intensity are called "fades" and can be "fade up" or "fade down".
Dimmers with direct manual control had a limit on the speed they could be varied at but this problem has been eliminated with modern digital units. Modern dimmers are built from semiconductors instead of variable resistors, because they have higher efficiency. A variable resistor would dissipate power as heat and acts as a voltage divider. Since semiconductor or solid-state dimmers switch between a low resistance "on" state and a high resistance "off" state, they dissipate little power compared with the controlled load. Early dimmers were directly controlled through the manual manipulation of large dimmer panels; this required all power to come through the lighting control location, which could be inconvenient and dangerous for large or high-powered systems, such as those used for stage lighting. In 1896, Granville Woods patented his "Safety Dimmer", which reduced wasted energy by reducing the amount of energy generated to match desired demand rather than burning off unwanted energy. In 1959, Joel S. Spira, who would found the Lutron Electronics Company in 1961, invented a dimmer based on a diode and a tapped autotransformer, saving energy and allowing the dimmer to be installed in a standard electrical wallbox.
In 1966, Eugene Alessio patented a light bulb socket adapter for adjusting a light level on a single light bulb using a triac. To house this device, he decided on a 2-inch round device with one end capable of being screwed into a light bulb socket and the other end able to receive a light bulb; when solid-state dimmers came into use, analog remote control systems became feasible. The wire for the control systems was much smaller than the heavy power cables of previous lighting systems; each dimmer had its own control wires, resulting in many wires leaving the lighting control location. More recent digital control protocols such as DMX512, DALI, or one of the many Ethernet-based protocols like Art-Net, ETCnet, sACN, ShowNet or KiNET enable the control of a large number of dimmers through a single cable. Dimmers based on rheostats were inefficient since they would dissipate a significant portion of the power rating of the load as heat, they were large and required plenty of cooling air. Because their dimming effect depended a great deal on the total load applied to each rheostat, the load needed to be matched carefully to the power rating of the rheostat.
As they relied on mechanical control they were slow and it was difficult to change many channels at a time. Early examples of a rheostat dimmer include liquid rheostat; the closer the contacts to each other, the more voltage was available for the light. Salt water dimmers required regular addition of maintenance due to corrosion; the coil-rotation transformer used a fixed-position electromagnet coil in conjunction with a variable-position coil to vary the voltage in the line by varying the alignment of the two coils. Rotated 90 degrees apart, the secondary coil is affected by two equal but opposite fields from the primary, which cancel each other out and produce no voltage in the secondary; these coils resembled the standard rotor and stator as used in an electric motor, except that the rotor was held against rotation using brakes and was moved to specific positions using high-torque gearing. Because the rotor did not turn a complete revolution, a commutator was not required and long flexible cables could be used on the rotor instead.
Variable autotransformers were introduced. While they are still nearly as large as rheostat dimmers, which they resemble, they are efficient devices, their voltage output, so their dimming effect, is independent of the load applied so it was far easier to design the lighting that would be attached to each autotransformer channel. Remote control of the dimmers was still unpractical, although some dimmers were equipped with motor drives that could and reduce or increase the brightness of the attached lamps. Autotransformers are used for other applications. Solid-state or semiconductor dimmers were introduced to solve some of these problems. Semiconductor dimmers switch on at an adjustable time after the start of each alternating current half-cycle, thereby
DMX512 is a standard for digital communication networks that are used to control stage lighting and effects. It was intended as a standardized method for controlling light dimmers, prior to DMX512, had employed various incompatible proprietary protocols, it soon became the primary method for linking controllers to dimmers and special effects devices such as fog machines and intelligent lights. DMX has expanded to uses in non-theatrical interior and architectural lighting, at scales ranging from strings of Christmas lights to electronic billboards. DMX can now be used to control anything, reflecting its popularity in theaters and venues. DMX512 employs EIA-485 differential signaling at its physical layer, in conjunction with a variable-size, packet-based communication protocol, it is unidirectional. DMX512 does not include automatic error checking and correction, so is not an appropriate control for hazardous applications, such as pyrotechnics or movement of theatrical rigging. False triggering may be caused by electromagnetic interference, static electricity discharges, improper cable termination, excessively long cables, or poor quality cables.
Developed by the Engineering Commission of United States Institute for Theatre Technology, the DMX512 standard was created in 1986, with subsequent revisions in 1990 leading to USITT DMX512/1990. In 1998 the Entertainment Services and Technology Association began a revision process to develop the standard as an ANSI standard; the resulting revised standard, known as "Entertainment Technology—USITT DMX512-A—Asynchronous Serial Digital Data Transmission Standard for Controlling Lighting Equipment and Accessories", was approved by the American National Standards Institute in November 2004. It was revised again in 2008, is the current standard known as "E1.11 – 2008, USITT DMX512-A", or just "DMX512-A". A DMX512 network employs a multi-drop bus topology with nodes strung together in what is called a daisy chain. A network consists of a single DMX512 controller –, the master of the network — and one or more slave devices. For example, a lighting console is employed as the controller for a network of slave devices such as dimmers, fog machines and intelligent lights.
Each slave device has a DMX512 "IN" connector and an "OUT" connector as well. The controller, which has only an OUT connector, is connected via a DMX512 cable to the IN connector of the first slave. A second cable links the OUT or THRU connector of the first slave to the IN connector of the next slave in the chain, so on. For example, the block diagram below shows a simple network consisting of a controller and three slaves; the specification requires a'terminator' to be connected to the final OUT or THRU connector of the last slave on the daisy chain, which would otherwise be unconnected. A terminator is a stand-alone male connector with an integral 120 Ω resistor connected across the primary data signal pair. If a secondary data pair is used, a termination resistor is connected across it as well. Although simple systems will sometimes function without a terminator, the standard requires its use; some DMX slave devices have built-in terminators that can be manually activated with a mechanical switch or by software, or by automatically sensing the absence of a connected cable.
A DMX512 network is called a "DMX universe". Each OUT connector on a DMX512 controller can control a single universe. Smaller controllers may have a single OUT connector, enabling them to control only one universe, whereas large control desks may have the capacity to control multiple universes, with an OUT connector provided for each universe. DMX512 data is transmitted over a differential pair using EIA-485 voltage levels. DMX512 electrical specifications are identical to those of the EIA-485-A standard, except where stated otherwise in E1.11. DMX512 is a bus network no more than 400 metres long, with not more than 32 unit loads on a single bus. If more than 32 unit loads need to communicate, the network can be expanded across parallel buses using DMX splitters. Network wiring consists of a shielded twisted pair, with a characteristic impedance of 120 Ohms, with a termination resistor at the end of the cable furthest from the controller to absorb signal reflections. DMX512 has two twisted pair data paths, although specification only defines the use of one of the twisted pairs.
The second pair is undefined, but required by the electrical specification. For short cable runs of less than about 45 metres with only a few devices, it is sometimes possible to operate without termination. At short distances, cables with higher capacitance and different characteristic impedance such as microphone cable can be used; as the cable length or number of devices increases, following the specification for termination and correct cable impedance becomes more important. The E1.11 electrical specification addresses the connection of DMX512 signal common to Earth ground. The standard recommends that transmitter ports have a low impedance connection between signal common and ground, it is further recommended that receivers have a high impedance connection between signal common and ground. The standard allows for isolated transmitter ports; the standard allows for non-isolated receivers. The standard recommends that systems ground the signal common at only one p
Lighting control console
A lighting control console is an electronic device used in theatrical lighting design to control multiple lights at once. They are used throughout the entertainment industry and are placed at the Front of House position or in a control booth. All lighting control consoles can control dimmers. Many modern consoles can control Intelligent lighting, fog machines and hazers, other special effects devices; some consoles can interface with other electronic performance hardware to improve synchronization or unify their control. Lighting consoles communicate with the dimmers and other devices in the lighting system via an electronic control protocol; the most common protocol used in the entertainment industry today is DMX512, although other protocols may still be found in use, newer protocols such as ACN and DMX-512-A are evolving to meet the demands of increasing device sophistication. Consoles vary from small preset boards to dedicated moving light consoles; the purpose of all lighting consoles, however is the same: to consolidate control of the lights into an organized, easy-to-use system, so that the lighting designer can concentrate on producing a good show.
Most consoles accept MIDI Show Control signals and commands to allow show control systems to integrate their capabilities into more complex shows. Preset boards are the most basic lighting consoles—and the most prevalent in smaller installations, they consist of two or more identical fader banks, called scenes. The faders on these scenes can be manually adjusted; each scene has the same number of channels. So the console operator can build a scene offline or in "blind", a cross-fader or submaster is used to selectively mix or fade between the different scenes. At least with a preset board, the operator has a cue sheet for each scene, a diagram of the board with the faders in their positions, as determined by the lighting designer; the operator sets the faders into their positions based on the cue sheets. During a cue, the operator sets the next scene; the operator makes the transition between the scenes using the cross-fader. Preset boards are not as prevalent since the advent of digital memory consoles, which can store scenes digitally, are much less cumbersome but more expensive than preset boards.
However, for small setups such as that of a DJ, they remain the board of choice for their simple to use interface and relative flexibility. Preset boards control only conventional lights. However, this is not recommended. Memory-based consoles have become popular in all larger installations theatres; this type of controller has completely replaced preset consoles as controllers of choice. Memory consoles are preferable in productions where scenes do not change from show to show, such as a theatre production, because scenes are designed and digitally recorded, so there is less room for human error, less time between lighting cues is required to produce the same result, they allow for lighting cues to contain larger channel counts due to the same time savings gained from not physically moving individual channel faders. Many memory consoles have a bank of faders; these faders can be programmed to control a group of channels. The console may have provision to operate in analog to a manual desk for programming scenes or live control.
On more advanced consoles, faders can be used to control effects and moving light effects. Moving Light Controllers are another step up in sophistication from Memory Consoles; as well as being capable of controlling ordinary luminares via dimmers, they provide additional controls for intelligent fixtures. On midrange controllers, these are provided as a section separate from main Preset and Cue stack controls; these include an array of buttons allowing the operator to select the fixture or fixtures they want to control, a joystick, or a number of wheels or rotary encoders to control fixture attributes such as the orientation, colour, gobos etc. found in this type of light. Unlike a fader that shows its value based on the position of a slider, a wheel is continuously variable and provides no visual feedback for the value of a particular control; some form of display such as LCD or LED is therefore vital for displaying this information. The more advanced desks have one or more touchscreens, present a GUI that integrates all the aspects of the lighting.
As there is no standard way of controlling an intelligent light, an important function for this type of desk is to consolidate the various ways in which the hundreds of types of intelligent lights are controlled into a single abstract interface for the user. By integrating knowledge of different fixtures and their attributes into the lighting desk software, the detail of how an attribute such as pan or tilt is controlled for one device vs. another can be hidden from the operator. This frees the operator to think in terms of what they want to achieve instead of how it is achieved for any