If you are just starting out in the world of lighting, it is common to come across concepts and terms that can be confusing. These terms can also vary in meaning depending on the context in which they are applied and are often anglicisms that we may never have heard before. To help you get your bearings, We have developed a list of key concepts in the field of lightingKnowing and understanding these terms will help you navigate with greater confidence and reduce the feeling of being lost when entering this fascinating world.
Glossary of stage lighting
Array: Term used to describe a set of LED emitters in a luminaire. The LED color recipe of an array defines the type of light that fixture can produce (the color gamut).
Increased: Slow increase in light intensity.
Backstage: Stage area located behind the proscenium and the scenery.
open white: Term used to describe a gel-free light. When talking about LEDs, it means that all the emitters are at their maximum, creating white light.
Blind: Dark stage state.
Articulated arm: A metal bracket that attaches a spotlight to an arm.
Cable/Sling: Steel cable used to prevent a stage light from falling if the main suspension point fails. Replaced by safety bonds.
Boxes/Alas: The side areas of a stage that the audience does not see.
Control channel: The control channel is the numerical name the designer uses for a luminaire or set of luminaires that are controlled together. Control channels are used to group sets of fixtures or fixtures in a logical manner related to the way the designer thinks about the design, rather than the physical location of it on site.
Tracking gun: Long-range profile spotlight mounted on a rotating base, used to follow a person as they move.
Cyclorama: Row of spotlights used to illuminate a backdrop from below.
Cyclorama (cyc): White backdrop or painted surface at the back of the stage.
Against light: Light that illuminates a subject from behind and is used to highlight it from the background and define its shape.
Lighting control: Another term for a lighting control console or table.
inrush current: Overcurrent in an electrical circuit that occurs when an appliance is turned on for the first time. The inrush current of a set of devices can exceed the rated current of a circuit and cause a circuit breaker to trip, even though the normal operating current is below the limit of that circuit.
blades: Metal plates that fit into the luminaire, used to control the shape and size of the projected beam.
Cue: Starting point of a lighting change. Word, action or signal of the performer or stage director that initiates a lighting change or any other change on the stage.
Iris: Device with an adjustable hole that can modify the diameter of the projected beam.
Differential: A safety device connected to a power supply to detect whether the current between the excited and return conductors of a circuit is balanced. A current difference in these two lines may indicate a short circuit or a leak to the ground conductor (a live discharge in progress). The imbalance causes the RCD to trip, breaking the circuit.
dimmer: A device that increases or reduces the power reaching the luminaires of a tungsten lighting system, normally in response to signals from a lighting control panel.
dimmer rack: A wall- or floor-mounted cabinet containing multiple dimmer switches, controlled by a lighting control desk. Dimmers in a rack can sometimes be replaced by relays, which turn power on or off to a circuit, such as a switch. The ETC ColorSource ThruPower rack combines dimmers and relays in each lighting circuit – the user can change the settings for each circuit in the rack. The circuit can then be used with a traditional tungsten load (with a dimmer) or with LEDs, moving lights, or other devices requiring constant power (with a relay).
dips: Low-level power outlets or plugs below the stage surface.
Assistant Stage Director: This is the person in charge of directing the show on a daily basis. Their job is to give all the lighting instructions, scene changes, etc., ensuring that the performance goes as rehearsed and agreed.
Beam dispersion: The light from theatrical luminaires usually forms a conical beam, narrow at the luminaire and wider as the light moves away from the luminaire. The angle of the cone is called the beam spread. This value is important to calculate the amount of light that will reach the stage from a luminaire installed at a certain distance from the stage.
Circuit breaker: A device that automatically interrupts an electrical circuit when an overload fault is detected. This is usually due to a short circuit or too much load being connected.
DMX512-A: Multiplex Digital protocol used to control dimmers and devices from a lighting control table.
DMX Terminator: Device used to buffer the end of a DMX512-A signal section. It consists of an XLR-M connector with a 120 ohm resistor soldered between pins 1 and 2. They can be made by hand or purchased from an equipment dealer.
Push scenario: stage that extends into the interior of the auditorium and is surrounded on three sides by seats for the public.
Spike: Short metal rod that connects a luminaire to a lighting stand.
Farol: Original term to designate a stage luminaire.
Fade Out: When the light intensity value goes down.
Focus: Generic name for any luminaire that has a controllable beam of light.
Fresnel: Stage luminaire equipped with a Fresnel lens that produces a soft-edged and controllable beam of light.
Front of House (FoH): The area located in front of the stage or proscenium that contains the audience.
Light leakage: Unwanted light from a luminaire.
Fuse: Safety device installed on older dimmer circuits and some sockets (13A) to detect overloads. Modern regulators use circuit breakers.
Cast: Gradual change from one lighting state to another in which the incoming state replaces the previous one.
gamut: Complete range of colors that an LED luminaire can produce. The smaller the number of colors in the LED matrix, the smaller the color gamut.
Claw: Hook-shaped clamp used to fix luminaires to a bar.
Gelatin: Sheets of colored transparent material placed on the front of stage fixtures to color the light beam (made from gelatin, the original material for color filters).
Mushroom: Metal or glass disc with motifs that, when fitted into the luminaires, projects the motif onto the stage, stage or scenery.
Spot lighting: A light intended to perform a very specific task, such as illuminating an actor during a big monologue on stage or illuminating a presenter at a podium. Specialty lights can be added to make existing equipment better fit the needs of a show.
Lamp: Glass envelope containing a tungsten filament or other illumination source. It is not required in LED luminaires.
PAR lamp: Sealed beam lamp to fit into a PARcan.
LED – Light Emitting Diode: An LED is a small electronic device that emits light of a specific color. LEDs can produce very narrow frequencies of light or can produce a wider range of frequencies when made with phosphors. LEDs are combined in arrays to produce light in leisure luminaires: the more colors available in an array, the greater the range of colored light a luminaire can produce.
Fixed lens: Lens installed in a profile luminaire that will produce a beam of light with a known or "fixed" angle.
Lira: The U-shaped metal support ring attached to a luminaire.
Work lights (1): Independent lighting system, not connected to the stage dimming systems, which can be turned on and off according to the needs of the stage crew.
Work lights (2): Sometimes it is necessary to light the stage so that the crew can prepare a new scene. In some circumstances, normal work lights would be too bright, so a signal is incorporated into the lighting pattern to allow the team to work quickly and safely.
Luminaire Cutout: Stage luminaire equipped with one (fixed angle) or two (zoom) lenses. The profile can project images or motifs (gobos) and can be precisely focused and shaped by internal shutters.
Front light: Light that falls on a subject from the same direction in which the audience is looking. The front light is used for the visibility of the actors' faces.
Side light: Light falling on the object from the left or right (from the audience's point of view). Side light is used to reveal the shape of three-dimensional objects or artists.
Lighting control table: System used to control dimmers and connected devices and to store programmed information for a production. Also known as a lighting board or console.
Color swatch: A small booklet of color filter material samples including their name, number and spectral distribution characteristics. These brochures serve as a reference for the lighting designer when choosing colors for a production. Color filters are typically designed to work in conventional tungsten luminaires, but some manufacturers also make color filters for white light LED luminaires. Color filter brochures are available from theatrical equipment dealers.
Offstage: Any area of a stage that cannot be seen by the audience.
Ohm: Unit of electrical resistance. Conductors (cables) are rated in ohms.
Onstage: Any area of a stage that can be seen by the audience.
OP (Opposite Prompt): A stage direction meaning stage right.
Bread: To move a spotlight or mobile light in a generally horizontal movement.
BY: Luminaire based on a sealed beam lamp contained in a simple can-shaped housing.
Patch Panel: A physical connection point between the numbered circuits in the theater and the dimmers in the dimmer rack. Patch panels have been replaced by per-circuit dimmer systems in which each circuit is directly wired to a dimmer position in a dimmer rack.
Patching: Linking dimmer circuits or DMX addresses to control channels on the lighting control desk.
Map: The drawing that indicates where all the luminaires should be placed and how they should be connected to the lighting system. This plan is usually drawn to scale.
Light plan: Schematic drawing of the lighting installation, used to communicate to technicians where to hang luminaires and how the luminaires will be patched to the lighting control desk.
Gobo holder: Part of a profile projector, located at the internal focal point where gobos and other beamforming devices can be placed.
Practical: A prop or other electrical device (table lamp, television, etc.) that is, or appears to be, operated by a cast member. Depending on the performance, the spotter may not be connected to the dimmer system.
Preset (1): Term originally applied to a simple manual lighting table in which two sets of faders (A and B) were raised to the levels needed in two different scenes. A cross-fader provided a means to fade between “Preset A” and “Preset B.” Now it is not used much.
Preset(2): Term used on some modern control desks to denote a single fader to which a number of channels have been assigned and recorded at different intensities. They can also be called submasters.
Preset (3): State of the lighting on the stage before the performance begins.
Projector: Stage luminaires that produce a wide beam of light. Projectors do not usually have lenses.
Proscenium: The proscenium is a part of the theatrical stage that faces the curtain and extends from the edge of the stage to the front line of the scene. It is where the actors usually stand for much of the play.
Prompt: Lines given to an actor who has forgotten his place. The "prompter" is the person who would normally give these lines, but this is no longer used in professional theatre. If lines are missed, the “book” assistant stage manager (DSM) will say the missing dialogue.
Proscenium (arch): Arch or opening in the front wall of the stage, which frames the audience's view of the show. Some stage spaces do not have a proscenium; Others install a temporary "false proscenium" made of curtains, curtains or decorations.
PS (Prompt Side): A stage direction meaning stage left.
All time lap record or recording: The process of saving information to a computerized console or memory. All information relating to the show is recorded and will include cues, timings, soft patching and other setup procedures. The combined show data is saved in a show file, which can be stored on the console's own hard drive and on a USB flash drive for back-up.
Rig: The lighting installation and placement of luminaires for a specific show. The setup may vary from show to show.
Curtain: Set of curtains that can be closed along the front of the stage (behind the proscenium, if there is one).
Threw: Distance from a luminaire to the stage or an area of the stage. The scope affects the size of the light beam and will help determine what size lens to use.
Tungsten-halogen: The correct description of a tungsten lamp. A thin tungsten filament rests on a quartz crystal envelope filled with halogen gas.
Upstage: The area of the stage closest to the back wall or the cyclorama.
UV: Ultraviolet light, used for special effects.
Items: Smooth bar or lighting bar with internal wiring (IWB) suspended above the stage or auditorium on which the spotlights are fixed.
Volt: Power unit that quantifies the potential difference carried by one ampere of current against one ohm of resistance. Electrical supplies are rated in volts.
Watt: Power unit that quantifies the rate of energy transfer. It is used to describe the energy consumption of lamps and appliances. The watt is equal to the voltage of a circuit multiplied by its amperage (W=VA).
Zoom: System composed of two lenses that can be adjusted to vary the size and focus of a beam of light coming from a profile luminaire.