LIGHTING TERMS A-DRESS REHEARSAL

THEATER & FILM 

LIGHTING VOCABULARY/TERMS 

15A PLUG 

Standard domestic power connector in the US. 

20A PLUG 

Standard power connector in US theaters. Three round metal contacts (live, neutral and earth); 

ADAPTOR 

1) Connector which allows two or more electrical devices to be connected to a single power outlet. The connection is normally parallel, that is, each device is fed the same voltage, but the current is divided between them. Sometimes known as a 'Twofer'. A three-way splitter is known as a 'Threefer'. A Series splitter is also available where a voltage is shared equally between two loads. 2) Also an ADAPTOR can be the same as a JUMPER. See SERIES SPLITTER, JUMPER and GRELCO. 

AMBIENT LIGHT 

The light in a venue with no stage-lighting sources switched on. Background light. 

AMPERE (AMP) 

The standard unit for measurement of electrical current passing through a circuit (usually abbreviated to AMP). Written as 'I' in equations. Cables, fuses and switches are designated by their current carrying capacity. (Following phrase refers to UK standards). Square pin plugs are rated at 15 Amps maximum and Side pin plugs at 20 Amps maximum, depending on the size of the pins. 

ATTRIBUTES 

The controllable parameters of a moving light are known as the ATTRIBUTES. All moving lights will have pan & tilt, with many having color wheels, gobo selection, gobo rotation etc. as additional attributes.

BACK PROJECTION 

See PROJECTION. 

BACKLIGHT 

Light coming from upstage, behind scenery or actors, to sculpt and separate them from the background 

BATTEN PIPE 

The horizontal metal (steel or alloy) tube (usually 48mm in external diameter, but can be up to 60mm) hangs from flying lines (or forming part of a grid) from which lighting equipment and scenery etc. may be suspended. Also known as a BARREL. When vertical, known as a BOOM. Sometimes known as a PIPE in the US, although many curse that usage, and demand the use of Batten ; 'A pipe is what you smoke; a batten is what you hang your instruments from.'. 

BARN DOORS 

A rotatable attachment consisting of two or four metal flaps (hinged) which is fixed to the front of a Fresnel or PC type lantern to cut off the beam in a particular direction(s). Profile lanterns use SHUTTERS to achieve a greater degree of control and accuracy. Barn Doors are also available for par cans and birdies. 

BATTENS 

1) Timber at the top and bottom of a cloth. A Sandwich batten is used to carry a hanging cloth. It comprises two flat pieces of timber screwed together with the edge of the cloth between them. 2) Timber used for joining flats together for flying. 3) Compartmentalized floodlights set up to allow color mixing. See also GROUNDROW. Low voltage battens are commonly used as light curtains & for color washes. Known in the US as a STRIPLIGHT or BORDER LIGHT. 4) US term interchangeable with PIPE for a flying bar. 

BEAM ANGLE 

The angle of the cone of light produced by a lantern. Defined as the angle within which the lowest intensity in a beam of light from a lantern is not less than one-tenth of the maximum.

BELTPACK 

Part of the communication ('cans') system in a theater, the Beltpack contains the controls and circuitry to drive the HEADSET worn by crew members. Each beltpack connects into the headset ring and back to a PSU (Power Supply Unit) which is powered from the mains. See also CANS. 

BLACKOUT 

1) Complete absence of stage lighting. Blue working lights backstage should remain on and are not usually under the control of the board, except during a Dead Blackout (DBO), when there is no onstage light. Exit signs and other emergency lighting must remain on at all times. 2) The act of turning off (or fading out) stage lighting (e.g. "This is where we go to blackout") 

BLINDERS (Audience) 

1) Lamps arranged around the stage directed into the auditorium, originally to prevent spectators seeing the stage during scene changes when the house tabs were not lowered. Now used for effect in rock concerts etc. 2) A strip of dense black material fastened behind a crack between two flats or scenic pieces to prevent light leak. Cloth hung behind a gauze to prevent transparency before the effect is required. The main control for the stage lighting. Originally known as the switchboard or dimmer board, it is now usually remote from the dimmers. The lighting operator for a show is said to be "on the board", and is sometimes known as the "board op". In the US, the board operator is said to be "running the lights". Known in the US as the Light Board. Also known as the Lighting Desk, LX desk, control desk, lighting console. 

BOOM 

1) Vertical scaffolding pole (usually 48mm diameter) on which horizontal boom arms can be mounted, carrying lanterns. Often used behind wings for side-lighting etc. Booms have a base plate (known as a TANK TRAP) or stand at the bottom and are tied off to the grid or fly floor at the top (not always necessary for short booms). Booms can also be fixed to the rear of the proscenium arch (Pros. Boom) or hanging from the ends of lighting bars. Sometimes known in the US as a light tree. A light tree mounted upstage of a Tormentor is known as a Torm Tree. 2) An arm mounted on a microphone stand.

BOOM BASE 

A wooden board with a vertical scaffold tube adapter used as a base for lighting booms. Although the base provides a degree of support (especially with added brace weights) booms often require additional support from above. 

BOOTH 

(US) Control Room. 

BORDER 

A narrow horizontal masking piece (flattage or cloth), normally of neutral color (black) to mask the lighting rig and flown scenery from the audience, and to provide an upper limit to the scene. Often used in conjunction with LEGS. Spanish: Bambalina 

BREAKOUT 

A connection at the end of a multicore cable which allows the connection of many items to it. (e.g. there is a breakout box at the end of a sound multicore cable which allows you to plug microphone cables into it). 

BREAKUP 

A commonly used abstract GOBO which gives a textured effect to the light, without throwing a specific pattern onto the stage. Used to add interest to light beams. A leafy breakup is used for outdoor scenes / forests / spooky wood etc. to break up the light on the actors faces. 

BRIDGE (CATWALK) 

1) A walkway, giving access to technical and service areas above the stage or auditorium, or linking fly-floors. See also CATWALK. 2) A lighting position above the auditorium, commonly with a catwalk above it to access lighting equipment and electrical systems is known in Dutch as a Zaalbrug. 

BUMP 

A flash or sudden jump in light level (a snap cue) (see also FLASH BUTTON).

BUMP CUE 

A lighting cue that instantly bumps the lighting up to a brighter level. Usually at the end of a musical number to draw applause. 

BURNT OUT 

A colored gel that has lost its color or melted through due to excessive heat in front of a lantern. Dark blues and greens etc. are most susceptible, and may need replacing during a long run. 

C CLAMP / C-CLAMP 

US equivalent of the UK Hook Clamp. Requires a spanner/wrench to tighten. Known as a PARROT CLAMP in the US film business. 

CALL 

1) A notification of a working session (eg a Rehearsal Call, Band Call, Photo Call) 2) The period of time to which the above call refers. (eg "Your call for tomorrow nights show is 6.55pm") 3) A request for an actor to come to the stage because an entrance is imminent (these are courtesy calls and should not be relied on by actors - eg "This is your call for the finale Mr Smith and Miss Jones") 4) An acknowledgement of applause (eg Curtain Call) 5) The DSM on the book is said to be "calling the cues". 6) The Colour Call is a list of lighting gel required for the lighting rig. 7) The Final Call is also known as The Half - 35 minutes before the performance starts, and the last time when the cast and crew should be in the theater. 

CALLING THE SHOW 

The process of giving verbal cues to the lighting, sound, fly operators and stage crew during the performance. Usually done from the prompt corner by the DSM or Stage Manager over cans.

CLEAR-COM 

1) Headset earpiece, microphone and beltpack used for communication and coordination of technical departments during a performance. (e.g. "Electrics on cans", "Going off cans", "Quiet on cans!"). A commonly used system in the UK is produced by Canford Audio under the TechPro brand. In the USA, ClearCom is commonly used. 2) Any headphones. 3) Short for PARCANs. 

CHANNEL 

A complete control path for signals in lighting or sound equipment. In a lighting desk, the channels are directly controllable by the lighting operator. Within the desk, the channels are 'patched' to a dimmer or dimmers which the desk then sends a signal to depending on the level of the channel. 

CHASE 

A repeated sequence of changing lighting states. A chase can be produced easily by the effects functions of a computerized lighting desk. There are standalone units designed to chase lighting circuits electronically in time to music (sound to light) or mechanically as a repeated sequence (as used in early neon signs). 

CHEAT SHEET 

A smaller version of the lighting plan, used by the lighting designer during the lighting plot. Also known as a Dimmer Layout or Magic Sheet. 

MASTER ELECTRICIAN 

The senior member of the theater's stage lighting team, although not necessarily the lighting designer. Known in the US as MASTER ELECTRICIAN. In common with many theater jobs, the actual duties of the Chief Electrician vary from theater to theater. Some chiefs are responsible for electrical maintenance of the building, some design the lighting for nearly every in-house production, some design no lighting at all, some have a team of eight staff under them, some have two. Many theaters employ casual staff to assist on lighting rigging sessions. Some theaters have a separate sound department, smaller venues have the lighting team also running sound for shows (and doing sound design for some).

CIRCUIT 

1) The means by which a lantern is connected to a dimmer or patch panel. Numbered for reference. In a fully patchable system, the circuit number (also known as socket number) can be connected to any of a wide range of dimmers. 2) A complete electrical 'loop' around which current can flow. 

COLOR CHANGER (Scroller) 

1) Scroller, where a long string of up to 16 colors is passed horizontally in front of a lantern. Remotely controlled by the lighting desk. Some scrollers have cooling fans to prolong the life of the gel string. Stronger colors will burn out faster without cooling, or if the focus of the beam is concentrated on the gel. If colors aren't lasting very long in scrollers, try changing the focus of the lantern. HEAT SHIELD clear gel should be used between the lens and the color scroller to absorb some of the heat. 2) Wheel : Electrically or manually operated disc which is fitted to the front of a lantern with several apertures holding different color filters which can be selected to enable color changes. Can also be selected to run continuously. 3) Semaphore, where framed colors are electrically lowered into place in front of the lantern. Remotely controllable. Can perform additive color mixing by lowering two colors into position at the same time. 4) Magazine : Manual semaphore-type device used on the front of a followspot. Known in the USA as a BOOMERANG. 

COLOR FRAME (Gel Frame) 

(or Gel Frame) A frame which holds the color filter in the guides at the front of a lantern. Many different sizes of frames are needed for the different lanterns. 

COLOR MIXING 

Combining the effects of two or more lighting gels: 1) Additive : Focusing two differently coloured beams of light onto the same area (eg Cyc Floods). Combining colors in this way adds the colors together, eventually arriving at white. The three primary colors additively mix to form white, as do the complementary colours. 2) Subtractive : Placing two different gels in front of the same lantern. Subtractive mixing is used to obtain a color effect that is not available from stock or from manufacturers. Because the ranges of color are so

wide, the need for subtractive mixing is reducing. Combining colors in this way reduces the light towards blackness. The three primary colors mix subtractively to form black (or to block all the lights) 

CRESCENT WRENCH 

(US) A open ended adjustable hand wrench originally produced by the Crescent Tool Co. Known as a C-WRENCH. 

CROSSFADE 

Bringing another lighting state up to completely replace the current lighting state. Also applies to sound effects / music. Sometimes abbreviated to Xfade or XF. 

CUE 

1) The command given to technical departments to carry out a particular operation. E.g. Fly Cue or Sound Cue. Normally given by stage management, but may be taken directly from the action (i.e. a Visual Cue). 2) Any signal (spoken line, action or count) that indicates another action should follow (i.e. the actors' cue to enter is when the Maid says "I hear someone coming! Quick - Hide!") 

CUE TO CUE 

(also known as 'Topping and Tailing') Cutting out action and dialogue between cues during a technical rehearsal, to save time. (e.g. "OK, can I stop you there - we'll now jump to the end of this scene. We'll pick it up from Simon's line "And from then on it was all downhill" in a moment. OK - we're all set - when you're ready please.") 

CUEING 

There is a standard sequence for giving verbal cues: -'Stand-by Sound Cue 19' (Stand-by first) -'Sound Cue 19 Go' (Go last). 

CYC LIGHTS 

Fixtures that illuminate the Cyclorama.

DIFFUSION 

A diffusing filter used to soften the edges of a light beam. Frosts are commonly used in profiles in front of house positions to achieve the same beam edge quality in all lanterns. Different strengths of diffusion frost are available from many color filter manufacturers. Rosco makes a range called Hamburg Frost - see link below. See also SILK. 

DIGITAL DIMMER 

The new generation of dimmers that can respond directly to the digital multiplexed output of the lighting desk. The technology also permits the dimmer to report faults and other data back to the control board. 

DIMMER RACK 

A number of individual lighting dimmer circuits built into a single case. Consists of a single power input, a lighting control (DMX512) input and sockets to connect lanterns. A dimmer rack can be set to respond to any control channel by setting its start address (known as "addressing" the rack). 

DMX Terminator 

A DMX terminator is a 3 or 5 pin XLR connector which is used at the end of a DMX run to absorb the data signal to stop it being reflected back along the DMX cable. The terminator is very easy to make, and consists of a 120 Ohm half-watt resistor soldered between pins 2 and 3 of the XLR connector. A DMX run should always be terminated, and although the system may work without one, continued operation cannot be guaranteed. A system with poor quality DMX cable (or cable of a long run) will require termination in order to operate correctly. 

DMX512 

Short for Digital Multiplex. See MULTIPLEXED (MUX) SIGNAL. 

DOWNLIGHT 

A light from directly above the acting area.

DRESS LIGHTING 

Providing a low level of lights to an open stage while the audience enters the house up until the performance starts. Also known as PRESET.