ACOUSTICAL REFLECTOR PANEL: A reflective panel hung in the auditorium, generally above the audience, that is used to direct sound into desired zones. Often decorative in nature.
ACOUSTICS: The science of, and study of sound. The acoustics of a room or space depend on its size and shape and the amount and position of sound-absorbing and sound reflecting materials.
ACT CURTAIN: A curtain (sometimes designed for a specific show) that is opened to signal the beginning of a performance. The Front Curtain is often used for this purpose.
ADVANCE BAR: A lighting bar hung from the auditorium ceiling, usually fairly close to the stage, to provide steep frontal illumination.
AMBIENT LIGHT: General indirect light, produced by reflection from the stage, scenery, or by scatter from lanterns.
AMPHITHEATRE: Stepped banks of seating surrounding an arena. Also used to describe one of the tiers of a multi-level auditorium.
APRON: The portion of stage that extends beyond the proscenium opening.
ARBOR: A carriage or rack that contains weights, usually flame cut steel or cast iron, in sufficient quantity to balance a load.
ARBOR PIT: An area located below an opening in the stage floor that permits greater travel for counterweight arbors and pipe battens.
ARENA STAGE: A performance space with seating all round the performers. Examples include theaters, basketball courts, and indoor rodeos.
ASPECT RATIO : Describes width of a picture to the height. The NTSC standard is 4:3. The current HDTV standard is 16:9. Modern movies range from 1.66:1 to 2.4:1. By far the most common are 1.85:1 and 2.35:1.
BACK LIGHT: Light from behind the actor or a piece of scenery. It is highly sculptural light which separates the actor from the background.
BACKDROP (backcloth): A painted or black cloth hung down behind the acting area hide the backstage and to mark the back of the area in which acting takes place. See also Blacks.
BACKING: Scenery used behind, and limiting the view of the audience through an opening (e.g. doorway or window) in a set. See also masking.
BAR: A tube, pipe or barrel for holding spotlights.
BARRE: A horizontal rail, usually of wood, used by ballet dancers when practicing.
BARREL: Length of metal pipe, suspended on a set of lines, to which scenery may be attached by means of snatch lines instead of being tied directly to the suspension lines. It is a standard part in a unit of the counterweight system.
BIO BOX: Room from which light, sound, projection and effects are operated — often soundproof.
BLACKOUT: A fast shutdown of all lighting to complete darkness.
BLACKS: Curtains hung both to mask the back-stage area and to shape the on-stage area. Normally made of wool surge.
BLEACHER SEATING: Stepped seating blocks which can be retracted for storage and to clear a flat floor.
BOBBIN: Cylindrical carrier for the suspension and movement of draw curtains on a horizontal track.
BORDER: A pelmet used to mask the line of sight over a setting and to hide the flies lighting battens, etc.
BRAIL (BRAIL LINE): Line used to pull and retain any piece of hanging scenery or property from the position it would occupy if left hanging free.
BRIDLE: A short length of cable or chain used to distribute the stress on a barrel at a suspension point.
BRIGHTNESS : A viewer’s subjective response to a display’s luminance.
CANVAS (CANVASING): The fabric used to form a cloth or to cover a flat etc.
CATWALK: An immobile platform above the stage that reaches from one end of the stage to the other, used to gain access to the stage equipment.
COUNTERWEIGHTS (COUNTERWEIGHT SYSTEM): Mechanical system for flying scenery in which the weight of the pieces of scenery is balanced by adjustable weights in a cradle running up and down in guides in a frame normally at the side of the stage. Double purchase systems gear the movement of a counterweight to half that of the scenery it is supporting.
CONTRAST RATIO : The contrast ratio is a figure used to measure the luminance difference between the brightest white and the darkest black.
CURTAIN: In addition to its normal definition relating to draperies, a term used to indicate the start or end of a performance such as “Five minutes to curtain up” (five minutes to the start of the performance).
CURTAIN LINE: The imaginary line across the stage immediately behind the proscenium which marks the position of the house tabs when closed.
CURTAIN TRACK: Rails from which draw tabs are hung and along which the runners or bobbins travel when the curtains are moved; the track may be fixed or flown.
CUT CLOTH: A cloth which has a part cut out to reveal another cloth set behind, the cut-out portion is often filled with gauze.
CYCLORAMA: Plain, curved, stretched cloth or rigid structure used as a background to a setting, giving an illusion of infinity.
DEAD: The predetermined level to which a suspended scenic piece is raised or lowered to take up its correct position in the setting.
DEAD BLACKOUT: Complete darkness on stage, used to hide scenery changes or to create dramatic effect.
DOWNLIGHT: Light from above the actor, the beam perpendicular to the stage floor. Can be use as a colour wash without the light directly hitting the scenery.
DOWNSTAGE: Portions of a stage nearest the audience.
DRAPERIES (DRAPES): Any unspecified fabric hanging in folds as a scene or part of a scene, especially curtaining fabrics such as woolens, velvets etc.
DUTCHMAN: Thin strips of cloth used to mask cracks between flats.
FALSE PROSCENIUM: Arrangement of scenery forming an arch immediately behind the proscenium opening. See also teaser and tormentor.
FESTOON TABS (CURTAINS): Curtains fixed at the top and raised (opened) by drawing the bottom upwards towards the top and/or sides.
FIRE CURTAIN: A non-flammable curtain hung directly behind the proscenium that protects the audience from fire or smoke emitting from the stage.
FIRST ELECTRIC: The first row of lanterns hung on a bar behind the proscenium.
FLOODLIGHT: A lantern that projects a diffused, un-focused beam of light. Used for general illumination.
FLOWN: Suspended on lines.
FOCUS: To direct and “lock off” a lantern in its specified stage area.
FOLLOW SPOT: A hand operated lantern mounted on a swivel stand that emits a high intensity beam of light used to follow an actor on stage.
FOOT-LAMBERT: A foot-lambert or footlambert (fL, sometimes fl or ft-L) is a unit of luminance in U.S. customary units and some other unit systems. A foot-lambert equals 1/π candela per square foot, or 3.426 candela per square meter (the corresponding SI unit). The foot-lambert is named after Johann Heinrich Lambert (1728–1777), a Swiss-German mathematician, physicist and astronomer. It is rarely used by electrical and lighting engineers, in favor of the candela per square foot or candela per square meter.
We often use fL to measure cinema screen brightness. It is particularly useful to measure screen brightness before and after cinema screen cleaning to better understand how much improvement in brightness and consequently, patron experience, results from the cinema screen cleaning process.
FOOTLIGHTS: Normally found on the forestage pointing up stage, can be permanent or mobile.
FLOOR CLOTH: A heavy piece of muslin used to cover the stage floor.
FLY: To lift above the level of the stage floor by means of sets of lines from the grid. The term flies is also used as an abbreviation for fly gallery.
FLY GALLERY (FLYING GALLERY): A gallery extending along a side wall of the stage, some distance above the stage floor, from which ropes used in flying scenery are operated. Also Known as a fly floor. The fly galleries are usually referred to collectively as the flys.
FLY RAIL: Heavy rail along the on-stage side of a fly gallery, equipped with cleats to which the ropes can be- made secure. Also called pin rail.
FLY TOWER: The space above a stage in which scenery can be flown out of sight of the audience.
FLYING IRON: Metal plate with a hinged ring used for scenery suspension.
FOLLOW SPOT: A high intensity spotlight controlled and directed by an operator.
FORESTAGE: Portion of the stage floor in front of the curtain line.
FRAMED CLOTH: Scenic cloth battened all around.
FRENCH FLAT: Arrangement of several flats battened together and flown as one unit on a set of lines.
FRONT CLOTH: Sometimes a painted cloth is brought down near to the house curtain for a front scene to be played on the forestage. This front cloth usually masks scene changes behind it.
FRONT LIGHT: A light coming from downstage of the subject, generally brought in 45 degrees off full front.
FRONT OF HOUSE: Areas of a theatre on the audience side of the proscenium wall or stage area are called FOH.
GAIN: A measurement made to determined the screen reflectance. The higher the number, the greater light is transmitted to the audience.
GAUZE (GAUZE CLOTH): Flat curtain of fine mesh mosquito netting or similar fabric, either painted or unpainted, which when lit solely from the front appears to be opaque, but when lit from behind becomes transparent. It is used for transformation scene or other illusions. A fabric known as “Sharks tooth gauze” is also used for this purpose.
GRID (GRIDIRON): Framework of steel or wooden beams over the stage used to support the sets of lines employed in flying scenery.
HEMPS: The term is usually employed to signify lines used for flying scenery which are made from vegetable fibre as distinct from the steel wire ropes used in the counterweight system. Hemp lines are hauled up manually and tied off on a cleat on the fly rail. A hemp house is a stage equipped with these hand operated “hemp sets” and no counterweights.
HOUSE: The part of the theatre where the audience sits.
HOUSE LIGHTS: Lights used to illuminate the area where the audience sits.
HOUSE TABS (CURTAIN): The main curtains between stage and audience, normally placed immediately behind the proscenium.
HEAD BLOCK: Device compromising three or more sheaves set together either in line or parallel to each other on a common shaft and attached to the grid directly above the fly rail. The lines from the three or more loftblocks in a set are brought together at the lead block and pass on down to the fly rail cleat in a hemp set or to the weight cradle in a counterweight set.
LANTERN: A stage-light.
LEGS: Narrow curtains or cloth that hang vertically on the sides of the stage to mask the backstage area. Also called tormentors.
LENS SPEED: The ability of a lens to pass light. Expressed in a ratio, it is the focal length of the lens divided by the effective diameter of the lens. A fast lens passes more light and gets a lower rating.
LIFT: Section of stage floor that can be raised or lowered or tilted to provide differing levels of acting area, or to enable changes of setting to be made in the stage basement. Also Known as a bridge.
LIGHT CURTAIN: A batten of low voltage narrow angle lamps, usually 8 to 10, wired in series, used to create a narrow strip of intense light.
LOCKING RAIL: In a counter weight system the handling rope passes through a rope lock attached to a locking rail which runs the length of the counterweight wall frame.
LOFT BLOCK (GRID PULLEY): Sheaf in a metal frame bolted to the grid and used to pass a suspension line; there is one block for each line in a set. See also Set of lines.
LUMEN: The quantity of visible light falling on a 1 square foot surface of a sphere 1 foot in radius as radiated by a source of 1 standard candle. This specification is often used to rate the light output of video projectors. Look for ANSI lumen ratings, it is a standardized measurement.
MASK: To hide any equipment or offstage area through the use of curtains, flats, etc.
MASKING (MASKING PIECE): A piece of scenery, not necessarily painted, used to cut off from the view of the audience any part of the stage space which should not be scene.
MICRO PERFORATION: Smaller perforation holes allowing sound to pass directly through the screen. Hole diameter typically 0.8mm. Mainly used in small theatres where the audience is near the screen.
OVERHANGING: Rigging a spotlight standing above a lighting bar rather than suspending it below the bar.
PERCH: Position above stage level on the stage side of the proscenium wall either side of the opening.
PERMANENT MASKING: Show portal, or teaser and tormentors, or similar arrangements of masking pieces which remain in place throughout a performance, regardless of scene changes.
PIT: The area below the front of the stage. May be used to house the orchestra. Also called the Orchestra Pit.
PLASTER LINE: An imaginary line that runs across the proscenium along the upstage side of the proscenium wall. This line is-used by designers and technicians to position various technical elements in the theatre.
PROSCENIUM ARCH (PROS): The theoretical “fourth wall” of a stage. Comprising the proscenium opening and its surrounding.
PROSCENIUM DOORS: Doors on either side of the stage leading onto a forestage in front of the house curtain.
RESOLUTION: The limit of a display’s ability to present fine detail. “Optical resolution” is usually the number of lines seen, “video resolution” is usually the number of “line pairs” seen.
REVEAL (THICKNESS): Piece of timber or other material attached to the edge of an opening (e.g. a doorway) to give the effect of depth or thickness.
REVOLVE: Circular table forming a permanent part of the stage floor or standing upon it, on which scenery can be set for quick changing of scene or for creating various effects. Sometimes the revolve is formed of two or three rings and a centre, capable of independent or simultaneous movement, differing speeds and opposite directions. It can be turned through 360 degree either manually or by motor.
ROLLER: Where there is no flying space over the stage a backdrop can be rolled and is than called a roller or roll drop.
ROPE LOCK: The handling rope of a counterweight set passes through a “rope lock” which when locked prevents any further movement.
ROTARY LEG UNIT: Device for suspending a leg so that the angle of the leg in relation to the proscenium can be varied.
RUNNER: A length of stage flooring that can be drawn off sideways leaving a long narrow opening(cut) through which a cloth or flat may be raised.
RUNNER: Length of carpet used offstage to reduce back stage noise.
SAFETY CHAIN: A steel chain used to attach hanging equipment to the support structure as a safety support in case of failure of the primary hanging support (clamp etc.).
SAFETY CURTAIN (fire curtain / iron): Screen or shutter comprising a steel framework faced with sheet steel and mineral fibre fabric, mounted immediately behind the proscenium opening and fitted with a mechanism for raising it clear of the top of the proscenium arch and with a quick release device to allow it to descend by gravity in the event of fire on the stage.
SCREEN: What the picture is projected onto. The screen is more important when it comes to front projectors, when the screen must be bought separately.
SCRIM: Coarse woven Hessian, or similar material used in scenery construction.
SET OF LINES: Unit group of suspension lines hanging from the grid for the attachment and flying of scenery; there are usually three or four lines in a set. See also counterweights.
SHEAVE: Grooved wheel (pulley) over which a line may be passed.
SHOT-BAG: Similar to a sandbag but smaller and filled with lead-shot.
SIDELIGHT: Light from the side of an actor facing the audience. Side lighting is often used in dance, as it emphasizes the entire body and movement.
SIGHT LINES: Imaginary lines of sight that determine what is visible to the audience on stage and what is not.
SINGLE PURCHASE: A suspension system where there is no gearing of pulleys. The counterweight and its travel will be the same as that of the object which is suspended.
SPOT BLOCK: Pulley fixed to the grid specially for a spot line.
SPOT LINE: Single suspension line specially rigged from the grid to fly a piece of scenery or stage property which cannot be handled by the regular lines.
STAGE CLOTH: Large piece of canvas, used to cover the stage floor, often painted to represent paving etc.
SURROUND (CURTAINS): Set of legs (ordinary pleated curtains) hung from a curved or angled bar to form the sides and background to an acting area.
SWAG: Looped-up curtain, border or leg.
SWATCH: A small piece of fabric or paint used to demonstrate the colour and/or texture of the material being used.
SWIVEL ARM: Device for suspending a leg so that the angle of the leg in relation to the proscenium can be varied (Rotary Leg Unit).
TAB WARMERS: Light on the house curtain before the beginning of a show or act.
TEASER: Border hung between the tormentors, just between the proscenium opening. See also permanent masking.
THROW DISTANCE: The distance from the screen surface to a video display device. This is an important number used in the installation of a video display.
THROW LINE: Length of cord attached by a grummet to a piece of scenery and used to secure the piece to an adjacent piece.
THROW-LINE CLEAT: Metal fitting attached to a flat or other piece, round which the throw-line is passed when securing adjacent pieces together.
TORMENTOR: Substantial wing, not necessarily painted, placed immediately behind the proscenium opening, to mask the off stage edges of the setting etc. See also permanent masking.
TRACK (CURTAIN TRACK): Rails from which curtains are hung and along which they may move.
TRAPS: Removable areas of the stage floor that allow access to the area underneath the stage. Special purpose traps are grave traps, dip traps and star traps.
TRAVELLER: A curtain that can open to the sides of the stage.
TUMBLER: Batten on roller fixed to the bottom edge of a cloth, about which the cloth can be rolled upwards when not in use.
VIEWING ANGLE: The angle at which a person is able to stand in regard to an image and still be able to see the entire image without distortion.
WIDESCREEN: Term used to describe a picture in which the aspect ratio is wider than the NTSC standard of 4:3/1.33:1. Almost all movies made nowadays are shot in some widescreen format. To solve the problem of different aspect ratios, several different techniques can be used. Among them are anamorphic squeezing, letterboxing, and Pan and Scanning.
WINGS: Offstage spaces to left and right of the acting area.
WINGSET (Backcloth-and-wing set): Setting comprising backcloth (or cyclorama) and pairs of wings with borders above. Sometimes cut cloths are used in the place of wings and borders (e.g. a woodland scene).
WORK LIGHTS: Lights used for general illumination of the stage when not in performance.