THEATRICAL, LIGHTING & RIGGING TERMS

A

ACHROMATIC LENS: A lens which transmits light without separating it into its spectral colors.

ACT CURTAIN: Also called Front Curtain or Main Curtain. The curtain closest to the proscenium that opens and closesto expose the stage area to the audience.

ACETATE: Thin clear sheet plastic made from acetic acid.

ACRYLIC: Clear or translucent sheet plastic made from a salt of acrylic acid.

ADDITIVE PROCESS: The process of producing colors by mixing light of the additive primaries (red, blue, green) invarious proportions.

AIR CASTER: A device which consists of a neoprene ‘0” which inflates to a seal with the floor and a plenum chamber inthe center of the “0” in which air pressure builds up to exceed the load, thereby causing the device to rise, break the sealand float the device. Properties include almost frictionless horizontal movement, firm contact with the floor when unitsettles in place, but they require very smooth nonporous surface.

ALBEDO: The reflective ability of a surface compared to the amount of light it receives.

ALZAK: A patented method of processing aluminum surfaces to increase reflectance andmany lighting instrument reflectors.

AMPERE: Unit of measure of electrical current.

to prevent deterioration. Used in

ANNEALING: A process in which wire is heated close to the melting point and thenpermitted to slowly cool. This usuallylowers the wires temper or tensile strength.

-APRON: The area of the stage that is in front of the proscenium.

APPARENT LIGHT SOURCE: The source of light to be assumed by the audience, such as the sun or a window.

ARBOR: A metal frame that holds the counterweights used to balance the weight of flown scenery. Also referred to as theARBOR CRADLE or CARRIAGE.

ARBOR PIT: A pit located under the path of the flying system counterweight carriages, or arbors, to allow the arbors to gobelow the level of the stage floor and the battens to fly out higher than if the travel ended at the stage floor.

ARC LIGHT: See CARBON ARC LAMP.

AUTOTRANSFORMER: A toridal wound transformer with a single winding around an iron core which is both primary andsecondary. In theatrical uses it has a brush which can be rotated around the core varying the voltage applied to the circuit.

AUDITORIUM: The area where the audience is seated. Also called the HOUSE.

AUDITORIUM LIGHTING: Lighting for the area used for seating. Also called HOUSELIGHTING.

AUGER: A cutting bit, used for drilling holes.

A.W.G.: American Wire Gauge. A method of specifying wire diameter.

AWL: Sharp pointed tool used for punching holes in canvas or leather.

B

BABY SPOT: A small spot light, usually 400 watts or less and which usually has a lens diameter of 5 inches or less.

BACKFLAP HINGE: A type of hinge used for hinging scenery. The loose pin type permits the scenery on which it isinstalled to be taken apart when the wire pin connecting the halves is removed. In the tight pin type, the connecting pinis permanently installed.

BACKING LIGHTS: Any instruments used to illuminate set pieces behind openings in the set.

BACK LIGHTING: Lighting from upstage and usually above the performer.

BACK PACKS: Metal plates installed on the operating line of a traveler curtain between the carriers to gather folds off stageas the curtain is opened or closed.

BACKSAW: A hand saw with a reinforcing strip on the back edge. Commonly used in a miter box.

BACK SPLICE: The rope strands are crowned, then tucked back, over and under as in a short splice.

BAG A LINE: To install a sandbag either on a free line or on a pipe to compensate for weight removed from a pipe. Alsoused to keep a free line from going slack and pulling back thru the blocks. Shortened to “BAG II’“.

BALLAST: A circuit element that serves to limit an electric current or to provide astarting voltage, as in certain types oflamps, such as in fluorescent fixtures.

BALL PEEN HAMMER: A hammer with a round head, in place of the claws. Frequently used for metal work.

BALCONY LIGHTS: Lights mounted in or on the front of the balcony, used to light the downstage areas.

BAND SAW: A power saw, having a continuous blade, and commonly used for fancycutting, such as curves and scrolls.

BARNDOOR( A type of framing device, with two or four hinged metal pieces mounted on the front of a lightingi n s t r u m e n t .

BASE: 1) The part of an incandescent lamp which attaches it to the socket. 2) A metal disc attached to a spotlight or boompipe to enable it to sit flat on the floor.

BATTEN: A steel pipe or wooden bar used to support scenery curtains and lights. Usually suspended from the grid or roofstructure.

BATTEN CLAMP: 1) A piece of stage hardware the top of which clamps onto a pipe batten and the bottom clamps on thewooden batten of a drop to hold it. 2) A piece of rigging hardware used to attach the batten to its hanging cable.

BEAM ANGLE: See BEAM WIDTH.

BEAM LIGHT: A light mounted in a false beam or elsewhere in the auditorium ceiling and used to light the downstage areas.

BEAM PROJECTOR: A floodlight with narrow beam characteristics, has a parabolicreflector with the lamp or light sourceat the focus.

BEAM WIDTH: The angle, measured in a horizontal plane, between the directions at which the intensity of a light beam isone-half its maximum value. Also called BEAM ANGLE.

BEAVER BOARD or UPSON BOARD: A laminated cardboard.

2

BECKET: A rope eye used for the hook of a pulley. Also a rope grommet used as arow-lock, any small rope strap used asa handle.

BELAYING PIN: A wood or metal pin designed to be inserted-in a hole in a pin rail to which running rigging is secured.

BEVEL: To cut the edge of a piece of lumber at an angle other than 90 degrees.

BIGHT: The bend of a line, rope or cable.

BIPOST LAMP: A lamp having two prongs, which is inserted by pushing straight into the socket.

BIT: The metal end of a screwdriver.

BLACKLIGHT: See ultraviolet light.

BLEEDING LINE: When cable is overloaded, the lubricant in the cable will be squeezed out, and run excessively.

BLOCK: A pulley or several pulleys in a frame.

BOARD FOOT: A unit of measure of lumber. Each unit is 1” thick, 12” wide and 12” long.

BOBBINET: A lightweight cotton netting.

BOLT: A metal rod for fastening objects together that usually has a head at one end and a screw thread at the other and issecured with a nut.

BOOK: To fold two hinged flats together.

BORDER: Strips of fabric hung horizontally above the stage to mask overhead space and equipment.

BORDERLIGHT: A striplight (usually in 6’ sections), usually as long as the proscenium is wide, hung from overhead andused for general illumination. Frequently found in older theatres hung every 10 to 12 feet.

BOOMERANG: 1) A color changer on the front of a light. 2) A multilevel moveableplatform for workmen, frequently usedby painters.

BOOM: Pipe mounted horizontally to mount lights.

BRACE and BIT: A tool for boring holes in lumber.

BRACE CLEAT: A unit of stage hardware to which the upper end of a stage brace can be attached. It is usually screwedto the stiles of a flat.

BRAD: A small wire nail.

BREAKING STRENGTH or ULTIMATE STRENGTH: Is the load at which a tensile failure will occur in a component.

BREAST LINE: Line used to drag or breast a piece of hanging scenery into an eccentric position or out the way of anotherset piece.

BRIDLE: Means of dividing the load to two pick-up points.

BRIDGE: See LIGHT BRIDGE.

BRILLIANCE: Intensity or amount of light.

BROAD: A wide angle, high intensity lighting instrument. Frequently has more than one light source.

BULB: See ENVELOPE.

BUTT JOINT: TWO pieces squared off and joined at a right angle.

C

CANVAS: A coarse, heavyweight woven cotton or flax fabric.

CARBON ARC LAMP: An arc lamp or light in which an electric current flows between two electrodes of pure carbonresulting in incandescence at one or both electrodes and some light from the luminescence of the arc.

CARRIER: Rollers in a traveler track to which the curtains are tied. First carrier is called the MASTER CARRIER and hasprovision to attach the operating line(s).

CATWALK: A steel structure over the stage and/or the audience area used by stage personnel to cross from one side to theother. Also used to suspend lighting instruments.

C-CLAMP: A C-shaped clamp used to attach lighting instruments to pipe battens.

CEILING PLATE: A piece of stage hardware, composed of a flat metal plate with a ring attached. It is installed on sceneryto be flown, particularly ceilings, and attached to the ropes used for that purpose.

CHEAT: To focus a light slightly off its intended location. Frequently to avoid a spill.

CHISEL: A flat tool with a cutting edge on one end and a handle on the other. It is generally used for gouging lumber.

CHOKER: Sling, wire rope with eyes spliced on each end. Is used to lift load.

CHROMA: The purity of hue of a color, saturation, freedom of additive mixture of white. Black, gray and white do not haveany chroma.

CHROMATIC ABERRATION: Colored rings or rainbows caused by unequal refractive characteristics of a lens or reflector.

CHUCK: A device on a drill or brace for holding bits or drills.

CIRCULAR SAW: A large, power saw with a round blade used for general cutting and ripping in shop work. Can be eitherof hand held or table type.

CIRCUIT BREAKER: A protective device used in electrical circuits to protect from overloads and short circuits which mightcause damage to the wiring, people or equipment. See FUSE.

CLAW HAMMER: A hammer with a pounding surface on one side of the head and two claw shaped projections on the otherside. The claws can be straight or curved.

CLEW: A plate of metal with holes in it used for connecting several lines so that they can be managed as a set or unit.

CLOUT NAIL: A wedged shaped nail of soft malleable metal which is used to assemble flats because it clinches (bends over)when driven through to the pounding surface.

COLD CHISEL: A tempered steel tool used to cut metal or stone.

COLOR TEMPERATURE: The temperature in degrees Kelvin to which a blackbody is heated to give essentially the samespectral distribution as the light source being measured.

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COLOR WHEEL: A circular device with several holes in which color media is mounted attached to the front of a spotlightand can be rotated to change colors.

COMPANY SWITCH: A large capacity disconnect box located backstage, used for the connection of Portable dimmer hanksor other temporary electrical equipment.

COMPLEMENTARY COLOR: Any two colors which when mixed tend to produce white. Colors opposite on the colorwheel. Pigment primary colors are light complementary colors and vise versa.

CONCAVE: A surface which is curved inward.

CONCAVO-CONVEX LENS: A lens which is curved inward on one side and outward on the other.

CONCERT BORDER: Borderlights mounted on an electric pipe just upstage of the proscenium.

CONDENSING LENS: One which brings light rays together.

CONSTANT: A stage circuit which always has electrical power supplied to it. See NONDIM.

CONTACTOR: A large electromagnetic switch capable of being remotely controlled

CONTOUR CURTAIN: Permanently tied at the top and with individual vertical control lines spaced at intervals across thecurtain, passed through rings sewn in the curtain and fastened at the bottom, designs or “contours” are made by raisingthe lines to various heights.

CONVEX: A surface which is curved outward.

COPING SAW: A hand saw with a thin narrow blade, held in a frame, used for fine scroll work in thin wood, etc.

CORNER BLOCK: A piece of plywood cut in the shape of a right triangle with 10” sides. Used to reinforce right anglejoints. Frequently used on the comer joint of flats.

CORNER PLATE: An L-shaped plate of metal, with screw holes, used to connect comers of scenery frames.

CORRUGATED FASTENER: A fluted piece of metal, with points on one side used to hold two adjoining pieces of lumbertogether.

COUNTERWEIGHT SYSTEM: A device for flying scenery by the use of weights, pulleys, blocks, ropes and arbors. Itoperates by using the weights to offset the weight of the scenery, and cause the scenery to rise or “fly”.

COUNTERWEIGHTS: The weights placed in a arbor or carriage and used to counterbalance loads placed on battens thatare moved vertically.

COUNTERWEIGHT CARRIAGE: See ARBOR.

CRESCENT WRENCH: Trade name for a wrench in which the opening between the jaws is adjustable, and the jawsthemselves are set at an angle to the handle.

CROSSCUT SAW: A hand saw with finer teeth than a rip saw, designed for cutting across the grain of lumber.

CROSBY: Trade name for a U-shaped wire rope clip.

CROSS FADE: To fade from one lighting setup or “look” to another without dimming out.

CUE: A visual or audible signal from the stage manager to execute a predetermined change of lights, sound or scenery.

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CURRENT or CURRENT FLOW: The net transfer of electric charge per unit time. Also referred to as ELECTRICCURRENT.

CUT DROP: A drop in which patterns or designs have been cut.

CYCLORAMA: A large curtain of canvas, muslin or other material, either in one piece (preferred) or in sections, hung ina U-shape, usually the most upstage drape. Frequently light blue in color.

D

DAD0 JOINT: The end of one piece of lumber fits into a slot cut into the side of another.

DEAD-FRONT: Having no exposed current-carrying parts.

DEAD HUNG: Battens or similar equipment that is permanently supported from the grid and cannot be easily raised orlowered.

DESIGN FACTOR: See SAFETY FACTOR.

DIAGONAL CUTTERS or DIAGONALS: Pliers with sharp inside edges used for cutting wire. Also referred to as DIKES.

DICHROIC MIRROR or FILTER: A glass surface coated with a special metal film that reflects certain colors of light whileallowing others to pass though. Frequently used to make lamp reflectors which allow the infrared (heat) wavelengths passout the back while reflecting the visible wavelengths.

DIFFRACTION: The effect of a light beam changing direction as it passes through a substance.

DIFFUSE: Reflect or dissipate in all directions.

DIKES: See DIAGONAL CUTl-ERS.

DIh3: To change the amount of illumination, either by increasing (dim up) or decreasing (dim down) it.

DIMMER: Any means for controlling the light output from a lamp.

DONKEY: Electric winch.

DOPE: A mixture of glue and whiting that sticks to canvas.

DOUBLE PURCHASE COUNTERWEIGHT SYSTEM: An arrangement of pulleys and cables used to reduce the traveldistance of a counterweight carriage or arbor. Requires twice the counterweight for a given load as a single purchasesystem and batten travel is twice arbor travel.

DUYETYN: A soft, sturdy twill weave fabric with a napped surface.

DOWELED JOINT: Matched holes are drilled in two pieces of lumber and hardwood pegs, called dowels, are covered withglue and inserted in the holes.

DOWN LIGHT: Light focused straight down on to the performing area.

DOWNSTAGE: Toward the audience.

DOUSER: A device placed in front of, or installed inside of, a spotlight to vary the beam intensity, most commonly foundin foiiowspots.

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DRILL: A steel tool, with twisted fluting used to make holes in metal or wood.

DROP: A large unframed piece of material hung from a batten and with a lighter batten or chain at the bottom to keep it freeof wrinkles.

DUCK: A coarse, heavyweight woven cotton or linen fabric similar to canvas.

DUTCHMAN: 1) A strip of muslin or canvas glued over the junction of two scenic pieces to conceal the joint. 2) A systemof lenses mounted on the front of a spotlight for projection purposes.

E

EFFECTS MACHINE: A lens projection instrument designed to project moving effects.

ELASTIC LIMIT: Limit of stress above which a permanent deformation takes place in the material.

ELLIPSOIDAL: Stage light using an ellipsoidal reflector. Short for ellipsoidal reflector spot light.

ELLIPSOIDAL REFLECTOR: A reflector which has two focal points. When light is place at one focal point, light fallingon the surface of the reflector converges to the other focal point.

ELONGATION: Ability of a material to undergo deformation without rupture.

ENVELOPE: The glass part of a lamp. Sometimes called the BULB.

EYE or EYE SPLICE: A loop with or without a thimble formed in the end of a rope or cable.

F

FADE: To dim up or down. See CROSS FADE.

FALL: The part of the rope in a tackle rigging to which the power is applied to lift the load.

FALLS: A set of blocks reeved or laced, with cable or rope.

FIELD ANGLE: The angle in a horizontal plane, between the directions which contain 10% or more of the maximumcandlepower of the total field.

FILAMENT: A wire or coil of wire, usually tungsten, inside a bulb which gives off light when heated to incandescence bypassing a current through it.

FILL LIGHT: Light in addition to key light used to blend areas and/or reduce shadows.

FIRE CURTAIN: A non-flammable curtain immediately behind the proscenium, contained in the smoke pocket, used toprotect the audience from possible smoke and fire originating from the stage.

FLAT: A unit of scenery. Usually a rectangular frame of lumber covered with canvas or muslin.

FLEET ANGLE: Angle between position of a rope at the extreme end wrap on a drum, and a line drawn perpendicular tothe axis of the drum through the center of the nearest fixed sheave.

FLIPPER: A small flat (or piece of lumber) hinged to a larger piece of flat scenery.

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FLOODLIGHT: A lensless lighting instrument, usually with a large reflector and high wattage lamp, used for generalillumination.

FLOOR POCKET: A metal box mounted in the stage floor whose top is flush with the floor used to hold electrical or audiooutlets.

FLUORESCENCE: The property of absorbing radiation and emitting it as visible light.

FLIES: The space above the stage for flying scenery. See LOFT.

FLOATS: British term for footlights.

FLOAT A FLAT: To allow a flat to fall to the floor by allowing it to tip forward with its face down. The air resistance tothis surface forms a cushion which allows the flat to “float” down.

FLOOR PLATE: A metal plate with a ring attached, which can be countersunk into the stage floor. Used for tieing lines,attaching braces, etc.

FLY: To move scenery or similar devices vertically on the stage.

FLY GALLERY: A platform attached to the side wall of the stage from which the rigging devices are operated. Also calledfly floor.

FLY LOFT: The space above the grid and below the roof.

FOAM BOARD: A polystyrene sheet faced on either side by smooth white or brown kraft paper.

FOME-COR: Trade name for FOAM BOARD.

FOCAL LENGTH: The distance from the center of a lens to its focal point.

FOCAL POINT: The point at which parallel rays of light will converge after passing through a lens.

FOCUS: 1) The point at which the light source is placed in a reflector of a parabolic, elliptical or circular section. 2) Tooperate the focal adjustment of a spotlight. In popular usage to aim a lighting instrument.

F.O.H.: abbreviation for FRONT OF HOUSE.

FOLLOWSPOT: A spotlight designed for following the movements of a performer.

FOOT CANDLE: A unit of illumination. The illumination on a surface when there is a luminous flux of one lumen per onesquare foot. Also the illumination on a surface one foot from a source of one candle.

FOOT IRON: A piece of hardware used to fasten scenery to the stage floor. It can be a flat strip of metal, or an L-shapedpiece with the L either hinged or solid.

FOOTLIGHTS: One or more striplights placed downstage of the curtain line to provide general illumination. No longerfrequently used.

FOUL: Scenery or other stage equipment flown so as to become entangled with other curtains, lines, or equipment.

FOULING POLE: A pole used to free fouled items. Often a stage brace is used for this.

FRESNEL: A spotlight using a Fresnel lens.

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FRE!jNEX LENS: A lens which appears to be a piano-convex lens that has been cut into concentric circles and then pareddown to approximately the same thickness. Named for the French physicist Augustin Jean Fresnel (1788-1827).

FRONT OF HOUSE: Usually refers to lights mounted downstage of the proscenium.

FULLNESS: Folds in costumes or drapes.

FUSE: A protective device used in electrical circuits to protect from overloads and short circuits which might cause damageto the wiring, people or equipment. See CIRCUIT BREAKER.

G

GEL: Short for GELATINE. Genera! term which has to come to mean any type of color media for lights.

GELATINE: Thin, transparent sheets made of animal jelly and dye. Used at one time as color media for lights.

GENERAL lLLU&llNATION: Lighting a!! or most a!! of the stage from a number of instruments; as opposed to specificillumination.

GHOST LOAD: An additional load used to make a resistance dimmer operate properly when the capacity or wattage of theinstrument is smaller than the dimmer’s capacity, also required by some electronic dimmers for very small loads. Alsocalled a PHANTOM LOAD.

GOBO: A metal plate with a shaped opening, placed inside a spotlight to shape the beam. Also called a TEMPLATE.

GRID: The structural framework or beams over the stage used to support the rigging system. Short for GRIDIRON.

GROMMETS: Metal reinforcing eyelets through which a rope, cord or other fastening device may be passed.

GROUND: Electrical term for any conductor directly connected with the earth. Not to be cont%sed with the neutral whichis a current carrying conductor.-

GROUND CLOTH: A large piece of canvas duck used to cover the stage floor.

GROUND ROW: A low profile of scenery, usually designed to be self supporting.

GLUE GUN: Electric too! used to heat and apply hot glue.

H

HACKSAW: A small hand saw with fine teeth for cutting metal.

HALVED JOINT: One-half the thickness is removed from the ends of two pieces of lumber and then they are glued and/orscrewed together.

HAI\IRIERS: Driving tools. Common types for stage use are ball peen, claw, mallet and tack.

HANGER IRON: A strip of iron with a ring on one end which is bolted to scenery to be flown. The lines for flying areconnected to the ring. ??le strip may be straight, or have the end without the ring bent into a hook for supporting heavyscenic pieces.

HARD LIGHT: Lighting with sharp we!! defined shadows.

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HEAD BLOCK: The first sheave or pulley that is directly above the counterweight carriage, arbor, or winch with theprinciple function of changing the direction of travel of the lifting lines from vertical to horizontal.

HEADACHE BLOCK: The travel block of the multiple, or main load line.

_ HEADS Up: Warning call given when lowering in scenery, battens or when a tool or hardware is dropped from above.

HEMP SYSTEM: A system of hemp (now manila fiber) ropes used to raise and lower scenery.

H.I.D. LAMP’: High Intensity Discharge lamp. Shortened to H.I.D.

HIGH HAT: See TOP HAT.

HIGH TBIM: Highest point to which a piece of scenery is flown. Usually the point at which the piece of scenery is out ofsight.

HINGES: Pieces of hardware composed of two flaps of metal (halves) fastened in the middle so that they swing freely. Usedfor pieces of scenery which must swing, such as doors, or fold. Most commonly used for stage work are backflaps (looseand tight pin) and strap hinges.

HITCH: A combination of turns for securing a rope to a spar, stay or pipe.

HOUSE: See AUDITORIUM.

HOUSE LIGHTS: See AUDITORIUM LIGHTING.

HOUSING: The outside supporting structure and/or case of an lighting instrument.

HUE: The property of light which distinguishes it from gray or other colors of the same brilliance. The color itself.Physically a matter of wave length.

I

ILLUMINATION: The density of the luminous flux on a surface, measured in foot candles.

IMAGE: The picture, pattern or design thrown on a surface by a projection device.

INCANDESCENT: Emitting light as a product of heat.

INSTRUMENT: A synonym for a lighting unit.

INSULATOR: A material which is a poor conductor of electricity.

INTENSITY: 1) The power of a light source. 2) A color characteristic determined by the amount of its complement mixedwith it.

INTERLOCK: 1) To mechanically lock dimmers together so that they will operate in unison. 2) Devices or switches usedto prevent improper or unsafe operation or access to equipment and/or electrical panels.

IRIS: A device consisting of a number of thin metal plates operating to vary the size of the light beam in a circular form,either built into or attached to the front of a spotlight.

10

J

JACK: A triangular brace fastened or hinged to a piece of scenery for support.

JIR or WHIP LINE: The single load line.

JIG SAW: A power saw with a thin narrow blade, used for fine scroll work, much like a coping saw.

JOG: A plain narrow flat, usually any flat less than 3’ wide.

JUMPER: A short length of electrical cable with connectors.

JUTE: A coarse fabric made from a slender shrubby Asiatic plant. Used for scenic and drapery webbing.

K

KEEPER HOOK: An S-shaped flat strip of iron used to keep a stiffener in place on the back of a book flat.

KEY LIGHT: The main or apparent source of illumination.

KEYSTONE: A piece of l/4” plywood cut in the shape of an elongated keystone used to make and reinforce scenery joints.

KILOWATT: A unit of power equal to 1000 watts. Abbreviated KW.

KLIEGLIGHT: 1) A trade name for spotlights manufactured by Kliegl Brothers. 2) Sometimes a synonym for a bright light.

L

LACED BLOCKS: Passing cable through a set of blocks by starting from an outside sheave and following in rotation. Willusually tilt travel block when running empty.

LANG LAY: A rope in which the lay of the wires or fibers in the strand is in the same direction as the lay of the strand inthe rope.

LAMBERT: Measure of luminous flux. One Lambert equals one lumen per square centimeter.

LAMP: The complete assembly, including base, bulb, filament, etc.

LAMP DIP: A transparent or frosted lacquer used to color lamps. Not in frequent use currently.

LAMPHOLDER: The device by which a lamp is secured in a lighting instrument and to which the leads are attached; asocket.I

LAP JOINT: One piece of lumber is laid over another and nailed or screwed together.

LASH CLEAT: A small flat piece of stage hardware screwed to the stile of a flat and around which the lash line is hookedwhen flats are lashed together.

LASH LINE: Rope used to lash flats together, usually No. 8 sash cord.

LASH LINE EYE: A small piece of stage hardware, with an eye in it, attached to flat and used to attach the lash line to theflat.

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LASHING A FLAT: A means of temporarily fastening flats together by looping a rope (lash line) back and forth betweentwo flats, hooking it over a row of cleats on both of them, similar to a lacing process.

LCL: See LIGHT CENTER LENGTH.

LEFT LAY: The direction of strand or wire helix corresponding to that of a left hand screw thread.

LENS: A piece of transparent material (usually glass), frequently having one or two spherical or cylindrical surfaces, usedsingly or in combination to focus light beams.

LEKO: Trade name for an ellipsoidal reflector spotlight.

LIFI? JACK: A device for moving scenery. A lever lifts the weight of the scenery onto castors so it can ‘be rolled.

LIGHT BRIDGE: A moveable steel structure suspended over the stage or audience area usually used for suspending lightinginstruments.

LIGHT CENTER LENGTH or LCL: The distance from the center of a lamp filament to an arbitrary point on the lamp base.

LINE: A general term for a rope or steel cable used on stage. Lines are described by function, such as tie line, lash line,etc.

LINNEBACH PROJECTOR: A sheet metal hood painted black inside and using a concentrated source of light to project animage from a cut-out or painted slide. Named for Adolph Linnebach.

LIVE: Carrying current.

LIVE END: The end of a rope with which you are working.

LIVE FRONT: Having exposed current-carrying parts.

LOAD IN: The process of moving a show into a theatre putting up the set, setting the lighting, etc. Also called MOVE INor PUT IN.

LOAD OUT: Refers to taking down (STRIKE) and loading a show into the trucks at the end of the run. Also called MOVEOUT or TAKE OUT.

LOADING GALLERY: A platform attached to the side walls of the stage house used for the loading or unloading of thecounterweight arbors or carriages. Also called LOADING PLATFORM or LOADING BRIDGE.

LOBSTERSCOPE: A hand or motorized device attached to the front of a lighting instrument used to give a flickering effect.

LOCK RAIL: A metal framework attached at one side of the stage on which the rope locks of the counterweight system areattached.

LOFT: The space between the grid and the roof of the stage. Commonly called the flies. See FLY LOFT.

LOJ!T BLOCK: The pulleys or sheaves directly above the batten used to change the direction of the working line-s fromhorizontal to vertical.

LONG SPLICE: A splice used to join two ends of rope together which must run through a pulley. Should only be used withtwo ropes of the same size. Also see SHORT SPLICE.

LOOSE PIN HINGE: See BACKFLAP.

LOW TRIM: The lowest point to which a piece of scenery is flown.

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LUFF: Using two or more sets of falls, by attaching to the lead line of the first set of falls another set, to give greater Pullingp o w e r .

LUMEN: The unit of luminous flux.

LUX: One Lux is the amount of light on one square meter from a source of one candela one meter away. Also known as onemeter-candle.

M

MAGNETIC AMPLIFIER: A device using saturable reactors to modulate the flow of altematingcurrent~electric power toa load in response to a low level direct current control signal. Has been used a dimmer. Abbreviated MAGAMP.

MALLET: A hammer with a rubber or wooden head.

MASONTTE: Trade name for a form of compressed paper pulp sheet, impregnated with resin and formed under high pressure.The result is very smooth on one side and fabric textured on the other.

MARRY: 1) To attach two pipes and/or arbors together so they work as a unit. 2) Binding two lines together temporarily,either end to end or side to side.

MASTER CARRIER: See CARRIER.

MASK: To conceal the lighting instruments and stage equipment from the view of the audience, usually by the use of scenery.

MASKING FLAT or MASKING PIECE: Flat or other scenery used to cut off from view of the audience any part of thestage which should not be seen.

MAT or MATTE: Any device placed in front of a lighting instrument to shape the beam.

MAXIMUM OVERALL LENGTH or MOL: The dimension of a lamp from base to tip of envelope. In double ended lampsit is measured from base to base.

METAL HALIDE LAMP: A discharge lamp in which metal halide salts are added to the discharge lamp contents which alsocontains high pressure mercury vapor; the added metal generates additional wavelengths resulting in substantially whitelight. Frequently used in followspots.

MIRROR BALL: A sphere with small mirrors attached to its surface. When a light is focused on it images are thrown overthe stage and audience. It is frequently rotated causing the images to move.

MITER BOX: A device for cutting accurate angles with a hand saw.

MOL: See MAXIMUM OVERALL LENGTH.

MONKEY TALL: Anything used, such as a four by four [lumber), to prevent a travel block from twisting. Also to preventa turnbuckle from twisting while tightening, and after it has been tightened.

MOTORIZED RIGGING or SET: A system of electric or hydraulic motors used to raise and lower battens or counterweight’arbors or carriages.

MOUSING: Wiring the throat of a hook to prevent a choker from jumping out of the hook, also to prevent a block that ishooked to lashing or a choker, from slipping off. Also the interweaving of wires in the barrel of a turnbuckle to preventthe end bolts from unscrewing.

MOVE IN: See LOAD IN.

13

MOVEOUT:See LOADOUT.

MULJNG: Changing the direction of a rope or cable by use of a specially mounted horizontal block.

MUSLIN: A plain-woven bleached or unbleached white cotton fabric.

MYLAR: A thin, clear flexible plastic.

N

NAIL: A slender usually pointed headed fastener designed to be pounded in.

NJZUTRAL: The common current carrying conductor connected to the neutral point in electrical systems, transformers, orrotating machines and is usually connected to ground, but is not to be confused with the ground conductor.

NKOPRESS SLEEVES: Trade name for a compression type device for joining, splicing or terminating wire rope.

NONDIM: A stage circuit supplying electrical power through the use of a switch or contactor rather than a dimmer. See alsoCONSTANT.

0

OBJECTIVE LENS: 1) A lens or system of lenses which forms the image of an object. 2) Last lens in a lens system. Theone closest to the object.

OHM: Unit of measure of electrical resistance.

OLEO: See ROLL CURTAIN.

OLIVETTE: An obsolete box floodlight which could be mounted on a stand or hung.

ORCHESTRA LIFlY: An elevator in the orchestra pit used to raise and lower the floor of the pit.

OFlXAL AXIS: An imaginary line drawn through the centers of the reflector, filament and lens.

ORCHESTRA: 1) Entire main floor seating area of the auditorium. 2) Circular area in Greek theatre in which the chorusperformed. 3) A group of musicians including strings organized to perform ensemble music.

ORCHESTRA PIT: Sunken area immediately in front of the stage, intended to accommodate an orchestra.

P

PAINT FRAME: A large wooden frame to which scenery is temporarily attached to hold it in a vertical position while it isbeing painted. It is sometimes moveable to allow painting from one level.

PARABOLIC REFLECTOR: A concave reflector whose surface is in the form of a paraboloid. When a light source isplaced at the focus, the reflected light rays tend to go out in parallel rays. Used in striplights and floodlights.

PARALLEL: A collapsible frame support for a stage platform with a removable top.

PAR LAMP or PAR: Short for Parabolic Reflector lamp. A Type of SEALED-BEAM LAMP using a parabolic reflector.

PAR LIGHT: Lighting instrument using a parabolic reflector (PAR) lamp as the light source.

14

PEG: See STAGE SCREW.

PENNY (a): An indicator of the size of common nails, i.e. 4d, 6d, etc. The lower tbe number, tbe smaller tbe nail.

PHANTOM LOAD: See GHOST LOAD.

PIANO WIRE: A very thin, strong wire of tempered steel, used for flying scenery where tbe wire may be visible to tbeaudience.

PICTURE HOOK: A two piece item of stage hardware, composed of a flat strip of iron, with a book bent into one end, andanother piece bent with a receptacle to bold the book. It is used to bang pictures, shelves, etc. to flats. The book isattached to tbe picture and the receptacle to the flat.

PIN CONNECTOR: A connector made for stage lighting, the male connector having three split brass prongs which fit intocorresponding recesses in the female.

PIN HINGE: See BACKFLAP.

PIN RAIL: A part of a hemp system consisting of a metal pipe or wooden rail attached to the fly gallery and fitted withremovable steel or wooden pins used in the tying off of the working lines.

PIN SPOT: An extremely narrow beam of light or a lighting instrument designed to produce such a beam.

PIN WIRE: Iron wire, usually 13 gauge, used for pins in loose pin backflaps, usually cut to 6 inch lengths.

PIT: A recessed area in front of the stage used principally by musicians. Can also be covered and used as an extendedforestage or apron.

PITCH or LENGTH OF LAY: The distance parallel to the axis of the rope (or strand), in which a strand (or wire) makesone complete helical revolution about the core (or center).

PLANO-CONVEX LENS: A lens with one flat and one spherical surface.

PLASTICITY: The quality of revealing three-dimensionality or depth by use in variations in intensity, hue and cbroma oflight.

PLIERS: Pincers used for gripping small objects and for bending and cutting wire.

PLYWOOD: Veneer board made of three or more plies with grain laid at right angles and glued together, usually made froma soft wood.

POLYETHYLENE: A thin flexible plastic made by polymerization of ethylene.

POLWINYL CHLORIDE: Polymer of vinyl chloride. Shortened to VINYL.

PRACTICAL: Capable of being used by the actor to accomplish its apparent purpose.

PREFOCUS BASE: A lamp base of a cylindrical shape and with an interrupted flange which is inserted and secured by a 90degree turn to the right.

PREFORMED: Rope wires and/or strands that are shaped to the helical form they will assume in tbe strand and/or rope.

PRIMARY COLORS: 1) In light the hues from which all other colors may be derived by mixing - red, blue and green. 2)ln pigment they are derived by subtractive method - yellow, magenta and cyan(greenisb-blue).

15

PROPS: Short for properties. Almost anything used by the performers not scenery, usually includes furniture and decorativeitems.

PROSCENIUM: The wall between the stage and the audience containing the proscenium arch.

PULLEY: See SHEAVE.

PURCHASE LINE: Operating line in a counterweight flying system. .

PUT IN: See LOAD IN.

Q

QUARTZ-HALOGEN LAl’vlF’: See TUNGSTEN-HALOGEN LAMP.

R

RABBET: A slot or groove cut in the face or edge of a piece of lumber to receive the edge of another.

RACK and PINION: The RACK (a bar with teeth) which engages the PINION (a gear with teeth). A mechanical methodof changing circular motion into lateral movement.

RAIL: The horizontal end pieces of the frame of a flat.

RATCHET SCREWDRIVER (YANKEE): A spiral screwdriver, in which the bit is rotated by a ratchet and screwmechanism, rather than by manual turning. This operates more quickly.

RAKED: Refers to scenery angled to downstage.

REAMER: A tapered bit used to enlarge or taper holes.

REEVE: To pass the rope or cable over the sheave in a block or pulley.

REEVED BLOCKS: Passing cable (or rope) through a set of blocks, as opposed to laced blocks and in such a manner, sothat there are no lines crossed or rubbing each other.

REFLECTANCE: The reflected light divided by the incident light, usually expressed as a percentage.

REFLECTOR: Any surface which reflects light, but this usually refers to the part of a lighting instrument which collects thelight.

REFRACTION: The bending of light rays when passing from one medium to another.

REGULAR LAY: A rope in which the lay of the wires in the strand is opposite to the direction of the lay of the strand inthe rope.

RESIN: A class of solid and semisolid organic products of natural or synthetic origin with no definite melting point, generallyof high molecular weight, most resins are polymers.

RESISTANCE: A measure of opposition to current flow. Measured in ohms.

RESISTANCE DIiVhIRIER: Obsolete type of dimmer using a rheostat to control the voltage to the lamps.

RETURN: Part of the scenery which returns the downstage edge of the setting off stage to the right or left.

16

REVEAL: See THICKNESS.

REVERSE LAY: A rope strand in which the direction of lay is reversed at intervals along its length.

RHEOSTAT: A variable resistance. Sometimes a synonym for a resistance dimmer.

RIBBON: Refers to the steel channel or “ribbons” which, other than well “I” beams, make-up the grid structure.

RIGGING: The general term for the rope, wire, pulleys, blocks, etc. installed in the grid and used for flying scenery.

RXP SAW: A hand saw with coarse teeth set at the proper angle for ripping with the grain of lumber.

RIGHT LAY: The direction of rope strand or wire helix corresponding to that of a right hand screw thread.

RIVET: A metal pin with a head on one end used to fasten things together by passing the rivet through a hole and hammeringthe end opposite the head flat.

ROCKER BEAM: Beam used for hoisting flimsy trusses or long flimsy loads, also used to equalize the weight, and keep theload from buckling, such as a tank plate.

ROPE LOCK: A lever housed in a metal frame which activates a paw used to apply a gripping pressure on the operating lineof a counterweight system.

ROLL CURTAIN or DROP: Permanently tied to top batten and fastened to round tube at the bottom. Ropes are woundaround each end of the tube and reeved through pulleys overhead to provide the mechanism for rolling the curtain up ordown. Also called an OLEO at one time.

ROSIN: Residue from distilled turpentine. Rosin is used on the soles of shoes to prevent slippage. Is usually dispensed froma low, flat open box (large enough to stand in) containing powdered rosin.

ROUNDEL or RONDEL: A color media made of a circular piece of glass. Commonly used in border and striplights.

RUN A FLAT: To move a flat from one place to another.

S

SABER SAW: A power saw with a thin narrow blade, used for fine scroll work, much like a coping saw. Sometimes calleda JIG SAW.

SADDLE IRON: A narrow strip of iron, with two uprights, place across the bottom of a door flat to keep the legs fromwobbling. The flat part is attached to the bottom of the flat and the upright portions are attached to the ‘stiles of the doorframe. Also called a SILL IRON.

I

SAFETY FACTOR or DESIGN FACTOR: Is the ratio of breaking strength to the safe working load. The safety factor isdetermined by information on manufactures specifications and user evaluation of the loading situation.

SAFE WORKING LOAD: The maximum load that can be safely supported by a component.

SANDBAGS: Canvas bags, filled with sand and used as weights. They may also be used to weight down jacks or ascounterweights.

SATURATION: That property of any color possessing hue which determines its degree of difference from gray of the samebrilliance. A measure of hue.

SATURATED COLOR: Undiluted hue or pure color.

17

SAWS: Tools with thin metal blades which are toothed for cutting. The most commonly used hand saws for stage use arebacksaws, coping saws, hacksaws, rip saws and crosscut saws. Circular saws, band saws and jigsaws are commonly usedpower types.

SCARF JOINT: A lengthwise joint. Long wedges are removed from the faces of both pieces of lumber, one piece is placedupon the other and glued, screwed or nailed together.

SCENE DOCK: A frame and area used for storing two-dimensional scenery,

SCIOPTICON: A spotlight which has been modified to project moving effects.

SCOOP: A directional floodlight with an ellipsoidal or parabolic reflector which also is the housing.

SCR: See SILICON CONTROLLED RECTIFIER.

SCREW BASE: A lamp base having a spiral thread forming a screw, inserted by turning to the right. Made in several sizes.

SCREWDRIVERS: Tools for setting screws.

SCREWS: Fasteners with spiral threads used for temporary or permanent installation. Most common type for stage carpentryare wood screws, with flat heads.

SCREW: See SHARKSTOOTH SCRIM.

SEALED-BEAM LAMP: A glass lamp incorporating a reflector, filament and refracting surface in one envelope; PAR andR lamps.

SEALE: A wire rope strand construction having one size cover wires with the same number of one size wires in the innerlayer and each layer having the same length and direction of lay.

SECONDARY COLORS: Colors created by mixing equal amounts of two of the primary colors. These colors in light areamber, magenta and blue-green(cyan). In pigment the secondary colors are orange, green and violet@urple).

SEIZE: To bind securely the end of wire rope.

SELECTIVE TRANSMISSION: The process of changing the color of light by absorbing some of its component parts.Sometimes referred to as the SUBTRACTIVE PROCESS.

SET: A unit of rigging consisting of the batten and all other support cables, sheaves, and mountings. Also the complete setof flats or scenery for one scene or show.

SHACKLE: An open or closed link of various shapes, usually U-shaped, with extended legs; each leg has a transverse holeto accommodate a pin or bolt.

SHADE: 1) Any of various darker colors. 2) A color less brilliant than medium gray.

SHARKSTOOTH SCRTM: A netting with rectangular weave, stronger and has greater opacity than bobbinet. Frequentlyshortened to SCRIM.

SHEAVE: A grooved wheel in a block or pulley.

S-HOOKS: Small S-shaped pieces of wire used to attach curtains or drapery to carriers or trim chains. See KEEPERHOOKS.

SHORT SPLICE: The strongest splice used to join two ends of rope together. It cannot be used on a rope which is to runthrough a properly sized pulley. Also see LONG SPLICE.

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SHUTTER: A device for shaping the light beam consisting of either one or two pairs of thin sliding sheets, either built intoor mounted on the front of a spotlight.

SIGHTLINE: An imaginary line extending from the most extreme side or vertical seat in the house past the proscenium archto any position on stage to determine how much of the stage will be visible from that point.

SILICON CONTROLLED RECTIFIER: A semiconductor rectifier that can be controlled. Switches from open toconducting states rapidly when appropriate gate control signal is applied: Used in dimmer circuits.

SILL IRON: See SADDLE IRON.

SINGLE PHASE CIRCUIT: An electric supply using 2 hot lines and one common or neutral, wire. The potential betweenhot lines is 220 VAC and 120 VAC between any hot line and neutral. The phase difference is either none or 180 degrees.

SIZE WATER: A thin solution of glue which is mixed with pigment powders to make paint for scenery.

SLIP STAGE: A large rolling platform or wagon capable of holding a full set and all properties.

SNAP HOOK: A metal hook with a spring trigger which closes its throat.

SNAP LINE: A thin piece of line rubbed with chalk, pulled tight between two points and “snapped”, causing a straight chalkline to be marked between the two points.

SNATCH BLOCK: Pulley or block with removable side to permit its insertion or removal without having to rereeve all theline.

SNATCH LINE: Length of rope, wire or chain used in attaching to a batten.

SNEAK: To dim a light up or down so slowly so as to be imperceptible.

SNUB: To check a line, generally with a round turn, on a pin or post.

SOCKET: See LAMPHOLDER.

SOFT LIGHT: Diffuse lighting characterized by diffuse poorly defined shadows.

SOFTENERS: Anything used to protect the load or cable, also rope, from damage while making a lift, also prevents loadfrom slipping.

SPECIFlC JLLUMlNATION: A highly directional light which tends to give shadows and denote the direction and shape ofthe light, light focused on a particular area of the stage or piece of scenery. The opposite of general illumination.

SPECULAR REFLECTION: Reflection from a polished surface, equivalent to reflection from a point.I

SPHERICAL REFLECTOR: A concave reflector which has the property of sending light back to the center of curvaturewhen light is placed at this center.

SPIKE (SPIKE MARK): To mark the location where a particular piece of scenery or prop will be set oa the stage floor.Frequently done with fluorescent paint or colored tape.

SPILL LIGHT: Light from a beam that is misplaced on scenery.

SPLICE: To joint the ends of rope together, or the end of a rope to its standing part, as in forming an eye, by intenveavingthe strands of the rope into themselves. Splices are known as short, long, chain, etc.

SPHERICAL ABERRATION: Failure of a lens or reflector to focus all light from a given source to a given point.

19

SPOT BLOCK: Special placement of a loft block on the gridiron for an additional, single or special running line.

SPOTLIGHT: A lighting instrument used for specific illumination.

SPOT LINE: A single line rigged from the grid used to handle a piece of scenery which cannot be handled by the regularline sets. See SPOT BLOCK.

SPREADERS: A set of chokers or slings, of equal length used to lift a load. Also see STRETCHERS.

SPREADER PLATES: Moveable steel plates on a counterweight arbor or carriage used to keep the arbor rods from spreadingand the counterweights from falling out in case of a sudden stop.

SQUARE: A tool with a calibrated blade at right angles to the handle for marking angles accurately. See TRY SQUARE.

STACK: A pack of scenery or flats. Flats to be used are called a live stack; flats already used, as in a multi-set play, arecalled a dead stack.

STAGE LEFT and STAGE RIGHT: To the left and right respectively of an actor facing the audience.

STAGE HOUSE: That portion of a theatre building containing the stage area, fly loft, grid, and galleries.

STAGE BRACE: An adjustable hardwood pole with a hook on one end and a foot iron on the other, used to brace a flat.

STAGE SCREW: A large metal screw with a butterfly shaped handle used to fasten stage braces, jacks, foot irons, etc. tothe stage floor.

STANDING PART: Is the inactive part of the rope while making a knot.

STAPLES: Double pointed tacks, usually applied by the use of a driving device called a STAPLE GUN. Can be eithermanual or air operated.

STEP LENS, STEPPED LENS: A concave-convex lens resembling a Fresnel lens, but with the sharp edged characteristicsof the piano-convex lens.

STEREOPTICON: A lensed projection instrument for projecting an image from a slide.

STIFFENER: Usually a 1” X 3” wooden batten used to increase the rigidity of scenery. On hinged flats, it is attached acrossthe joint to the toggle rails by means of keeper hooks.

STILE: The vertical side pieces of the frame of a flat.

STRAND: A plurality of round or shaped wires helically laid about an axis in one or more layers.

STRETCHERS: The temporary members placed in flats and ceilings, used to make them free of wrinkles, also lengths oflumber used to connect the discs in columns and trees.

STRIPLIGHT: A lighting instrument containing a number of lamps arranged in a line, used for general illumination. Usuallyshortened to STRIP.

STOP BLOCK: 1) A short length of lumber used to prevent one flat from slipping past another when making an inside lash.2) A piece of lumber to prevent an arbor or counterweight carriage from moving past a point on the track.

STOP CLEAT: A flat cleat; used to stabilize a flat which is lashed to another flat at right angles to form a comer. It isattached to one flat, and projects out to brace the narrow edge of the flat lashed at right angles.

20

STRAP HINGE: A hinge with very long flaps, compared to its height, which is used for hinging heavy or large pieces ofscenery.

STRIKE A SET: To remove all scenery and props from the stage. Shortened to STRIKE

STYROFOAM: A white, porous, lightweight plastic made from polystyrene beads molded under heat and pressure into sheets.

SUBTRACTIVE PROCESS: See SELECTIVE TRANSMISSION.

SUNDAY: Knot used to hold several lines together or tie off an arbor or counterweight carriage operating line.

SWEEPS: Curved or structural members of an archway flat which give it its distinctive shape.

T

TAB or TAB CURTAIN: 1) A curtain rigged to open diagonally, presenting a draped effect. 2) A piece of fabric or a flatused chiefly to mask off stage spaces.

TACK HAMMER: A small hammer, one end frequently magnetized, used on small sharp nails with broad heads commonlyused to hold upholstery fabric and at one time also used on carpet.

T-BAR or T-BAR TRACK: Vertical metal tracks mounted against the side wall of the stage to prevent side movement of thecounterweight carriage or arbor in a counterweight flying system.

TAG-LINE: A length of rope used to guide a load, being lifted, into a desired position. See BREAST LINE.

TAKE OUT: See LOAD OUT.

TEASER: A horizontal border curtain just upstage of the main curtain.

TEMPLATE: 1) A special work bench used in the construction of flats. 2) A metal plate with a shaped opening in it, placedinside a spotlight to shape the beam. Also see GOBO.

TENSILE STRENGTH: The maximum stress a material subjected to a stretching load can withstand without tearing.

TENSION BLOCK or PULLEY: A block or pulley mounted below the lock rail on a T-bar or wireguide counterweightsystem around which the operating line passes.

THICKNESS: A piece of lumber or other material attached to a flat or opening in a flat to give the effect of depth orthickness. Also called a REVEAL.

THIMBLE: Grooved metal fitting to protect the eye of a wire rope.

THREE-FOLD: Three flats hinged together to fold inward, face to face.

THREE PHASE CIRCUIT: A electric power supply circuit using three hot lines and one common, or neutral, wire. Thepotential between any hot line and neutral is 120 VAC and between any two hot lines is 208 VAC and the circuits differin phase by 120 degrees.

THRUST STAGE: An extension of the stage floor into the auditorium allowing the audience to be seated on three sides.

THYRATRON: A hot-cathode gas tube in which one or more control electrodes initiate but do not limit anode current exceptunder certain operating conditions. Used in dimmers at one time.

21

-

THYRISTOR: A transistor having thyratronlike characteristics; as collector current is increased to a critical value, the alpha(gain) of the device rises above unity to give high-speed triggering action. Used in dimmer circuits.

TIE LINE: Small line, usually sash cord, used to fasten drops or other drapery to battens.

TIN SNIPS: Large, heavy shears used for cutting tin or light metal.

TINT: 1) Any of various lighter colors. 2) A variation of a color produced by adding white to it and characterized by relativehigh brightness and low saturation.

TIP JACK: A device used for moving heavy or awkward pieces of scenery. Similar to a rigid jack but is mounted on casterswith the vertical member at less than a 90 degree angle to its base. Set piece is tipped back on to the casters to be moved.

TOGGLE RAIL (TOGGLE): The horizontal cross member of the wooden frame of a flat, placed parallel to the end rails,somewhere behveen them in the interior of the frame. It is attached to the stiles.

TONE: Color quality or value.

TOP HAT: A short metal cylinder installed in front of a spot light to reduce beam spread and/or spill.

TORMENTOR: Vertical masking pieces placed just up stage and on either side of the proscenium.

TORMENTOR BATTEN or PIPE: A vertical pipe located just upstage of the tormentor.

TOWER: A tall light stand, or ladderlike structure, usually moveable, for mounting lighting instruments.

TRANSFORMER: A core of iron, usually laminated, on which two coils of wire are wound. The primary coil, carryingan alternating current, induces an alternating current in the secondary. Induced secondary voltage is determined by ratioof primary coil windings to secondary coil windings.

TRAP(S): A removable section of the stage floor, which allows for access to the area under the stage floor.

TRAVELER: A slotted steel or wooden track, used to hang draw curtains.

TRANSMISSION FACTOR: Percentage of light passing through a material.

TREE: Light stand with horizontal arms.

TRIAC: General Electric trade name for a gate controlled device much like an SCR, but requiring only one for full wavecontrol.

TRIM: 1) To set the height of a piece of scenery for use during the performance. 2) To adjust a scenic unit to hang level.3) To change carbons in an arc followspot. 4) Refers to hanging properties on the walls of a set or placing them on thefurniture. Includes Draperies, pictures, sconces, ashtrays, lamps, vases, etc.

TRIM CHAIN: A length of chain with a snap hook on one end and a large ring on the other. The batten is place throughthe ring and various pieces of scenery attached to the snap hook.

TRIM CLAMP: A piece of stage hardware used with hemp flying systems consisting of a metal box held together by threebolts and equipped with a ring to which sandbags or counterweight carriages can be attached. The ropes of a line set gothrough the box and can be tightened and held fast after being trimmed.

TRIP: To raise the bottom of a piece of flown scenery with lines attached to the bottom in such a way so that it occupies avertical height approximately half its height.

TRY SQUARE: A small square used for marking right angles.

22

TRUSS: A framework made with triangular bracing to make a rigid structure.

TUMBLER: A vertical length of 1’ X 3” lumber hinged behveen two flats of a three fold which will permit three flats of thesame width to fold into a compact unit.

- TUNGSTEN-HALOGEN LAMP: An improved form of the incandescent lamp which contains a small amount of halogengas in the bulb. Also called A QUARTZ-HALOGEN LAMP.

TURNBUCKLE: Device for making limited adjustments in length. It consiSts of a barrel and right and left-hand threadedbolts.

TURNTABLE (REVOLVING STAGE): A rotating platform or portion of the stage flpor.

TWO-BLOCKED, or BLOCK and BLOCK: When the blocks are right up to each other and can go no farther. Also usedas a term, that you are as far as you can go, with whatever you are doing.

TWOFOR: Electrical “Y” splice used to combine two loads into one circuit.

U

ULTRAVIOLET LIGHT: Invisible light of shorter wavelength than visible violet, capable of producing fluorescence incertain substances, often called blacklight.

UNDERWRITER’S KNOT: A knot tied in the conductors of a lamp cord to keep strain off the connectors.

ULTIMATE STRENGTH: See BREAKING STRENGTH.

URETHANE: Combustible, toxic, colorless powder; soluble in water and alcohol.

- URETHANE FOAM: A lightweight, closed cell plastic foam made from URETHANE.

V

VALENCE: A horizontal masking border just downstage of the main or act curtain and usually made of the same material.

VALUE: A pigment color term referring to the light or dark (tint or shade) quality which is determined by the amount of blackor white pigment added.

VELOUR: Any of several heavy deep pile fabrics, frequently used for main curtains.

VENEER: A thin layer of costly wood glued over a thicker layer of less expensive lumber, usually for decorative purposes.

VINYL: See POLYVINYL CHLORIDE.

VISE: A tool with one fixed and one movable or two moveable jaws used to hold an object to be worked on.

VOLT: A unit measure of electromotive force or difference of electrical potential. One volt will cause one ampere of currentto flow through one ohm of resistance. Often referred to as voltage.

23

W

WAGON: A rolling platform, usually on casters or wheels, used for rapid scenery changes.

WARRINGTON: A wire rope strand construction in which one layer of wires, usually the outer, is composed of alternatinglarge and small wires.

WALK IT UP: A method of raising a large or heavy flat. Done in teams of.four or more, two persons stand and brace thebottom of the flat. The other two start at the top of the flat and lift from the top rail. They walk forward, towards thebottom of the flat raising the flat by hand over hand down the stiles, until the flat is vertical.

WASH: General Illumination covering the entire performing area. Usually of a single color.

WATT: A measure of electrical power. Can be calculated as the product of the voltage and current.

WEBBING: Strips of fabric, usually jute, used to reinforce the tops of curtains, drops and stage draperies.

WELL: The space between the beams on the grid over or on which the loft blocks are placed and which allow the workinglines to drop to the batten.

WEST COASTING: Lowering drapery or drops directly into storage bags or containers without folding.

WHIP: To bind the ends of fiber rope to prevent fraying.

WINCH: A manual or power operated device used to wind cable on to raise and lower stage equipment.

WING NUT: A threaded nut with extensions on each side which make it possible to tighten or loosen by hand.

WIRE GUIDE SYSTEM: Refers to the use of steel cables to prevent the side movement of the counterweight carriage orarbor in a counterweight flying system.

WORKING PIECE or PIPE: A flown scenic piece or batten which moves during a performance.

WORKLIGHT: Light used for set-up, rehearsals or scene shifting.

WRENCHES: Tools used for loosening or tightening nuts, blots, pipe, etc., composed of a hand with jaws, at one or bothends, which may be fixed or adjustable. See CRESCENT WRENCH.

X

X-ACT0 KNIFE: A trade name for a small, very sharp knife with interchangeable blades. Used for carving, trimmingmuslin, cutting stencils, etc.

XENON ARC LAMP: An arc lamp filled with Xenon gas giving off light with an intensity approaching that of the carbonarc. Requires extensive safety measures when handling.

X-RAY: See BORDERLIGHT

Y

YANKEE SCREWDRIVER: Trade name for a RATCHET SCREWDRIVER.

YOKE: The U-shaped part of a spotlight to which the C-clamp is attached which permits the light to be moved in the verticalplane.

24

Z

ZIP CORD: Number 18 or 16 gauge SPT type electric wire. Not suitable for stage work

ZIP SCREW: Popular name for drywall screws.