Ch. 16 Theatre

the distance from the lens at which the light rays converge into a point; for lenses used in stage-lighting instruments the focal length is most frequently measured in even inches

a lens with one flat and outward-curving face

to soften the appearance of light by using a translucent filtering element to scatter the rays

the light-producing element of a lamp; usually made of tungsten wire

the Pyrex glass or synthetic quartz container for a lamp filament and gaseous environment; synonymous with envelope

one millionth of a watt

a device for measuring specific wavelengths of life

to put a color filter into a color frame and place it in the color-frame holder of a lighting instrument

generic term referring to flexible (gelatin or plastic) color media

a glass color medium for use with striplights; frequently has diffusing properties

an ellipsoidal reflector spotlight with movable lenses that allow the focal length to be changed

the shadow line created by the edge of the shutter when it is inserted into the beam of light emitted by an ERS

a lightweight metal holder for color media that fits in a holder at the front of a lighting instrument

a thin metal template inserted into an ellipsoidal reflector spotlight to project a shadow pattern of light

a hand-held router similar to a dentist's drill, which can be equipped with a number of bits for grinding, cutting, or carving of wood, plastic, and metal

a device with movable overlapping metal plates, used with an ellipsoidal reflector spotlight to change the size of the circular pattern of light

an accessory for a Fresnel spotlight whose movable flippers are swung into the beam to control it

an accessory for a Fresnel spotlight that masks the beam to create a circular pattern; also called a snoot or a top hat

a lever-actuated device used to control the height of the top and bottom edges of a followspot beam; also called a chopper

a mechanical dimming device used in followspots

a device that changes the voltage in an electrical system; the output voltage of a step-down transformer is less than its source; a step-up transformer increases it

refers to plays that rely on the spoken word to convey the message; does not include musicals, reviews, dance, opera, or concerts

in this context, primarily refers to touring rock and country western shows

in this context, refers to night clubs in which high-energy music (live or recorded) is the prime attraction

to rotate an object, such as an ERS, about its vertical axis

to rotate an object about its horizontal axis; to pan vertically; the instrument is suspended from a yolk, which allows the fixture to both pan and tilt

an electric motor whose movement consists of discrete, angular steps rather than continuous rotation. Precise movement is achieved by programming the motor to run, in either direction, for a specific number of steps

a metal device that absorbs heat from an operating unit and dissipates it into the air

the wires in low-voltage control systems are frequently called "lines" rather than "wires"

separate and complete; in this case, pertaining to information represented by binary code

• 1--to transmit two or more messages simultaneously on a single channel;
• 2--to carry out several functions simultaneously in an independent but related manner

the area in an auditorium that is close to the stage

a device, usually electronic, that effects a gradual changeover from one circuit to another; in lighting it gradually changes the intensity of one or more dimmer circuits; in sound, it changes audio circuits or channels

a computer/electronic term meaning a system malfunction or error

nonpermanence; in computers, a volatile memory will be lost if the computer loses its power supply

a computer storage device. A spinning magnetic or optical disk on which data are stored and from which data can be retrieved

a thin plastic disk coated with metal oxide, used to record the information stored in a computer's memory

in reference to hard drivers, to become inoperative. Data normally cannot be retrieved after this

a compact disc on which data can be recorded and read by the user

audio recorder tape, used in computer storage

audio recorder tape for use in small cassettes; used in computer storage

an electronic patching system in which one or more dimmers can be assigned to a control channel, which in turn controls the intensity level of those dimmers

the grouping of two or more dimmers/channels under one controller

a gradual increase; in lighting, usually from darkness to a predetermined level of brightness; synonymous with fade-up

a gradual decrease; in lighting, usually from a set level of brightness to darkness

a fade-in in which the fade-up and fade-out are accomplished at different rates or speeds

refers to the time interval that the second part of a split time fade follows the first

designing the light cues; manipulating, and recording, the distribution, intensity, movement, and color of the lights for each cue to create the appropriate look for that moment in the play

an electrical Y that has female receptacles at the top of the Y and a male plug at the bottom leg of the Y used to connect two instruments to the same circuit

a lighting fixture, frequently a scoop, PAR, or other wide-field-angle instrument, hung over the stage to facilitate work; generally not used to light a production

a small connecting strip, containing four to eight circuits, that can be clamped to a pipe or boom

a connecting box, usually containing three to six circuits, the top of which is mounted flush with the stage floor

a connecting box similar to a floor pocket but mounted on the wall