LIGHTS STUDY GUIDE

What factors influence the choice of lighting fixtures for a show?

Inventory & budget, physical limitations, quality of light, intensity & color temperature, beam shaping and control, stage lighting optics.

What determines the quality of light from a fixture?

The light source itself and how the light is manipulated after it leaves the source, controlled by the optics of the fixture.

What are the three types of reflectors commonly used in stage fixtures?

Spherical, parabolic, and ellipsoidal reflectors.

What is the law of reflection?

The angle of incidence is equal to the angle of reflection.

What type of reflector is used in Fresnels and follow spots?

Spherical reflectors.

What is the focal point in relation to a reflector?

The specific point at which the light source must be placed to achieve the desired reflective pattern.

How do parabolic reflectors differ from spherical reflectors?

Parabolic reflectors reflect rays parallel to one another, producing a concentrated and harsh beam.

What are the two focal points of an ellipsoidal reflector?

The primary focal point (nearest the reflector) and the conjugate focal point (distant).

What does refraction of light refer to?

The bending of light when it passes into a denser medium.

What is a plano-convex lens?

A lens with one flat (plano) surface and one outwardly curved (convex) surface.

What is a Fresnel lens designed to do?

Save weight and lessen the chance of cracking due to heat, with steps cut into the glass.

What is the significance of the Profile Spotlight?

It is the most efficient and versatile fixture, creating a concentrated, sharp light with built-in beam-shaping capability.

What is the purpose of the C-clamp in a lighting fixture?

To attach a lighting fixture to a pipe batten.

What is the function of the gate in an ellipsoidal reflector spotlight?

It is where shutters, iris, and gobos are located, close to the reflector's secondary focal point.

What does a gobo do in lighting?

It is used to project patterns or images with light.

What is the purpose of a light plot in theatrical production?

It links the designer's ideas to the reality of production and must be accurate and complete for effective load-in.

How are fixtures numbered on a light plot?

By position, starting at house right and moving to house left.

What does the fixture key on a light plot indicate?

It shows which symbol the designer is using for a specific unit, including wattage and beam spread.

What is a boom in lighting design?

A structure consisting of a heavy metal base and a length of pipe to which lighting fixtures are attached.

What is the importance of fixture height in a light plot?

It must be indicated to ensure proper placement and effectiveness of the lighting design.

What is the purpose of the color key in a light plot?

To explain the numbering and lettering system used for each brand and type of color medium.

What does the term 'load-in' refer to in lighting design?

The process of hanging, circuiting, and focusing lights for a production.

What is the role of optics in a lighting fixture?

To manipulate the light after it leaves the source, affecting its quality and direction.

What is the main advantage of using dichroic-coated glass reflectors?

They allow infrared and ultraviolet rays to pass through, reflecting only visible light for a cooler beam.

What is a zoom profile in lighting fixtures?

A profile spotlight with movable lenses that provide an adjustable beam diameter.

What is the significance of the 'R', 'L', and 'G' series in color keys?

'R' series = Roscolux, 'L' series = LEE Filters, 'G' series = GAM Color.

What is the purpose of shutters in an ellipsoidal reflector spotlight?

To allow the beam to be shaped in a linear manner from any of four directions.

What is the function of a boom base in lighting design?

The boom base is drawn as a circle and located in its proper position on the plan.

What angle should a pipe be drawn at when coming out of a boom base?

At an angle of 45 to 60 degrees.

What is a focus chart?

A precise record of the focus information for all the fixtures in a production that allows operators to reproduce focus accurately.

What are magic sheets used for in lighting design?

Paperwork that aids a designer in setting and adjusting lighting levels, often listing groups of channels by function or color.

What are the three types of lamps currently used in theatre?

Incandescent, Arc, and Gaseous Discharge.

What is an incandescent lamp composed of?

A light source (filament), a glass envelope (bulb), and a base.

What is the main characteristic of a tungsten-halogen lamp?

It maintains initial intensity throughout its life span and is more compact than standard incandescent lamps.

What is the purpose of the gas in the bulbs of incandescent lamps?

It prevents the filament from oxidizing.

What does the ANSI lamp code represent?

A system for identifying lamps using a different three-letter code for each lamp.

What is DMX?

DMX (Digital Multiplex) is a protocol used to control devices such as lights or fog machines.

What does DMX-512 refer to?

A standard communication protocol for lighting-control systems consisting of 512 discreet control channels.

What is the role of Ethernet in lighting control?

It allows for the distribution of multiple DMX signals and connects different systems together.

What is soft patching in lighting design?

The electronic patch system that makes logical dimmer/circuit-to-channel assignments easier.

What should be considered when determining lighting areas?

Shape and size of the setting, degree of control desired, blocking of actors, and equipment inventory.

What is the diameter of the beam from a lighting fixture dependent on?

Throw distance and the fixture's beam spread.

What is the significance of the Kelvin scale in lighting?

It is used to identify the color temperature of a light source.

What is the main advantage of using tungsten-halogen lamps over standard incandescent lamps?

They are more compact and maintain intensity throughout their lifespan.

What does the term 'filament' refer to in lighting?

A thin piece of tungsten that glows and emits light from within a lamp.

How are the shapes of bulbs designated?

By a letter or letters.

What is the purpose of the base in a lamp?

It fits into a socket, holds the lamp in position, and provides electrical contact.

What is the function of the crosshatched lighting fixture in a plot?

It indicates that another view of the fixture appears elsewhere in the plot.

What is indicated by heavyweight Roman numerals or letters on a light plot?

They mark the center of the focus area.

What is the primary objective in designing a magic sheet?

To keep it clear and concise, ideally on one page.

What happens if the system's patch is left unassigned?

Dimmer-to-channel will default to a one-to-one relationship.

What is the importance of fixture height in lighting design?

It must be indicated for accurate positioning and focus in the design.

What is the role of a lighting designer in determining lighting areas?

To consider various factors such as setting shape, control degree, actor blocking, and equipment inventory.

What does the term 'gaseous discharge' refer to?

A type of lamp where light production depends on the reaction of gases to an electric arc.