A Practical Guide to Stage Lighting, 2nd Edition

A Review

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appearance of multiple sources of light produced by a

single source. When this tactic is employed, the sym-

metric hanging locations for template systems may

be as important a choice as the kind of ellipsoidal

or the particular template used. Instruments hung on

overhead electrics, for example, are often located at

specific distances from centerline, so that their beams

will produce symmetrical shafts in the air.

Templated light often combines these applica-

tions. They may be included in a plot to light both the

stage and the performers moving through the space,

or they may be designed to project light that is both

seen in the air and striking objects on the stage.

Occasionally, templates will be used to provide

a breakup pattern over an entire backdrop. To pro-

duce this effect, initial choices are made to define the

hanging position, the beam spread, and the number

of ellipsoidals. To maintain a consistent focus for

the beam edge of each “hole” in the template, the

instruments are often placed so that the templates

focus straight into the backdrop. As a result of this

choice, the instruments are often placed either on the

first electric or the balcony rail. Drawing a section

from either position shows the actual throw distance

and the potential coverage using various-sized beam

spreads. Choosing the proper beam spread is directly

related to the number of instruments needed to cover

the entire backdrop. One formula used to determine

the total number of instruments needed is based on the

cautious assumption that a typical template will

cut the overall diameter of an instrument’s beam by

about 50%. Based on that assumption, the number

of instruments of any particular beam spread can be

determined.

When template systems are used to “break up”

an entire performance surface, they are often designed

so that they produce as much patterned light as possi-

ble, while requiring the fewest instruments to achieve

that coverage. To achieve the maximum actual throw

distance for each instrument, the units are often

plotted into side galleries, ladders, or overhead pipe

end hanging positions. The farther the actual throw

distance, the larger the eventual gobo projection.

Templated instruments are also combined with

many other devices to provide visual movement while

only using conventional ellipsoidal instruments. Gobo

rotators, film loops, and other devices expand the

ways that templates can be used to create a more

diverse visual environment.

Creating all of these systems is achieved by

understanding the different concepts and compo-

nents of theatrical light. This understanding begins

by examining the properties and control of electricity,

the form of energy that allows theatrical lighting to

exist.

ELECTRICITY AND DISTRIBUTION

Electricity is a fundamental form of energy that is

created by the movement of atomic particles called

electrons. The combination of technological devices

that manipulate electricity, coupled with the desire to

control the visual environment, has helped propel the

lighting designer’s role in theatre. From the artistic

point of view, the lighting designer visually reinforces

the director’s interpretation of the production. From

a technical point of view, the lighting designer con-

trols the amount of electricity to each lighting source.

While the lighting designer is typically not required

to have a detailed knowledge of electricity, he or she

should have a basic grasp of this form of energy.

The designer must have a comprehension of how to

control electricity, if for no other reason than safety.

Basic Electricity

A basic electrical circuit is comprised of three compo-

nents: a source of electricity, a load using the electric-

ity, and circuitry providing a path between the two.

There are two basic types of electricity: direct and

alternating current. Every electrical system uses one

of these two types. A demonstration of direct current

can be seen in a typical flashlight. The electrical flow

moves in a single direction of polarity from the posi-

tive terminal of the battery (the source), through the

bulb (the load), and back to the negative terminal of

the battery to complete the circuit. In today’s world,

low-powered direct current is seen in batteries, and is

used to internally power computer devices.

Most electrical power provided to the consumer,

ranging from entire nations to household outlets, is

alternating current. This type of electricity is created

by large generators, which essentially consist of

fixed magnets surrounding a rotating shaft carry-

ing three coils of insulated wire. The rotation of the

shaft within the magnetic field generates pulsing elec-

trical current in each of the three coils. The pulsing

current reverses direction, or alternates polarity, 60

times a second, thus the term 60-cycle alternating

current. The individual current produced by each of

the three coils is called a phase (or a “hot”). Three-

phase 60-cycle alternating current is the standard

distributed throughout the United States, but the

actual number of phases installed in any building or

performing facility may vary. Regardless of the num-

ber of phases, an additional wire is present which

completes the circuit back to the generator, called the

neutral. In many installations, another wire is also

included as a safety precaution, called a ground.

Electricity has three related electrical attributes:

amperage, wattage, and voltage, which are measured