A Review
15
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

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