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to the near black leg remains in as much light as pos-
sible. Most units assigned to this function have beam
spreads ranging between 30 and 90°.
Combining the available instrumentation and the
needs of the production makes these kinds of gen-
eral height distinctions somewhat fuzzy. Any number
of instrument types and focuses can be specified for
each design. Most designers follow the guideline stat-
ing that instruments mounted at the top of the boom
focus to the far side, while lower-mounted instru-
ments focus to the near side. The focused beams don’t
“cross,” reducing the possibility of having too much
intensity between two overlapped light beams in the
same system.
Almost any instrument type can be used for boom
sidelight. When the light beams need to be shaped
with a sharp edge, ellipsoidal lighting instruments
are often the first choice. While other instrument
types are just as useful to produce sidelight, their
beams often require additional accessories to shape
the beams. This often translates into more time and
effort spent preparing or focusing them. In addition,
the combined weight of several accessories can alter
the boom’s center of balance, and may increase the
overall footprint of the sidelight position. If alternate
instruments are chosen for the job, then the amount
of scheduled time or space may need to be increased
in order to use them.
The successful boom sidelight system begins with
symmetry between positions. Regardless of what
instrument is used for each system, the unit type
should be the same and be mounted at the same ver-
tical height on each boom. Matching the unit type
means that kind of light will be the same throughout
the system. Matching the mounting height insures
that the focus angle will be duplicated in each open-
ing. Not only does this mean that the light source will
be consistent throughout the system; it also means the
performers will contend with the same vertical instru-
ment arrangement while running around the booms.
Next, successful boom sidelight instruments
attempt to be as compact as possible. Often this
translates into all the instruments being hung in the
same horizontal plane, one directly above, or below
the other. While some booms mount the instruments
directly upstage or downstage of the vertical support-
ing pipe, the even more compact booms reduce this
“thickness” by hanging the instruments onstage of
the vertical support. Not only does this often facilitate
focus, but it also translates into more space between
the boom and either of the masking legs for perform-
ers or other objects to pass around it. Sometimes the
instruments are double-hung, both sticking out on
either side. The phrase “double-hung” implies a pair
of instruments, both vertically mounted at the same
height. Obviously their combined width makes the
overall boom width “thicker.” In tight quarters, a typ-
ical plotting tactic is to restrict mounting double-hung
instruments to only above head height; single-hung
units are mounted from the floor to approximately
8-0, in order to provide as much passage space as
possible for performers or moving props between the
sidelight booms and masking legs.
Downlight
Downlight, or toplight, is generally defined as a
system, instrument, or light beam originating directly
above a person standing on a stage. The visual epit-
ome of downlight are shafts of light pointing straight
down, so that light covers the head and shoulders of
the person. The combined light beams form symmet-
rical pools, equidistantly overlapping left to right, and
up- and downstage. A full stage single-color down-
light wash typically covers the entire performance
area, from side to side, and from the upstage scenic
stack to head height at the downstage light line.
In reality, downlights rarely point straight down.
An overhead hanging position rarely gets placed
directly above each zone of focus points. In many
cases, the instruments end up on electrics that are
located in the up- or downstage side of an opening.
In order for the focused pools to appear properly
overlapped up- and downstage, the downlights are
slightly tipped during the focus to produce that effect.
Since this is one of the systems that is more obvious
to the audience’s angle of observation, however, care
must be taken during the plotting, the hang, and the
focus to create the illusion that the instruments are
focused “straight” down.
While the focus points for downlights in the first
zone can be centered in the middle of the opening,
they may just as easily be shifted upstage, so that
the downstage beam edges land close to the down-
stage light line. The focus points for downlights in
the final zone, on the other hand, are often shifted
downstage so that the upstage beam edges land at the
upstage light line. If the section is drawn so that accu-
rate trims and beam spreads of the instruments are
shown, it will be clearly seen where the beam edges
and focus points of intermediate zones will need to be
located, so that the pools symmetrically overlap.
The number of downlight zones, and the number
of instruments used in each zone, are unique for every
show. When a production is presented on an open
stage, however, the focus and symmetry of a downlight
system will be much more apparent to the audience’s
angle of observation. Depending on the overhead elec-
tric trim heights and the beam sizes used for the sys-
tem, the number of zones is often equal to or less than

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