Theatre Design & Technology - Feb 1971 - 31

OPE~FACED

INSTRUMENTS
(Continued from p. 24)

All instruments used 500-watt lamps. A total
of 9,000 watts of light were used on the stage at
anyone time as compared to the 11,950 watts
needed for the PAR fixtures. The decreased light
level and the greater coverage on the stage after
relighting provide an idea of the improved efficiency of the new equipment.
The color temperature of incandescent theatre
lamps used is 2900° to 3000° Kelvin when they
are receiving a full 120 volts. The color temperature of the lamps used for television is 3200°
Kelvin. There were 2900° and 3000° Kelvin
lamps available for all the fixtures used, but we
were trying to use what we had on hand.
Gelatran was used as the color media because
of its heat-resistant properties. It was developed
for television and motion pictures and its durability,
color life, and heat-resistant qualities justify its
present use in theatre.
The colors were not heavily saturated because
of the closeness of the audience. However, as a
result of the color temperature of the lamps, we
had to double all colors in order to provide the
same color that would have been provided by the
2900 0 1amps.
Heat was also a consideration. Several production personnel who were unfamiliar with the equipment expressed the fear that it would be too hot,
but temperature readings before and after the installation of the tungsten-halogen instruments
showed no heat rise.
The spun glass in the Multi-Broads worked as
planned, and the people in the first two rows
were not bothered by the lights. With a Iittle more
grid height, no spun glass would have had to be
used at all, thereby increasing the overall light
level by another 40 footcandles. In this case,
the additional light was not required, but on larger
stages, the increased distance would have required a higher initial lumen level.
The experiment was a success for two reasons.
First, we proved that the open-faced instruments
can meet some of the physical requirements of the
theatre. Second, they were shown to present no
problems to actors.
This was only an experiment and not the ultimate in lighting design, but the open-faced instruments performed as expected.
There is no question but that advanced technology is needed in lighting equ ipment. There are
many techniques, materials, and concepts being
generated in related and unrelated fields.
It is unfortunate that advantage is not taken of
these tools. 0

!'!!!! !!!.C!RIC

COMPANY INC 940
*

Indullno' O,nt flmhllfSf III 60116

Maybe this
belongs in your
reference files ...
If you desire an understanding of the dynamic

Open St.age Theatre and its particular techniques,
write for Hub Bulletin 126. It contains discussions on auditorium design, size and shape of
platforms, nature of walls, floors, ceilings, and
seating.
Its 68 pages are also crammed with specific details of scenery design techniques, background
projection and parts of the lighting and lighting
control systems required for Open Stage.
Write today, on yoW' letterhead, requesting Bulletin 126. It's yoW's without charge.
If you already are working with an Open Stage,
ask too, for Bulletin 121 "Freestanding Scenery"
by James Hull Miller.
HUB BULLETIN 126 is the seventh in a
series, covering major areas of educational
theatre and educational TV as explored by
Hub with the help of leading designers and
consultants. This continuing research is why
our engineering and design staff "knows"
the exacting requirements of theatrical
lighting and lighting control systems.

HUB
ELECTRIC COMPANY, INC.
940 INDUSTRIAL DRIVE
ELMHURST, ILL. 60126

RESIDENT ENGINEERS IN PRINCIPAL CITIES

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