Theatre Design & Technology - Fall 1985 - 8

filament in 1963. It was a more efficient source and operated
at 3200 degrees Kelvin, producing a spectral output with twice
the blue energy of the old 2900 incandescent lamps. For cyc
lighting, this additional blue was most welcome. By the midsixties the source was termed tungsten halogen and a range of
wattages was available with an anticipated life of 2000 hours.
The new lamps brought about changes in luminaires. The
early applications of the lamp were in fixtures designed for
traditional incandescent lamps. The light center length was
the same and it wasn't necessary to alter the reflector design.
However, the tungsten halogen lamp operated at a higher
temperature and the fixture housing didn't adequately dissipate the heat. Furthermore, since the lamps were physically
smaller, it was possible to replace a 500 watt T-12 or T-20 with
a 750 or 1000. Asbestos gloves were required for handling.

When the two-pin-base lamp was introduced, the major
manufacturers designed fixtures to dissipate the heat. New
housings, reflectors and lenses assured maximum output and
operation for the full rated life. In recent years the old "base
up" position moved to axial mounting in ellipsoidals. Some
of the manufacturers moved to die casting during this period
to facilitate production of luminaires.
6

Theatre Design & Technology / US ITT / Fall 1985

Ariel Davis had pioneered the use of extruded aluminum
in housings in the late fifties. He utilized the PAR lamps with
integrated reflectors as his light source. It was not until many
years later that PAR and R lamps were utilized in borders and
strips for cyc lighting. The touring groups later adopted the
durable PAR lamps as their standard source for the concert
circuit.
The CSI, HMI, Xenon, and Mark 350 virtually replaced
the carbon arc in follow spots. They didn't require the expensive exhaust systems.
In 1960, the choices in color media were Roscogel and
Brigham gelatines and Cinemoid and Roscolene acetates. As
the use of quartz lamps expanded during the sixties, the heat
stability of these media became a greater problem. Because
the filaments were compact, reflectors and lenses tended to
reimage the filament on the gel causing rapid fading or actual
burn through. The smaller lamp size permitted the use of
higher wattages in smaller housing, compounding the heaton-the-filter problem. By the late sixties there were two
polyester-based media available, Geletran and Roscolar, and
Lee polyester appeared in the mid seventies. In 1976, Roscolux was introduced utilizing polycarbonate, an extremely durable, heat-stable base resin.
The developments in lighting control since 1960 can fairly
be termed a revolution. In that year resistance and autotransformers were the methods of dimming in widest use. Tabs
reported some salt water dimmers still operating at the Aldwych Theatre. The GE thyratron system was still operating at
Radio City Music Hall and it was an approach to electronic
dimming that was specified in many installations. The magnetic amplifier (or magamp) dimmer had been the most
modern system.
In 1958, GE had announced the silicon-controlled rectifier and by 1960 Kliegl was installing SCR systems and Century had the C-Core line. The other dimmer manufacturers
were offering alternative designs and the SCR was an instant
standard.
After a series of short-lived punched card and stapled
card developments, the computer front-end was finally married to the SCR dimmer in 1968. For the first time, the lighting control system had a true instantaneous memory. The
lighting designer or television lighting director could now reproduce in the show what he or she had perfected in rehearsal. The rapid development continued with the utilization of
more compact microprocessors and innovative software design. Size and prices were reduced and systems offering virtually unlimited control were within the budget of most
organizations.
Over the past twenty- five years we've seen progress in the
design of lamps, fixtures, filters and lighting control. The
developments in other aspects of technical theatre have been
equally significant. Rigging was based upon the counterweight and T-track systems. George Izenour installed hi~
winch grid at the Loeb Drama Center in 1960. We have
moved to today's microprocessor-controlled fully motorized
point, batten and plak systems.
Set construction was a textile and wood craft. Basically all
the plastic resins, foams, adhesives and metallized material~
have appeared in our market since 1960. Animal glue, dr)
pigment and such additives as "Elvanol" have been replaced
with a wide range of resin-based paint systems and a stablE
casein.

Table of Contents for the Digital Edition of Theatre Design & Technology - Fall 1985