Theatre Design & Technology - Feb 1969 - 8

Program Output: Cover Flood Contol. The relays in the
"memory unit" fed three different types of output devices.
The three relays operating the three screen cover floods
were each three-pole devices. The purpose of this was to
permit additive mixture effects on each of the three screens.
The relays controlled "on" and "off" in each screen and
manually operated dimmers allowed variation in color and intensity in all three screens.
Projection Control. Inasmuch as the Carousel projectors were
rented, no internal modifications could be made. Simply
turning the power on and off to the projector lamp was not
considered advisable for several reasons: it would have
necessitated internal wiring changes to allow the change
mechanism to continue to operate; it would have drastically
shortened lamp life; and the relatively slow ignition and cooling time of the lamp would have been aesthetically objectionable. For these reasons an external solenoid-operated
shutter was used. The shutter was placed as close to the
lens as possible to minimize the amount of mechan;cal
movement necessary. The method finally used is certain to
make optical engineers wince, but proved serviceable for our
purposes. This was simply to place a metal vane operated
by a rotary solenoid in the center of the beam path. Rotating the vane to one extreme of the solenoid motion
placed it parallel to the light path and thus obstructed the
projection only with its thickness, i.e., about .02 inches.
Rotating the vane to the opposite end of the solenoid motion
completely shuttered the projector. This balancing force around
the axis resulted in a simple, fast-acting shutter. Even with
rubber cushioned stops, mechanical noise remained a problem, however.
Slides were advanced in the normal way except that the remote control push button suppl ied with the projector was
replaced with connections made from the pin jacks in the
rear of the projectors directly to the relays in the memory
unit. The latching network was omitted from these relays
to prevent the changers from cycling continously.
Estimate of System Performance. Overall, the performance
of the system was somewhat better than one might imagine
considering the lack of resources-material and human-and
the innovative nature of the experiment. Both technically
and aesthetically the project has given not only strong indications towards further study and improvement, but also
considerable encouragement as to the basic aesthetic and
practical value of this specialized system. Technically, several areas need further work:
1. The initiating systems were satisfactory, given the situation, but greater operator flexibility was needed. Particularly,
control was needed over the individual projectors-either to
cover an error in machine or actor, or to slightly modify a
cue without having to rewrite an entire tape.
2. The counting function needs study. The counter described was very noisy and its durability questionable. Electronic counting would be ideal but is out of reach financially
in most situations. Additionally, the slide changers should
indicate their respective slide numbers on the operator console.
3. Tape readout should be based on one tape with several
rows of holes per cue. Manipulating two tapes for single
cues proved to be clumsy.
4. Cue storage worked well, though probably S.C.R.'swould
be more reliable if they could be afforded.
5. The automatic control of the cover floods was not
necessary in view of the overlap possibilities of three concurrent projectors.
6. More projectors used on one projection
simplify the programming of the tape. The
the tape in the system can feed a maximum
second but the slide changers take almost a

surface would
reason is that
of 6 cues per
full second to

Power supply and distribution panel

Closeup of relay and distribution panel

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