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Projection Technology Since The Golden Era by David Kilderry

Since the golden era of the 30s, 40s, and 50s there have been many technical advances in the cinema. The
average patron is aware of the progressive changes in picture and sound, however a transformation has occurred
behind the scenes in the bio box which seldom finds itself in the spotlight. All facets of the projection booth have
witnessed significant changes, which enable reliable cost efficient presentation in today's modem cinemas.
These changes are the largest factor in enabling Multiple manning in today's bio boxes. The current boom in multi
cinemas would have been impossible if we were still reliant upon the traditional 'bio' equipment which served
for so long.
From the 1930s until the late 1960s, whether they be Hardtop or Drive-In, the projection room consisted of
essentially the same basic equipment. Two projectors or machines requiring changeovers, carbon-arc
lamphouses, valve amplifiers, manual change carbon-arc slide machine and no automation. In the majority of
cases this setup required the services of a projectionist and an assistant. Constant thread-ups, carbon changes,
spool rewinding, slide shows and operations required for the presentation of the programme, occupied the duos
shift. For over forty years in the large single screen theatres this is what took place in the projection booth.

Since they took over from limelight, carbon-arcs in their various forms provided the light source for the projector.
From low intensity, hand feed to the High intensity auto feed with rotating positimes, carbon-arcs had reached
their Zenith by the late 1960s. It was about this time that the first Xenon-arc lamps appeared. The Xenon differed
greatly from the carbon in that it was enclosed in a glass envelope and required no constant adjustment or
replacement. A Xenon could burn for over 5000 hours whereas a carbon rod would last no longer than an hour.
The high initial cost was baulked at by many however the cost savings soon became apparent. Among the first
to install Xenons was the Dendy Collins street. By 1983 with the closure of the Bercy all major c.b.d. theatres
had changed to Xenons for film. although carbons remained for slide presentation up to 1988 in some theatres.
A few suburban and country cinemas still use carbons today.

The industry for years had been trying to extend the running time of the film through a single projector. With the
advances in carbon-arcs film spools had gone from 2000 feet (20 mins) to up to 6000 feet (60mins) between
changeovers. The introduction of the xenon however finally enabled a one projector installation. An entire
programme of feature, shorts & ads could run in a single projector, as there was no need to replace carbons.
Various devices started to appear, from large 13000 ft spools placed traditionally above and below the projector,
to the radical platter system where the film lay horizontally on a large plate next to the projector. In the mid 70's
Hoyts installed platters in their city theatres although the second projector in most cases was left in situ. This
provided added flexibility and reliability. The first half of the show ie ads and shorts were run on one machine
and the feature on the platter through the second projector.
With the opening of the Russell cinemas in 1978, G.U. employed 'towers' for their long play film transport
systems. This simply consisted of two large spools mounted on a pedestal or 'tower' behind the projector. This
was more cost effective that a platter, however it required a 20 minutes rewind at the conclusion of the show.
The platter system rewound itself during projection, so as soon as the film was off the screen it could be re
threaded immediately. The MUT system also utilises large spools however these sit alongside each other rather
than one above the other. All these systems are in use today but the platter is the most widely used because of
its flexibility and gentle handling of the film.
The projector itself has also seen many advances. Spool boxes began to disappear as flammable nitrate film
went out of circulation. Motorised, multiple lens turrets now occupy the front of the projector, able to rotate from
widescreen (non- anamorphic) to cinemascope in around two seconds. Motorised aperture plates slide across
the gate as the lens rotates. Various pulse heads and scanners provide information to the automation and digital
sound units respectively. The projector head is no longer enclosed behind a glass door but is open for easy
threading and cleaning access. Plastic and alloys have replaces steel in sprockets, pad rollers and even the gate
area. Solenoid activated changeover mechanisms are now operated remotely from the panel on the wall or the
automation unit In addition to the 4 channel optical sound, digital sound is now replacing the magnetic
penthouses on projectors. Despite these advances older style projectors eg, Kallee, c & W, Century, still operate
with xenon lamps and various long play mechanisms.

In the late 1960s in unison with Xenon's and long play devices, Automation units started to appear. In various
forms these devices 'read' metallic strips stuck on the film which in turn activate a function. Lights up and down,
sound, curtains, projector start/stop, lens turret, even foyer announcements were all soon controlled by the
automation unit. Timers, pushbutton, pin matrix, and computer types all varied in operation but carried out the
same functions. Perhaps the slide projector has seen the most dramatic transformation over the years. Because
it was always viewed as secondary to the film projector, its changes have occurred slower and more erratically
than other aspects of the bio box. Indeed there are still hand-feed manually operatec carbon arc slide machines
which date from the 1930's in operation today. Xenon lamps and automatic slide cha Je mechanisms appeared