Identifying materials in special effects projector

I am responsible for the conservation of an object about which I
have been able to find little information. The object is part of a
special effects projector dating from the late 1920's. We believe
the projector itself might be what was called a Brenograph Junior.
We have parts of the projector, but nothing with a name. The
projector is a simple circular metal case that mounts over the lens
of a Fresnel--a type of theatrical lighting instrument. The
projector has a motor that drives a translucent disk on which there
is a photographic representation of clouds. With the lamp turned on
and the disc slowly rotating, the image of clouds would be projected
on the ceiling of the theatre prior to and following the
presentation of the main attraction--the movie.  It was the use of
these types of projectors that distinguished the sub-set of cinemas
referred to as atmospheric cinemas.

The part of this projector I am researching is the actual rotating
translucent cloud disc through which light was projected to create
the special effect. It is 17 inches in diameter and paper thin. The
centre 8 inches of the circle is reinforced for rigidity with a
black-painted cardboard material that also holds the central drive
connections. The outside of the disk is also reinforced with black
card stock. The disc is made up of four more or less equal quadrants
of some sort of semi-transparent film material joined together with
something that looks like orange shellac. One of these connections
has failed and we can see that the joined pieces of film have been
sanded to make the overlapped edges thinner and then cemented
together with the shellac-like material. Presumably segments were
used because larger pieces of this unidentified film material were
not available. On one side of the disc there is what appears to be a
photographically reproduced silver emulsion image depicting
cumulonimbus clouds.

Our problem is that we don't really know how best to care for the
original disc or in fact what it is made of. I have had it in my
possession for about ten years and see no particular signs of
deterioration holding it flat between acid free papers. Is that all
there is to it, or should we be doing something more. We would like
to make it part of a display that will explain the "atmospheric
theatre" and its place in the early development in cinema
architecture.

In the fully restored auditorium, we will be recreating the special
effect of moving clouds on the ceiling using two replica discs and
projectors. Famous Players built dozens of these atmospheric
theatres across Canada and the United States in the early 1930's,
but few remain in tact. The Capitol Theatre in Port Hope, Ontario is
the only one remaining and operating as an atmospheric theatre in
Canada. Soon it will have the supreme distinction of having its own
1930's atmospheric special effect fully restored.

Any information about the film disc would be appreciated.

Rod Stewart
Capitol Theatre Heritage Foundation
20 Queen Street,
Port Hope, Ontario, Canada


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                  Conservation DistList Instance 17:13
                   Distributed: Monday, July 21, 2003
                       Message Id: cdl-17-13-014
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