Boxoffice-May.03.1952

j
MEMOIRS OF PROGRESS
Continued from page 36
hold the crater as close as ten thousandths
of an Inch of the exact focal point.
Producins still more light meant developing
still more heat. This called for a larger
lamphouse. the redesigning for better dissipation,
and the use of materials and parts
which afforded greater resistance to heat.
Forced air cooling was adopted for the
working parts.
A JET OF AIR WAS USED
A jet of air, rather than the previously
common magnetic system, was employed to
stabilize the tail flame of the arc. This air
blows the tail flame away from the reflector,
keeps it cooler and prevents the soot
from depositing on the surface.
Here, in the Strong Mighty "90," developed
in 1949. was a king size, reflectortype,
high intensity projection arc lamp
These old timers rep
resent various stages
of development in
projectors and lamps
At top left is the
Powers Peerlesscope
projector with acety
lene
projection
lamp. At right is
the Idison exhibition
model of 1898 with
a carbon arc lamp.
The Phantascope
projector and arc
lamp produced by
Jenkins is shown at
the
bottom.
«« ••
The Strong Mighty "90" was developed in 1949.
It burns Irom 75 to 140 amperes, and produces
all the light energy today's projectors and film
can handle.
that burned from 75 to 140 amperes and
embodied all the advance engineering resulting
from 25 years of building lamps.
Here was a lamp that produced all the
light energy that today's projectors and
film could accept without damage to
either or both.
A SPOT FOR SMALL THEATRES
Another follow spot, the Trouperette. employing
the incandescent bulb instead of an
arc, was designed in 1950 for the smaller
theatres, night clubs and auditoriums where
the tremendous volume of light from the
arc was not necessary. This Trouperette
employed the same ingenious optical system
for changing the spot size that was
used in the original Trouper arc follow spot.
Celebrating the 30th anniversary of
Strong Electric, this year is, more importantly,
the 150th anniversary of Sir Humphry
Davy's invention of the carbon arc.
in w^hich he employed sticks of charcoal as
electrodes and some wet batteries as a
power supply. It was nearly 100 years later
that Cecil Hepworth employed a hand-fed
carbon arc on his Theatograph projector
which was shortly followed by a vertical
arc designed by Jenkins for use in his
Phantascope projector.
While arc lamps, because of their high
intrinsic brilliancy, have always been used
in motion picture projection, many other
light sources have also been employed.
Edison used an incandescent light in his
Kinetoscope, but on his Exhibition Model
of
1898 adopted a carbon arc.
FRENCHMEN USED ETHER LAMPS
Auguste and Louis Lumiere of Lyon,
F^-ance, used an ether lamp on their Cinematograph
projector of 1895 and even today
many of the old time projectionists will
remember the first models of the celebrated
Powers Peerlesscope projector which used
an acetylene lamp. Thomas Drummond
employed the lime light, which was simply
a stick of lime heated to incandescence by
a gas flame. Credit for the real improvement
in projection lighting must go to
Heinrich Beck of Meiningen, Germany, who
40 years ago took out patents for an arc
using a positive electrode, which was a
carbon shell or tube filled with a paste,
consisting of certain salts, fluorides of calcium,
barium and strontium.
When these electrodes were employed,
this core material was changed into a gas
which burned with a brilliancy that was
many times that of the incandescent tip of
a plain carbon electrode. Its snow-white
color accounted for the name high intensity.
An arc using plain carbons was known
as a low intensity because it burned at a
low color temperature, that is, a muddy
yellow as compared with Beck's arc.
It may be interesting to note that for the
past 30 years Strong Electric has announced
some major new development on the average
of every two years. Our engineering
department is constantly engaged in a program
of experimentation, which will undoubtedly
result in further developments
to meet any needs of the future.
As limelight and ether lamps were used
in the early days of motion picture projection,
likewise there have been recent
experiments with higher-powered, incandescent,
filament-type lamps; high pressure
mercury lamps and zirconium electrode
lamps, but none of these has ever approached
the intrinsic brilliancy of the high
intensity carbon arc.
All the development and research work
of the lamp manufacturers, collaborating
with developments by the carbon companies,
has resulted in improvements in
lamp design, to a point where the light
or energy at the film aperture is now so
intense, that before any further increases
in picture brilliancy can be attained there
must necessarily be more effective methods
of cooling the film at the aperture.
MODELS TO MEET ANY NEED
From a humble beginning. Strong Electric
has grown to become the largest manufacturer
of projection arc lamps in the
world, with specific models to meet any
field requirement.
The Strong line includes the Mighty "90,"
for use in the largest theatres and driveins:
the Mogul for screens 24 feet in width;
the Utility for 20-foot screens; the One
Kilowatt lamp for screens of 18 feet in
width; the Portable lamp for use with
portable projectors, projecting pictures up
to 14 feet in width, and the Junior High
for 16mm projection.
Strong engineers continually incorporate
latest developments and improvements into
each of these lamps, so that as they come
off the production line today they are
truly 1952 models.
That's my story and I'm stuck with it.
38 The MODERN THEATRE SECTION