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1953-54 Theatre Catalog, 11th Edition, Page 282 (246)

1953-54 Theatre Catalog, 11th Edition
1953-54 Theatre Catalog
1953-54 Theatre Catalog, 11th Edition, Page 282
Page 282

1953-54 Theatre Catalog, 11th Edition, Page 282

The first section (C) represents the discharged gases of blue and purple color. Section (A) represents the snow-white area formed in, and directly adjacent to the crater floor of the arc. Section (B) represents an area formed by the glowing carbon surrounding the crater which is yellowish in color.

To produce a snow-white image focusing of zone (A), it is necessary to focus only zone (A), without including zones (B) and (C) and their undesirable color characteristics. This condition of separaof the zones can only be accomplished by the utilization of a highly accurate ellipsoidal curvature as nearly free from aberrations as possible.

This high degree of curvature correction was arrived at and held to in production by means of special optical light testing equipment, designed and built by the manufacturer.

FIGURE 1 REPRESENTS a high-intensity type are with the an: colors divided into three lanes.

Testing Equipment

The testing equipment consists of a rigid rack on which a reflector may be placed in an inverted position. Directly below the reflector, at its focal point, is situated an incadescent bulb having a coiled wire Filament one-eighth inch long.

TESTING EQUIPMENT is very important in the manufacture of metal reflectors. Seen here is an optical testing device used to check accuracy.

Further down the rack, at the proper working distance position for the reflector being tested, is located a long focal length camera lens with adjustable iris. Below this pointewhere the camera lens comes to focuseis a small screen on which appears an image of the illuminated reflective surface of the reflector under test. Testing for correctness of optical curvature is made with the iris closed down to its smallest opening (approximately one-eighth inch diameter). Under this condition it means that every square inch of reflecting surface area must be focused through this small iris opening-if an illuminated surface image is to be seen on the screen below. The slightest distortion of the true elliptical curvature will create a shadow area in this image, which means that not only must the curvature be true, but also the base material itself must be thick enough to be rigid and to thereby hold its position without springing or warping.

This test equipment is also used for close inspection to the texture of the polished reflecting surface. In this manner, it is possible to check for metal flaws, faulty grinding, faulty polishing, and even faulty electro-plating. During the course of production metal reflectors must undergo four individual checks in this optical testing device. Consequently, it is possible to maintain a very high standard of production.

This new projection reflector was immediately accepted by the motion picture industry, not only from the standpoint of dependability, but also because of the economy angle. With the metal reflector no periodic replacements were required due to breakage. Therefore, no spare reflector was needed for such an emergency.

As time went on, the metal reflector proved itself to be even more rugged and dependable in the field than the manufacturer had anticipated, By September 1944, the thousands of successful installations had proven beyond a doubt that this metal reflector 'as a far more dependable and economical projection reflector than the back-silvered type currently in use. The final proof of the statement was evidenced by the demand for the refinishing of worn and scratched metal reflectors that had been in constant use anywhere from six to 10 years. In line with this demand, a rehabilitation service was introduced. This constituted

1953-54 Theatre Catalog, 11th Edition, Page 282