Motion Picture Herald (Jan-Feb 1945)

Will Greater Contrast give you Better Pictures? Sharper, clearer pictures reproduced on the screen with the same brilliance and contrast that is in the film are the result of using B&L Super Cinephor f:2.0 Projection Lenses. Because they are "Balcote" coated — the revolutionary new B&L lens coating that reduces "flare" and reflections and permits the passage of more light — they permit screen images that are not "washed out" by light reflections inside the lens system. Precision anastigmatic correction adds to image quality because it insures critically sharp reproduction over the entire screen area. For the same qualities in longer focal lengths ask for Cinephor Series II . . . for a moderately priced lens with excellent correction ask for Cinephor Lenses f:2.0 or Cinephor Series I Projection Lenses. Production for victory has unquestioned priority. While this may cause inconvenience, delay, and sacrifice in filling civilian orders we know it has the unqualified endorsement of everyone with whom America comes first. Bausch & Lomb Cinephor and Super Cinephor Lenses are sold by the National Theater Supply Co., and also by leading independent theater supply houses. BAUSCH & LOMB OPTICAL CO., ROCHESTER 2, N. Y. EST. 1853 From these plants today pour a constant stream of materials for the Army and Navy. From these same plants, with the Victory won, will come that beautiful, brand-new projector which is being awaited so expectantly by thousands of America's theatremen, and a new MotiographK/lirrophonic sound system which will be a marvel for natural, lifelike reproduction. This projector will incorporate many new and startling innovations. It will set a standard for sturdiness, long life, simplicity and carefree operation. Notwithstanding its high quality it will be priced within the reach of every exhibitor. "S/nce 1896" 4431 W. Lake St., Chicago 24, III. 9 9 MOTION PICTURE SOUND ENGINEERING B 547 pages, completely covering every practical metfiod and process in present day sound engineering. Every detail of apparatus and its arrangement is minutely explained and profusely illustrated. Here is the practical answer to the perplexing problems of sound engineering. If you deal with sound at all, you should have this authoritative treatise! $6.50 POSTPAID QUICLEY BOOKSHOPrag ROCKEFELLER CENTER. NEW YORK " " street main, up to the top of the riser r where the last tap is taken off. It is standa practice in an up-feed system to ascertain fii the minimum pressure of the street main, ai to subtract from this the pressure to be he at the fixture at the highest point of the lir In these calculations, the pressure drf through the meter and service run shou also be included. The data for drop throuj the meter can be obtained from the watf company. In a down-ittd. riser system, the conditior would be the reverse of those of an up-fee' system. A down-feed system is used whei the pressure in the street mains is not gre£ enough to furnish a sufficient volume of watt for supplying the fixtures or plumbing equip ment at all times and under all loads. Th source of water supply in a downfeed syster is a tank erected on the roof. In some cas^ both the up-feed and the down-feed system' are used ; that is, the plumbing fixtures in onf; part of the auditorium are supplied direcl' from the street mains, while those in anothe|i part of the auditorium are supplied by thi tank on the roof. INSTALLING A ROOF TANK The advantage of using a tank is that if will fill gradually from a very small flow ot water, thus forming a reservoir from which a larger volume of water can be drawn in a shorter space of time than could be forced through direct from the service water main. It should be remembered that the tank on the roof should always be protected with an overflow pipe of ample size, and that the supply from the street main be controlled by a ball-cock and float or similar automatic water control device. In installing the tank on the roof it is very), important that the water line in the tank be of the proper height above the highest fixture that is supplied with water. In other words, to generate a gravity head at the highest fixture, of 15 pounds per square inch, the water line in the tank must be nearly 35 feet higher, and with the friction loss in the run included, it would become about 40 feet. When such heights are not feasible, the water pressure on the highest fixture or fixtures will . be reduced considerably. Suppose this pressure were reduced to 8 pounds ; this could operate a flushometer, but should it drop below this amount, flush tanks would have to be \ used at the fixtures, or a small pneumatic tank be installetl to give the increase in pressure. When the physical condition on the roof will not permit the placing of the tank at any great height, the size of the down-feed pipe between the tank and the highest fixtures should be amply over-sized. Where the tank on the roof is only about 15 feet above the highest fixtures, flush tank water closets or urinals have to be used if the water is furnished from the tank; and the pressure drop in the entire pipe run, from the tank down to the farthest fixtures, should not be more than about \%. pounds. Either a steel or wooden tank can be installed. Steel tanks of sizes commonly used for fire-protection cost about 70% more than wooden tanks. However, a steel tank of about 30,000-gallon capacity can be erected on a steel trestle at about the same cost as a wooden tank. Considerable saving in the cost of the support can be made by having a steel 14 BEHER THEATRES, JANUARY 6, 1945