Moving Picture Age (Jan-Dec 1922)

16 MOVING PICTURE AGE June, 1922 Grealer lHar\ .4" Square Goes Vhru. .per lure Heat is reduced to a minimum. Since the light-giving elements are entirely enclosed in an airtight glass bulb, it stands to reason that there cannot be carbon dust and gas. Therefore, the working conditions with a projector equipped with Mazda lamp are well-nigh perfect. „ .4 Square PicK-up area Aperlure BlacKem-nd does 'not cut 5o« Rays Outside the "Pickup" Area Are Shown Bent by the Condenser So That They Do Not Pass through the Aperture ber of advantages are claimed for the machine, which, by the way, has been developed by one of the pioneers in the motion-picture field. All in all, the semi-professional projector is excellent where a professional machine is too large and too formidable to be tackled by novices, and where the portable machine is inadequate. Its weight, 40 to 60 pounds, is certainly within reason, and makes it portable if necessary. THE INCANDESCENT LAMP VS. THE ARC AFTER several years of intensive development and experimentation, projection with Mazda lamps has now become not only practicable, but representative of the most satisfactory and efficient method, according to the manufacturer of Mazda lamps. The Mazda lamp, continues our authority, brings into this service those features that have won it an enviable position in store, factory, and street lighting, etc. The projection, as to color, definition, and intensity, is adequate and extremely well suited to the demands of the theatre. But for our purpose we are primarily interested in the non-theatrical application, and here the Mazda lamp is at its best. Until recently this type of lamp has been widely employed in portable and semiprofessional machines, but with the most recent advances it is now said that the Mazda lamp is available for the professional machines. Just so long as the arc lamp had to be employed, the semi-professional, the portable, and even the heavy-duty large-capacity professional machine were hardly suitable for non-theatrical applications. But the introduction of the incandescent lamp of the Mazda type has altered the entire projection field and has brought all classes of projectors within the scope of the non-theatrical exhibitor. First of all, the Mazda lamp is less expensive to operate. There are no carbon clamps or asbestos lead wires to be replaced, while the mirror may need replacement but two or three times a year. With proper adjustment such annoying features as perceptible flicker or uneven illumination need never be encountered, since the light source is perfectly steady and not subject to "travel." The light has a soft, pleasing tone, bringing out the depth of the picture. The rendition of colors is also most satisfactory. The resulting restful effect, as well as freedom from eyestrain, makes this type of projection popular with the audience. One BlacKening may .cut down light The Power's Projector, Using the G. E. Unit for Mazda Lamps Wasled Rays y Useful Rays Prismalic Condenser Where BlacKemng may lake place Filament Snort distance Comparative Merits of Tubular and Round Bulb According to the information compiled by J. A. Sommers, Fighting Service Department, Edison Famp Works, at Harrison, N. J., the new G-E incandescent lamp projector, with the 900watt Mazda C lamp, can be used successfully in auditoriums and halls that have a maximum main floor seating capacity of 1,000, for a picture not over 16 feet wide and a throw not exceeding 120 feet. It is said to give better results than an alternating-current arc, and under average operating conditions is the equal of a direct-current arc up to 50 amperes. Indeed, the low power consumption, often avoiding the necessity of heavy, special wiring or of overloading the circuit, is highly important. The simplicity of the lamp house also goes a long way toward making the Mazda-equipped projector especially suitable for non-theatrical applications. The profession-projector Mazda lamps are made in the 900-watt, 28-32-volt Mazda C (gas-filled) lamps, which has been found to meet the requirements of the large auditorium and hall, including the theatre ; and the 600-watt, 20-ampere, 28-32-volt Mazda C lamp, where a smaller picture or a low intensity of light will suffice, such as in churches, schoolrooms, and small auditoriums. The average burning life of these lamps is 100 hours under normal operating conditions. The bulbs are made in the long, tubular form, instead of the round globe. To begin with, the blackening takes place at the tip of the lamp, and the farther away the tip is kept from the filament, the more likely the filament is to shine through clean glass and thus not drop off in effective illumination. Then the narrow tubular form also permits of bringing up the condenser far nearer the filament than is the case with a round globe. It is interesting to note that a special tvpe of condenser has been developed for use with the Mazda lamp, providing for the utilization of this illuminant so as to produce a stronger illumination on the screen. The area of the light source that the special prismatic condenser lens will use most efficiently is a circle four-tenths of an inch in diameter. Only a small proportion of the light emitted from a source not within this limit terminates as illumination on the screen. Through the design adopted for the lamp filament, the largest filament surface is presented within the useful limit. As (Continued on page 23) Mirror Prismatic Condenser Lamj Lamp How the Mirror Utilizes a Portion of the Light That Would Otherwise Be Wasted by Redirecting It through the Light Source toward the Condenser important consideration is the fact that the Mazda lamp burns with equal brilliancy on alternating or direct current. Therefore, when alternating current is available no auxiliary equipment, such as a motor-generator set or synchronous converter, is required. A small hand-operated transformer that forms part of the lamp adapter serves to regulate the current requirements. Optio Axis Optical System for Mazda Motion-Picture Lamp — Professional Projection