Moving Picture World (Nov-Dec 1927)

46 MOVING PICTURE WORLD F. H. Richardson ’s Better PROJECTION “ Better Projection Pays ” At Your Box Office J.H. Hallberg Explains Lantern Slide Specialty MY dear Richardson : You recollect that on your last visit I exhibited to you the arrangement for lantern slide projection as provided for in the Hallberg Reflector Arc Lamp. You thought the devise to be of considerable merit and asked of me to provide illustrations with descriptions of it for use in the columns of your department, so here goes. “In the accompanying schematic illustrations, on opposite page, figure I. is a plan view illustrating position of the units for picture projection. Figure 2. is a front elevation showing the slide attachment swung out of the way for picture projection. Figure 3. is a plan view illustrating position of the units for lantern slide projection. Figure 4. is a front elevation showing lantern slide attachment and condensers swung into position for lantern slide projection. In referring to Figure 1 (a) is a cross section of the lamp house casing: (b) is a mirror reflector correctly designed to concentrate the illumination at the aperture (c) for the film: (d) is the (+) carbon; (e) is the (-f-) crater: (f) is the negative carbon: (g) is the cone of light from the (-}-) crater reflected and concentrated at the aperture (c). The foregoing constitute the units involved while projecting the motion picture. Again referring to figure 1. there is a separate right angle carbon arc lamp at the side of the main projection lamp and (h) is its ( — j— ) carbon; (1) the negative carbon; (j) the rod for fitting the right angle arc lamp, which is used exclusively for sterio projection; (k) is the swinging condenser mount within which is mounted the proper condensers together with the slide carriers (l) swung out of the way while the motion picture is projected as illustrated in figure 2. where the optical axis is indicated by (d) ; the motion picture light beam is controlled by dowser (p). When it is desired to project lantern slides, the arrangement of the units will appear as in figure (3) and figure (4), and the same letters are used for illustrating the parts. The right angle sterio arc lamp is connected in multiple with the reflector arc lamp, so that when the condenser mount is swung from position figure 2. into position, figure 4. this movement also brings the right angle arc lamp closer to the reflector lamp, and in the exact position required for the condensing lenses and the lantern slide, and then when the carbon feed rod (j) provided with handle Iq) figure 3. is turned to the left, the carbon (1) touches carbon (h) allowing the sterio arc to be struck and then the unit is ready for stereopticon slide projection. The entire unit works automatically in all respects with one single motion except the striking of the sterio arc which is a separate operation. The sterio arc lamp uses the carbon stubs left from the reflector arc, and the sterio arc will maintain an arc for at least 5 minutes without attention after once started. Those who understand stereopticon slide projection realize that this is the only arrangement that affords 100% efficient slide projection, and also that the slide may be pro jected indefinitely because the light distribution is perfectly even and therefore the temperature is uniform there being no “hot spots” on the slide to crack it. The Hallberg stereopticon attachment is therefore an entirely separate right angle arc lamp with condensers and slide carriers, simply mounted within the standard Reflector arc lamp house and on this account there is no necessity for moving the mirror reflector towards or away from the (+) crater or in any other way disturb the adjustment of the reflector projection lamp when projecting slides as is necessary with other systems using the reflector arc for stereopticon projection.” Support American Projection WHEN the American Projectionist first came into the field this department welcomed it cordially. It was recommended by this department, which did what it could to help get it support. It was a good little paper. Later for a short while it fell under the editorial management of a man who saw fit to attack this department, its editor and the Moving Picture IV orld. His reasons were probably best known to himself — at least no one else seemed to quite understand them. Anyhow he succeeded in injuring no one but himself, so1 that was that. The paper is now under a different and very able editorship and has, by its present course, repudiated what was done. I doubt if it will ever happen again and this department again recommends it to your favorable consideration. The little paper is a monthly. \ ou may obtain sample copies by either addressing this department or the American Projectionist, 158 West 45th street. New York City. Get behind it, men, and give it your support. It is well worth its small subscription price and anyhow should have your support. Has a Nice New Dress The American Cinematographer, official paper of the American Society of Cinematographers, Inc,, published at Hollywood. California and edited by Silas Edgar Snvder. has come out with a bran-new, very snappy dress in the shape of a 3-color cover. My compliments to Editor Snvder. The paper, which is in its eighth volume, is very deservedly an authority in affairs cinematographic. It has done much to aid cinematography and should have the hearty support of the Cinematographers and of the motion picture industry. Bluebook School Note This week, to let you have the advantage of Mr. Hallberg's drawings in good size, the Bluebook School questions and answers are out : next week they will be on the job again.