The motion picture projectionist (Nov 1930-Oct 1931)

44 Motion Picture Projectionist March, 1931 BLUE SEAL HEAT RESISTING IMPROVED FILM TRAPS FOR SIMPLEX PROJECTORS MADE OF AN IRON ALLOY Guaranteed not to Warp under the intense heat of the Arc Spot. A necessity for the Perfeet Projection o f "Sound" Pictures B-16 — Film Traps with Sliding Double Round Corner Apertures, one Aperture for Disc and Silent Film and one cut Proportional for Movietone Film to be used with our Adaptors . $30 B-17 — Sliding Double Aperture Plate $6 B-24 — Film Trap with individual mats for silent, movietone and magnascope effect. Traps complete with all mats . $30 B-20— Master Plate to hold mats stationary. .$1.50 B-21 — Standard Aperture with Square Corners. $1.50 B-22 — Proportional Movietone Aperture with Square Corners. .$1.50 B-23 — Blank Mat (CAN BE CUT ANY SIZE APERTURE) ...$1.50 Manufactured by BLUE SEAL PRODUCTS CO.. Inc. 262 Wyckoff St. Brooklyn, N. Y. Manufacturers of Motion Picture Accessories Since 1913 By Test Proven Best I $9.00 Each Imagine! Now on their second year of giving satisfactory service to Hi-Lo lamp users everywhere from Coast to Coast. Surely there must be a reason for this preference for the GEM CONTACT JAW Designed right, made right, and priced right. Order a Spare Nmo! FOGELBERG ENGINEERING CO. 128 S. Clinton St. Chicago, 111. Sold by Reliable Independent Dealers Everywhere SOUND REELS For Perfect Protection ALL-WELDED TYPE One Unit LASTING DURABILITY Bright Cadmium Plated UNIVERSAL ELECTRIC 9-16 Thirty-seventh Ave., — All Sizes — DEMOUNTABLE TYPE Each side one unit ALL PARTS REPLACEABLE Write for quotations WELDING COMPANY Long Island City, N. Y. similar action begun in September, 1928, and based on somewhat broader grounds had been dismissed by the superior court of Montreal. The second action as originally begun involved the charge of infringement of eight De Forest patents claimed by the plaintiff to be fundamental to the use of sound on film in the talking picture art. Before trial, however, De Forest Phonofilm of Canada withdrew the charge of infringement on six of these patents, leaving in suit No. 252,491, issued to Lee De Forest on August 11, 1925, and alleged to dominate the method of recording sound on film by means of the so-called flashing lamp; and No. 279,863 issued to Lee De Forest on May 1, 1928, and asserted to cover broadly the combination of sound-on-film reproducing apparatus with a motion picture projector. Amplification the Outstanding Problem in Television Work Undistorted amplification over an enormous frequency range is one of the outstanding problems in radio television. While the ear may be fooled into accepting as perfect an amplification curve which plots like the profile of the Rocky Mountains, the eye immediately detects uneven amplification in its pictorial interpretation. Thus the best transformer coupling will not do except for crude silhouettes. The most advanced form of resistance-coupled amplification is essential for fine half-tone pictures, with a flat frequency response curve up to and beyond 50,000 cycles. Much Recent Progress Notable progress has been scored in television amplifiers, both at the transmitting and receiving ends. Aside from the proper selection of resistance and capacity values, as well as other circuit considerations, the resistors themselves have received critical consideration. The slightest imperfection in resistors, according to Jesse Marsten, Chief Engineer of International Resistance Company, gives rise to serious pictorial defects. Noisy resistors are detected by blotches in the pictures, similar to those caused by severe static. Uncertain resistance values result in upsetting the delicate gradation of half-tone pictures and breaking up the finer detail of silhouette pictures. Due to the exceptionally high amplification at the pick-up end as well as at the receiving end, the resistors are severely tested in television work. The high resistance values required make the wire-wound type too costly. The standard resistor emploved in television work is the heavy duty or powerohm type of metallized resistor the positive conduction and perfect contacts of which insure noiseless operation together with freedom from moisture due to the special ceramic enclosure.