International projectionist (Jan 1941-Dec 1942)

The time-constants of the rectifier circuits are so chosen that a change in gain of the compressor is accomplished in approximately one millisecond. Films for Recording A resume of developments in the soundrecording field would be incomplete without reference to the advances made in the manufacture of film stocks for recording purposes. The early variabledensity sound-negative records made at Warner Bros. Studio were recorded on Eastman type 1301 positive film stock with development carried to a gamma of approximately 0.4. This film was originally designed for use as a print stock, the development of which would be carried to a gamma of 2.0 to 2.4 and was, therefore, somewhat low in sensitivity for recording purposes. In September, 1932. the Eastman Kodak Company made available type 1359 recording stock which had a speed of approximately 2.5 times that of the type 1301 emulsion. This increase in film speed made it possible to reduce the recorder exciter-lamp current by an amount that increased the lamp life several hundred per cent, and decreased the variation in negative sound-track density which had previously been caused by lamp instability. The 1359 type emulsion was used by Warner Bros, until the introduction of ultraviolet recording in 1936. At this time the advantages of employing variable-area ultraviolet recording appeared sufficiently great to justify a complete change in plant recording equipment and the RCA variable-area machines were installed; At this time Eastman made available their type 1357 emulsion which had approximately twice the speed 'of the type 1301 emulsion to ultraviolet light and this stock is employed for sound negative at the present time. On October. 1937, Eastman type 1360 fine-grain positive film was tested as a negative recording stock and found to be somewhat superior to the type 1357 film in both high-frequency response and back Consult vour nearest National Theatre Supply Co. dealer in the U. S. A.; or The General Theatre Supply Co. in Canada. IransVerteK HELPS WIN A WAR The same dependable, fine performance of Hertner Transverters, which has earned the praise of world-wide projectionists, is now being built for vital war needs. Transverter is built to give years of uninterrupted service. THE HERTNER ELECTRIC CO. Exclusive Manufacturers of the Transverter 12692 Elm wood Ave., CLEVELAND, OHIO ground noise. A number of productions were recorded employing this stock for the sound negative until it was determined that similar improvements could be obtained by utilizing this stock for prints employed for re-recording purposes. In December^ 1939. Eastman announced the replacement of the type 1360 emulsion by the type 1361, a film of somewhat lower inherent contrast, and of such spectral sensitivity as to permit handling it under positive-type safelights. In all other respects this film is similar to the type 1360 emulsion and results in an increased high-frequency response of approximately 1.5 db at 9000 cps and a reduction in film background noise of approximately 6 db. In order to provide negatives from which release prints can be made in the various countries, and to provide insurance against the possible destruction of the original picture and sound negatives. CLAYTON BALL-BEARING EVEN TENSION TAKE-UPS For all projectors and sound equipments All take-ups wind film on 2, 4 and 5 inch hub reels. Silent Chain Drives THE CLAYTON REWINDER For perfect rewinding on 2000-foot reels. CLAYTON PRODUCTS CO 31-45 Tibbett Avenue New York, N. Y. it is customary to prepare duplicate negatives of the picture and sound-track negatives by photographic means. The process invovles making a composite master print from the picture and sound negatives and by a second printing operation, securing a composite duplicate negative of the original. Until recently, the composite master print was made on Eastman type 1362 lavender stock and a "dupe" negative was made from this on Eastman type 1217 panchromatic negative stock. Prints made from the duplicate negatives, when compared with the original, showed an average increase in film background noise of approximately 5 db. a loss in volume of approximately 2 db, and a reproduction loss of 6 db at 9000 cps. In the latter part of 1937. Eastman introduced its fine-grain duplicating positive stock, type 1365, and a fine-grain duplicating negative stock, type 1203. These films have been substituted for the lavender positive stock and panchromatic negative stock previously employed in making duplicate negatives and prints from this new stock show an increase in surface noise of only one db. a loss in sound level of one db, and a loss in high-frequency response of only one db at 9000 cps as compared to the original. This improvement in duplicating stocks represents a remarkable achievement in film manufacture and permits the production of prints from duplicate negatives that can not be distinguished from prints of the originals. It is evident that the exercise of the greatest care and use of the latest recording equipment and materials will FEBRUARY 1942 25