International photographer (Jan-Dec 1934)

Twenty-four T h INTERNATIONAL PHOTOGRAPHER September, 1934 MOTION PICTURE SOUND RECORDING (Continued from Page 21) shaft of the worm wheel, the large sprocket that carries the film past the light beam is driven through a special mechanical filter. This mechanical filter is to iron out any variations that may occur in the speed of the driving motor and to compensate for any imperfections in the driving gears. The heavy flywheel built directly on the motor shaft likewise helps to steady the speed of the motor. All of this mechanical filtering has for its object the elimination of "flutter" in the sound track, which is produced b\ any intermittent variations in the angular velocity of the film as it is carried past the point of exposure. Film Speed Must Be Constant The speed at which the film is pulled through the recording machine is precisely ninety feet a minute, corresponding to a driving motor speed of 1200 revolutions per minute ; and in an ideal recording machine, the film would pass the exposing light beam at this speed with absolute uniformity and steadiness in rate of travel. The uniform rotation of the sprocket that carries the film past the light beam is not affected by variations in the rotation of the other, the feed sprocket, due to the two loops that are left in the film between the two sprockets, because any variations in the rotation of the feed sprocket from normal will be absorbed by these two film loops and have no effect on the angular velocity of the sprocket carrying the film past the light beam. The feed sprocket not only draws the film from the upper magazine, but it feeds it down to the lower, or take-up, magazine. If a steady sine wave representing any audio frequency, such as 1000 cycles per second, is recorded and there is any flutter present in the recording machine, the recorded sound when it is projected will vary up and down in tone. The same thing happens to any sound that is recorded in a machine in which there is flutter present; but it is more noticeable with a steady tone because of the pureness of the note. The next chapter will continue with the discussion of film recording, going on through a description of the constant light source and the light valve assembly. MOTION PICTURE PERSONNEL AND PRODUCTION EXPENSE (Continued from Page 22) Extra Talent, Music Director, Musicians, Copyist and Supplies, License Fees, Production Staff, Cameramen's Salaries, Rentals, Sound Recorder and Assistants, Miscellaneous Sound Expense, Art Supervisor, Set Designing, Set Operation, Set Striking, Wardrobe Designing, Wardrobe Purchased, Wardrobe Manufactured, Wardrobe Rentals, Wardrobe Lost and Damaged, Make-up Salaries, Make-up Material, Properties Rented, Properties Manufactured, Properties Purchased, Lighting Labor, Lighting Current, Lighting Supplies, Lighting Equipment Rentals, Laboratory, Picture Negative Raw Stock, Picture Negative Developing, Picture Positive, Developing and Printing. Still Negative and Prints, Sound Track, Positive Raw Stock, Sound Track, Developing, Sound Track, Printing, Still Negative and Prints, Check-up and Master Print, Titles, Editing Salaries, Preview Expense, Projectionists' Salaries, Sound Effects Salaries, Material, Rentals, Photographic Effects Salaries, Material, Contract Work, Stock Shots, Still Prints, Miscellaneous, Transportation for Art Department, Property Department, Wardrobe, Electrical, Location, General Transportation, Location Rentals, Railroad Fares, Hotels and Meals, Miscellaneous, Miscellaneous Meals, Tests, Unclassified Expense, Royalties. Special Insurance. The above items vary in cost according to the nature of the Production. After the production is made and previewed there is still a very large expense wrhich must be charged against it before the picture is released to the public. Release prints, sometimes as many as two hundred, are made for American distribution ; eleven are made for foreign distribution and several lavenders to be used as duplicate negatives. In all two hundred and fifteen prints ; then to this sum is added exploitation and sales expense. Making a successful feature motion picture requires a highly specialized group of people and complete harmonious co-operation from all concerned. The Roto-Tank showing Film and Separator 16 and 35 mm. Positions of Rotor The New HOLLYWOOD ROTO-TANK Specially designed for users of Contax, Leica, Military Cameras, 16 mm. and location tests on sound and action recording units. A maximum of agitation is produced in this unit, insuring shorter developing time with color separations and gradations unobtainable by other methods. No pre-soaking, no air bells, no streaks. The entire unit is constructed of heavy bakelite of low conductivity. 25 feet of 35 mm. or 50 feet of 16 mm. Price— Postpaid in United States $25.00 For details regarding the Roto-Tank and larger units write ROY DAVIDGE FILM LABORATORIES, Ltd. 6701 Santa Monica Blvd. Hollywood, California Please mention The International Photographer when corresponding with advertisers.