The Cine Technician (1935-1937)

.'ovember, it)3S The Journal of the Association of Cine-Technicians 69 Rotary Picture and Sound Track Printer The printing of Sound Tracks was found to be an exceedingly critical operation, and called for the same accuracy in machine design and construction as the Sound Recorder. Also, it was found that when the conditions existed of making both negative and positive run at a dead consistent speed without vibration, a better reproduction of the picture, as well as the track, was obtained. Hence the introduction of a Rotary Picture and Sound Track Printer. This apparatus prints both picture and sound at one operation, under complete automatic control. An extreme definition is obtained, giving a softness to the picture and all the higher frequencies of sound, which is impossible with a step-by-step machine. These results are due to the perfect imiformity of speed given by a patent mechanical filter, and the accurate cutting of the sprockets to within •0002". Light values for picture and sound are controlled by means -of synchronised charts which dispense with notches and staples in the negatives. These charts are cheaper and stronger than the systems now used, and the\ last for a iumdred prints. The printer stops automatically at the finish of the run ; thus a saving of time, wear to negatives and raw stock is effected. The human error in "framing" is eliminated. The machine can be run as a single unit, or two or more can be coupled together, the mute picture negative being run on one, and the sound track on the next, with the positive over the two, giving a finished 1000 feet sound print in ten minutes. The take-offs and take-ups are integral with the machine. All the gearing is totally enclosed. The machine is chain driven through a clutch, thus avoiding risk of slip and waste of stock when starting and stopping. The exposure gate is of the curved pattern, hardened and ground to a high finish. The curve is very carefully calculated to ensure perfect contact with the gate. A slight tension on the positive keeps the two films in perfect contact without any tension being applied to the negative. Three gates are supplied with each machine, for silent, mute picture and sound track. The overaU length of each unit does not exceed two feet. The Automatic Light Control is an entirely new departure for controlling the light value on the Rotary Printer. Batteries are not required. The negative is not used as an insulator between electrical contacts, or for operating contacts of any description ; thus wear and tear to the negative due to operating the control is nil. Should the negative be notched or stapled, as is required by other methods, it does not affect the working of this control. The picture and sound track are a better reproduction than that obtained from any other make of rotary printer, this being due to the immediate change of light values, of which there are 2L The control is on a parchment paper 70 mm. wide, and runs in synchronism with the negative ; this will operate the printer effectively up to 120 ft. of film per minute. The Negative Grading Machine is for producing the perforated chart for use with this automatic control. The negative is passed over an illuminated panel, and at the same time the 70 mm. wide parchment paper is passing through a perforating gate at one-hundredth the speed of the negative ; thus 10 ft. of paper is equal to 1000 ft. of negative. (Coiitiniicd on page fi8.) Johnsons Manufacturers of Pure Chemicals for Cinematography, including AMIDOL ETOL PYRO HYDROQUINONE & GLYCI JOHNSON & SONS, MANUFACTURING CHEMISTS LTD., HENDON, LONDON MANCHESTER OFFICE: 12. QUEEN STREET. DEANSGATE THH CHEMICAL MANUFACTURERS TO THE PHOTOGRAPHIC INDUSTRY