Patent GB-389493-A (GB)
Title: Method of and apparatus for, synchronizing sound and picture films
IPC: G03B31/00
Filed: 1931-06-08
Abstract: 389,493. Associated sound and kinematographic picture films. NAAMLOOZE VENNOOTSCHAP KUCHENMEISTER'S INTERNATIONALE MAATSCHAPPIJ VOOR SPREKENDE FILMS AMSTERDAM, 43, Mauerstrasse, Berlin. June 8, 1931, No. 16716. Convention date, June 7, 1930. [Class 40 (ii).] In order to remove errors in conformity between picture and sound records by omitting or repeating certain individual images occurring on the picture film, those sections of the picture film in which the discrepancies between the pictures and the associated portions of the sound record are greatest are ascertained and marked, the markings being used, in the production of a corrected picture film by copying from the original film, to control automatically the omission or repetition of the marked pictures ; the total length of the corrected picture film thus produced is the same as that of the original film. In carrying out the invention, the picture and sound films may be first inspected by driving them together, side by side, by means of a common feed sprocket, so that by a direct optical comparison of the two records those sections of the picture film where the picture record lags behind or leads with respect to the sound record may be noted and marked accordingly. The markings may be in the form of two sets of perforations, one set on each edge of the film, as shown in Fig. 5, the holes 61, 63, for example, showing which individual pictures should be omitted and the holes 66, 68, 72, 73, 74 showing which pictures should be copied twice, to bring the two records substantially into agreement. The comparison of the films may be facilitated by feeding them through a casing provided with adjustable indicating pointers which are slidable in the direction of the length of the films, Fig. 8 (not shown). Instead of inspecting the sound film directly by optical means, it may be compared with the picture film by reproducing the recorded sound by photo electric apparatus as the two films are fed in synchronism, an auxiliary strip being, fed at the same time on which strip pencil markings or the like may be made to indicate what alterations of the picture record are necessary. Another alternative consists in preparing on a strip moved synchronously with the sound film a transcription of the words recorded on the film, the written wording being spaced in correspondence with the sound record. A comparison of the picture record with the written text is then made, and discrepancies are shown by markings on the picture film as described above. Hand-operated punches suitable for perforating the film are described and shown. An apparatus in also described, Fig. 9 (not shown), whereby the perforations on the edges of the picture film are made by automatic punches, which are controlled according to the settings of pointers adjusted along the picture film and a sound record transcription film as these are run side by side. Fig. 6 shows an apparatus for photographically printing a picture film which has been marked in the manner shown in Fig. 5 and for automatically controlling, by means of the perforations, the omission or double copying of individual pictures as required. The marked negative film 80 and the print film 81 are fed together past a printing aperture 88 which is illuminated by a lamp 86. The films are fed by sprockets 85, 83, driven by a motor 82 through belts as shown, electromagnetic clutches 107, 107a being provided in the transmission from continuously running shafts 84, 84a to the sprockets 85, 83 respectively. Circuit closing means associated with the sprockets cause the lamp 86 to be switched on intermittently, to effect instantaneous printing, once during each revolution of either of the sprockets. When the end of a spring-actuated lever 89 enters a hole in one edge of the film 80, contacts 91 are closed and cause the drive for the sprocket 85 to be declutched for one revolution of the shaft 84, the film 81 continuing to run. A picture on the film 80 is thereby printed twice, and this occurs each time a hole in the film passes the lever 89. A lever 90 operates in a similar manner to stop the film 81, by controlling the clutch 107a, a shutter 101 being simultaneously actuated in order to obturate the lamp whilst the film 81 is stationary ; the shutter is actuated by an electromagnet 100 and is controlled by a dashpot. By this means the printing of a picture is omitted each time a perforation in the film passes the lever 90. I n a modification of the apparatus shown in Fig. 6, printing is not effected directly from the marked film, but this is used to control the printing of a corrected film from a duplicate of the marked film. The Specification as open to inspection under Sect. 91 describes a device comprising an apertured slide which is movable along a combined sound and picture film, the upper edge of the slide and the lower edge of the aperture respectively indicating corresponding parts of the two records. The Specification also describes " a device for lengthening the sound record in the manner of the superspeed camera.." In this device the sound film, moved at either a lower or a higher speed than usual, is scanned by means of a rotating diaphragm having a series of radial slits. Means are described whereby " the slowed-down or speeded-up sound renderings obtained may be used for making new sound records which may be rendered in apparatus of the usual type at normal velocity." This subject-matter does not appear in the Specification as accepted.