GB352471A - - Google Patents

Abstract

352,471. Combined sound and picture films. STAHL, C., 37, Laubacher Strasse, Wilmersdorf, Berlin.-(Assignee of Freund, B. ; 30, M³nchener Strasse, Sch÷neberg, Berlin.) March 31, 1930, No. 10182. Convention date, April 2, 1929. [Class 98 (ii).] A combination sound and picture film record is made as a negative by first recording the sound and pictures on separate films, developing one of these, then transferring the developed record on to an unexposed portion of the undeveloped film which bears the other record, and finally developing the latter film. The transfer may be effected either (1) by contact printing from a positive derived as an intermediate print from the originally developed negative record, or (2) by using a reversal film for the initially developed sound or picture record, so that this is formed as a positive in the first instance, or (3) by using an electro-optical copying process, whereby a negative can be directly transferred as a negative. Fig. 3 shows a method of carrying out the process, in which a negative sound record 40 is passed across a beam of light from a source 41, which beam falls on a photo-electric cell 44. This cell controls, through an amplifier 45, a lamp 46, by means of which a replica of the negative sound record is formed on the portion 3 of the undeveloped picture film 1. Fig. 2 shows a method of contact printing from an original sound film 10 on to a shorter film 18. Light is directed on to a point 17 at which the films 10, 18 pass together over a roller 23, the film 10 moving more rapidly than, and in the same direction as, the film 18. In Fig. 5 is shown a device for enabling the correct printing exposure to be determined. A rotary shutter 60 carries a number of light filters 61, 62, &c., of varying density, separated by opaque bars 70. The shutter is mounted on a spindle 84 carrying a pointer 97 which moves over a scale. Light from a source 75 passes through the shutter, and is focused by an optical system on the print film 80 (the film from which the print is being made not being shown). A test print is first made whilst the shutter 60 is rotated intermittently, so as to produce a record which, after development, has the appearance shown in Fig. 4. By noting which of the separated sections 50, 51, &c., of the sound record has been correctly exposed, the shutter can then be set, by means of the pointer 97, so that the light filter which gives the best result intercepts the beam.