US2025658A - Process for the production of a colored sound film - Google Patents

Description

Dec. 24, 1935. B, GASPAR 2,025,658

PROCESS FOR THE PRODUCTION OF A COLORED SOUND FiLM Filed Feb. 21, 1933 DEVELOPED BUT IVOT F/XED h:

M] 1 r 11) 1 FIXED y l [DENT/CAL. TREATMENT 0/ SOUND TRACK AND P/cTU/EE:

DYESTUFF I lg: DE-STEOYED, WHERE METALLIC SILVER SILVER IS PRESEN STILL PRESEAHT DYESYUFF SOUND P/cTu/QE RECORD Bela Gagba/r;

Patented Dec. 24, 1935 v UNITED STATES PATENT OFFICE PROCESS FOR- THE PRODUCTION OF A COIDRED SOUND FILM REISSUEB In Germany February 19, 1931 Processes are already known in which colored sound films are reproduced, but their production is extraordinarily complicated. Moreover, it has hitherto been difficult to combine a colored picture and a black sound strip or track laid in different emulsions. The present process enables a colored sound picture and a black-and-white sound strip to be combined in one film strip in a simple and faultless manner. Several processes are known (see, for example, my prior Patents Nos. 1,956,122, 1,956,017 and 1,985,344 and my prior applications Serial No. 572,232 filed October 30, 1931 and Serial No. 646,212, filed December 7, 1932), in which there is employed a silver halide material comprising a plurality of layers and having dyestuffs or dyestuif-forming substances incorporated therein, these substances being, after the production of the silver image in the said layers, converted into colored images.

its preferred forms I employ the materials and the processes set out in my said prior patents and applications. The said processes consist in forming the dyestuif image in a manner dependcut upon the silver image by local formation of the dyestufl from dyestufi' forming substances or by locally discharging the difiusely distributed dyestufl or dyestufl-forming substance at the image or non-image parts in proportion to the metallic deposit present,'w hereupon finally there is discharged the silver leaving a pure dyestufl'.

The use of light-sensitive films having the requisite color substances already incorporated therein offers considerable advantages over the other known process of coloring the film subsequent tothe formation of the silver image, because a much greater degree of certainty is ob- ,tained that the color substances are evenly dis- 40 tributed and, furthermore, the production of the colored image is materially facilitated. The term color substances as employed in this specification-refers to all substances which are capable or supplying dyestuif images, i. e., both finished dyestuifs as well as dyestuff formers.

Now although the use of layers which already contain color substances prior to the exposure offers particular advantages in the production of colored images, certain dlfilcultles have been ancountered in producing a satisfactory sound record, as with similar treatment of the visual and sound record portions of a film the sound record would also be a colored one, and particular measures are necessary to obtain a black and white sound record in a film which contains the color In carrying out the present invention in substances at an initial stage. The drawing is a flow sheet diagrammatically illustrating the process.

In order to obtain a well-defined sound strip, it is necessary that it should be black-and-white, 5 because the blackening curve is very diflicult to reproduce free from distortion with a colored sound image; this difllculty occurs especially in the case of the so'-called intensity process. For this purpose, according to the invention, only the 10 track portion of the film strip is converted into a colored picture whilst, at the position of the sound track, the conversion of the silver image into the dyestufi image is omitted. According to the invention, this is eifected with the em- 15 ployment of the application of a resist that prevents the penetration by chemical substances which would efiect the conversion of the silver image into the dye image. This resist may consist of, for example, a layer of alcoholic varnish 20 or of a fatty substance such as, for example, tallow or wax. It is, in addition possible to employ purely chemically active resist agents; for example, an oxidizing bath is employed for converting the silver picture into a dyestufi picture. 85 In this case, a resist may be employed which consists of a thickening agent-e. g., gum arabic and sodium hydrosulphite, i. e., an agent that acts in a chemically opposite manner, in this case a reducing agent. Obviously, other chemically active resist agents may be employed for attaining the same object, but it is also possible to re-convert the already formed dyestufi' image (consisting of dyestuif and silver salt) into a silver image with previous, subsequent or simultaneous destruction of the dyestufl if the following is applied at the position of the sound strip:-sodium hydrosulphite alone or with amidol. It is possible in the case of a colored sound picture at the place of the sound records which consists of a 40 black silver band, to allow the dyestufi to reman by means of a local resist in all parts of the layers, by protecting it before its destruction, or the following method may be adopted. The dyestuif'is destroyed in, say, two layers so that 45 only the third remains colored. The color that is chosen in the particular case is immaterial and only depends on the nature oi the sensitivity of the photo-electrfc cell. A color may be selected which is suitable for the employment 50 of invisible rays such as the ultra-violet and the infra-red rays.

What I claim and desire to secure by Letters Patent of the United States is:-

The method of producing color kinematog5 E Y i records into a color image, converting the metallic silver in the visual and sound records into silver salt, treating the sound record only with a reducing substance to reconvert the silver salt into metallic silver, and thereafter dissolving the silver salt from the visual record portion by treating the film with a fixing bath.

1am GASPAR.

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