US2263009A - Gold sound track in motion picture film - Google Patents

Description

Patented Nov. 18, 1941 corn scum) TRACK IN MOTION PICTURE FILM Leopold D; Marines, Rochester, N. Y., and Leopold Godowsky, Jr Westport; Conn., assignors to Eastman Kodak Company, Rochester, corporation of New Jersey N. Y., a

No Drawing. Application October 5, 1939, Serial 4 Claims.

The invention relates to a method of recording sound in photographic materials and especially to the recording of sound in multi-layer materials for colour photography.

The recording of sound on motion picture film containing a plurality of layers which are processed to colour has heretofore presented difliculties, due to insufficient absorption by any of the In Great Britain January 23,-

three dye images of light in the region to which I the photo-electric cell is sensitive. Moreover, the characteristics of contrast and density desirable for the sound track are seldom compatible for those required for optimum picture quality, and this is "particularly true where the multi-layer material is processed by reversal. In copying the sound track, moreover, it is generally considered desirable to form the positive sound track by' printing from a negative rather than to print from a master positive and then to reverse the printed image.

Various methods have been proposed for the production of sound track images in multi-layer photographic film one of which is described in our prior U. S. Patent 2,143,787, granted January 10, 1939, in which the sound image is formed of silver sulfide. The disadvantage of this process is that a negative sound image cannot be formed directly (or a positive image in the caseof a print made from a negative) since it is necessary to start with a halide in order to sulfide the sound track. If it were desired to form a negative sound track by this method, it would be necessary to remove the silver halide after negative development and rehalogenize the metallic silver in order to obtain a silver halide upon which the sulfiding bath could operate.

According to the present invention, the negative silver image which is formed in the sound track by first development is locally converted in the sound track area to ametallic or metal salt image which will survive the the subsequent processing baths to which the picture area has to be.

first development of the negative image. For this purpose a motion picture film may be squeegeed by air or mechanical means to remove excess moisture immediately after the first development. edge of the film where the sound track is present to convert the sound negative silver image into an image which is not affected by the subsequent processing baths, while leaving the picture area unaffected so that the whole film may thereafter be processed as usual in subsequent baths. This may be accomplished by dipping the edge of the film carrying the sound image into a gold toning solution, or by an edge applicator such as that described in our U. S. Patent 2,143,787, granted January 10, 1939.

The sound track may be either a negative or a positive, and may-be obtained by printing from a negative sound image. The sound track area may be exposed only to blue light prior to development, so that in the case of a three-layer film having a blue-sensitive top layer,- the sound image is mainly in this layer, thus resulting in improved definition and sound reproduction.

A particularly suitable toning solution is one containing gold chloride, which rapidly causes replacement of the negative metallic silver by gold which survives subsequent processing solutions. The toning solution may contain from 1% to 20% of gold chloride, as a very small amount of solution suffices to convert the image. After edge application of such a solution, the film may be spray-washed to remove excess gold solution, the wash water being collected for recovery of unused gold.

To avoid spreading of the toning solution to the picture area, the toning solution may contain loading agents in order to control its difiusion,

as described in our U. S. Patent2,059,887, granted November 3, 1936. Another method is to provide by pre-exposure a black metallic silver line separating the sound picture area, the function of such a line being to exhaust the spreading gold solution.

When the sound track is treated by gold toning it has been found advantageous to employ for final silver removal a weakly-acid terrocyanide bath or, better still, a copper bromide bleaching bath which may consist of a solution of 25 grams of cupric chloride and 25 grams of potassium bromide, dissolved in one litre of water.

The gold toning method described in this specification may be used with various multi-color processes one of which is described in our prior A toning solution is then applied to the patriifanaa'z'e; granted April '5, 1938. 1' Our'method may, however, be used with other color processes and itis to be understood that our invention is limited only by the scope of the appended claims. 7

We claim: i, 1. The method of forming sound and natural color picture images in a film having a plurality of layers sensitive to diflferent spectral regions on.

one side of a support which comprises forming a metallic silver image in the sound area of the film, converting only the silver sound image to metallic gold by treatment with a' gold toning solution, and subjecting the film to a series or exposure and color development steps to produce silver and dye images in the layers, th color development being one in which a color forming compound couples with the oxidation product of the developer and in which the gold sound image is not affected, and then removing the silver images formed in the various development steps without afiecting the gold or the-dye images.

2." The method of forming soundand natural color picture images in a film having a. plurality of layers sensitive to different spectral .regions Y on one sideof a'support which comprises form-' ing a metallic silver image in the sound area of the film, converting only the silver sound image .tometa-llicgold by treatment with a gold chloride solution; and subjectingthe film -to a series of 1 2,2 3,009 7 n. M g s 3. The method or formingsound and new color picture images in a film having a plurality,

of layers sensitive to difierent spectral regions on one side of a support which comprises forming a metallic silver image in the sound area of the film, converting only the silver sound image to metallic gold by treatment with a gold toning solution containing from 1% to 20% of gold chloride in waterand subjecting the film to a series of exposure and color development steps to produce silver and dye images in the layers; the color development being one in which a color forming compound couples with the oxidation product of the developer and in which the gold sound image is not affected, and then removing the silver images formed in the various develop-- ment steps without afiecting the gold or the dye images.

4. The method of forming sound and natural colorv picture images in a film having a. plurality of layers sensitive to different spectral regions on one side of a support which comprises forming a metallicsilver image in the sound area of the film, converting only the silver sound image to metallicgold by treatment with a gold toning solution, and subjecting the filmto a series of exposure and color development steps to produce silver 'and-dye images in the layers, the color exposure and color development steps to produce silver and dye images in the layers, the color development being one in which a color forming compound couples with the oxidation product of the developer and in which the gold sound -Jimage is not afiected, and then removing the development being one in which a color forming compound couples with the oxidation product of the developer and in which the gold sound image is not affected, and then removing the silver images formed in the various development steps without afiectingthegold or the 'dye images.

silver images formed in the various-development steps ina' weakly acid ferrocyanide bath withou aiifecting the gold or the dye images.

LEOPOLD D MANNES. LEOPOLD GO DOWSKY, JR.