US1928709A

US1928709A - Multicolor film and method

Info

Publication number: US1928709A
Application number: US425206A
Authority: US
Inventors: Leonard T Troland
Original assignee: Technicolor SA
Current assignee: Vantiva SA; Technicolor Inc
Priority date: 1930-02-01
Filing date: 1930-02-01
Publication date: 1933-10-03
Anticipated expiration: 1950-10-03
Also published as: GB370908A; DE557278C; FR709708A

Description

ct. 3, 1933. T TRQLAND 1,928,709

uUL'rIcoLoR FILI 'AND mamon Filed Feb. ,1., 1950 Patented Oct. 3, 1933 MULTICOLOR FILM AND METHOD Leonard T. Troland, Cambridge, Mass., assignor, by mesne assignments, to Technicolor, Inc., New York, N. Y., a corporationof Delaware Application February 1, '1930. Serial No. 425,206

11 Claims.

This invention relates to photographic films, and more particularly to films employed in the art of color photography.

It has been proposed before to produce color photographs by coating a base with an emulsion sensitive to a certain part of the spectrum, then to recoat this emulsion with a second layer sensitive to a different part of the spectrum, and so on if desired, then to expose the whole unit to the object to be photographed and subsequently to separate the emulsions for reproducing the image records. Various methods have been proposed for separating the emulsions, but none of them is quitesatisfactory in actual practice, or at least they involve more or less complicated operations and great care.

It is therefore the principal object of my present invention to provide a photographic lm with superimposed differentially sensitive emulsions of peculiar construction, which permits a relatively convenientseparatlon of the color records, and to provide a method of separating the color aspects recorded on this film, in a commercially feasible manner.

In order to facilitate the understanding of the following description, a few of the recurrent terms will bedefined. The term photographic film is employed to include generically all photographic records or recording articles or devices, whether the emulsion is supported upon celluloid or other supports or is self-supporting, and whether the film is adapted for either still or moving pictures. The term emulsio is used generically to connote either a true emulsion or any other composition which is sensitive to light.

The invention involves a film having several coatings of dierent sensitiveness to light, as for instance, described in my Reissue Patent No. 18,680, forcolor photography, of December 6, 40 1932, these coatings having in addition different characteristics lwith respect to their solubility. The layers may have different solubility either in one and the same solvent at different temperatures or in different solvents. vAfter the light sensitive strata have been simultaneously exposed, the layers are removed consecutively, with the exception of the layer immediately upon the base, by dissolving each layer in a solvent not affecting the remaining layers, and prints are made prior to each process of -removing one layer, and from the last.'layer, for vthe purpose of deriving from these prints correct reproductions of the various color aspects as originally recorded on the different strata of emulsion by known methods, of which examples will be given.

The invention will be explained by describing a simple, specific embodiment thereof by referring to the appended drawing, which shows a section through a iilm according to my invention.

B is the base of the film on which the iirst emulsion coating P is laid, which is sensitized to a particular color aspect as, for instance, with the aid of carbocyanol, (Eastman) to the red and blue rays, but not to green rays of the spectrum. first emulsion P comprises a hard gelatine which is insoluble or relatively insolublein water. This insolubility in water can be Aobtained by any Well known means, as, for instance, by treating the layer with chrome alum or with formalin, whereby great care must be taken to prevent any penetration of the hardening agent to adjacent layers, which can'be attained by using-the minimum amount of hardeningmaterial necessary to impart the desired degree of hardness to the para ticular kind of gelatine employed. A second 76 emulsion coating S is then applied over the first coating P, this second coating comprising an emulsion sensitized to a complementary color aspect, in this case, blue-green, by dyeing it with a suitable dye as, for instance, pinaflavol (I. G. F.) 80 This emulsion comprises gelatine readily soluble in warm water of about 80 or above degrees Fahrenheit. If desired, a coating of color F may be superposed on the ultimate layer. The lm prepared in this manner is nowl exposed in the` usual way, developed and a print made thereof which will preserve the composite picture contained in the emulsion. This print will be re- Y ferred to as composite positive. The negative is then subjected to the action of water of proper temperature, and the surface layer containing the blue-green color aspect to be referred to as green negative, is thereby removed. The layer comprising the hardened gelatine, to be referred to as red negative is now isolated and a print thereof can be made which will in this case contain the red color aspect and will be referred to as the red positive. Color prints can now be made by making an auxiliary or so-called dupe negative from the composite positive and combining it with the remaining layer of the original negative.

If the color separation thus obtained is inad-r equate, a method which I have described previously, for instance in my Reissue Patent No. 18,680, for color photography, of December 6, 1932, can be utilized for obtaining better results. This method comprises the following steps: A negative is made from the red positive, superimposed in registry upon the composite positive, and a print made therefrom. This will be a positive of the green negative which had been removed by dissolving its emulsion in warm water, the red aspect having been subtracted from the composite positive. A green negative? can now be made from this positive so that, together with the original red negative two regular negatives are now available which can be further utilized by any desired process.

From the foregoing it will be apparent to any one skilled in the art that my invention isnot limited to the embodiment above described, but that it can also be employed for `iilms containing more than two layers of differential color sensitiveness and with differentially soluble emulsions, that it is furthermore not conned to the use of water as etching means but that any solvent or combination of solvents which permit a differential etching of superimposed strata can be employed, and that is not essential whether the combination emulsion is exposed in the mannerv described or through .the lm, provided that the strata and filter coating have been arranged accordingly.

I claimz 1. In the art of making color photographs by recording different color aspects on diierent superimposedparts of a light sensitive emulsion, the method of separating said color aspects, which method comprises the simultaneous recording of different color aspects on said different parts of the emulsion, in copying the combined records, in subsequently separating said parts by consecutive differential dissolving, and in making prints of the records remaining after each dissolving operation. y

2. In the art of making color photographs by recording different color aspects on two superimposed parts of a light sensitive emulsion, the method of separating said aspects, said method comprising the simultaneous recording of two color aspects upon said two light sensitive parts of said emulsion, and in separating the two parts by copying the combined aspects, dissolving the outer part, copying the remainder and combining the copy of the combined aspects with that of the remainder for obtaining a copy of the aspect upon said dissolved part.

3. The method of making color photographs, which method comprises simultaneous printing of two color aspects upon two layers of emulsion, one layer being insoluble and the/other soluble in hot water, in developing the composite image record, in making a positive of the combined record, in dissolving the outer layer in hot water, in superimposing the remaining layer upon the positive of the composite record, and in making a print from the superimposed records.

4. A lm for making color photographs by recording different color aspects on different layers of the emulsion of the illm, characterized in that the diterent layers have a different color sensitiveness and different solubility in hot water, the solubility increasing from the innermost towards the outer layer.

5. A photographic lm having a base and an emulsion comprising a plurality of layers sensitive to different parts of the spectrum and of different solubility in a certain solvent of varying temperature, the solubility of said layers in said solvent increasing from the layer next to the base toward the outermost layer with steadily varying temperatures of said solvent.

6. A photographic film comprising a base and emulsion upon said base, said emulsion being sensitive to a certain range of the spectrum and substantially insoluble in hot water, and a second emulsion upon said first emulsion, said second emulsion being sensitive to a diierent range of the spectrum and substantially soluble in hot water. v

7. Av photographic lm having an emulsion comprising layers of different sensitivity to spectral colors and of correspondingly different solubility in a certain solvent, the solubility increasing from the innermost towards the outermost layer.

8. A photographic lm comprising silver halide emulsion layers of different sensitiveness to spectral colors, each layer being soluble in a diierent solvent.

9. A photographic nlm comprising a baseand an emulsion consisting of a plurality of layers sensitive to different parts of the spectrum and of diierent solubility in water of different temperature, the solubility in water increasing from the layer next to the base toward the outermost layer.

10. A lm for making color photographs by recording different color aspects on diierent layers of the silver halide emulsion of the lm, characterized in that each layer has color sensivity and solubility characteristics substantially diierent from the corresponding properties of the other layers.

11. A photographic lm having a base and a silver halide emulsion comprising two layers with different solubility ina certain solvent as well as different color sensitivity.

LEONARD T. TROLAND.