US1956122A - Method of producing multicolor photographic reproductions and cinematograph films - Google Patents

Description

Aprll 24, 1934.

METHOD OF PRODUCING MULTICOLOR PHOTOGRAPHIC BEPRODUCTIONS AND CINEMATOGRAPH FILMS Filed Dec. 1929 BED AND BLUE OBJECT EXPOSED Silver halide sensitive to blue and green Silver halide sensitive to red.

Backing DEVELOPED AID FIXED Metallic silver image uncolored Metallic silver image uncolored Backing MORDANTED Mordanted. silver unc olored Mordanted s i 1 ver unc o1 cred Backing BOTH LAYERS DYED BLUE Blue image Blue image Backing ONE IMAGE DEfiOIORIZED Mordanted. silver salt unc olored Blue i'mage Bac king THE UPPER IMAGE COLORED BED Red image Blue image Backing INVENTOR. l5. Gaspar BYIWM A TTORNEYS.

Patented Apr. 24, 1934 METHOD OF PRODUCING MULTICOLOR PHOTOGRAPHIC REPRODUCTIONS AND CINEMATOGRAPH FILMS Bla Gaspar, Temesvar, Rumania Application December 16, 1929, Serial No. 414,563 In Germany September 24, 1929 7 Claims.

This invention relates to the production of two .or' more color photographic reproductions and cinematograph films based on the substractive process, and enables a plurality of part pictures 'to be produced by one exposure, also undivided additional treatment to be performed for the production of differently colored part pictures in one layer.

This is accomplished in the following manner: A-layer is formed by the consecutive application of several part layers, which in the known manner are made sensitive to different zones of the spectrum, preferably silver bromide emulsions, these layers, after the same have dried on the carrier, constituting an intimately coherent whole.

This composite layer is exposed in a camera or copying device and subsequently developed. When the image has been formed by the action of different-colored rays of light blackened portions will result only in the particular part layers which are made sensitive to the corresponding rays. In this manner different black and white part pictures are obtained, which are superimposed in different strata of the layer.

These silver pictures are converted into 'a mordant compound or the like, which is adapted to receive or retain colors. The superimposed part pictures converted into a mordant compound are at first colored with one particular color. If, for example, red is employed, all superimposed part pictures will assume the red hue. After the usual washing process up to clarification drying is effected and the part picture which is situated on the surface decolored, the .decolored part layer then being recolored in a different hue, for example yellow.

This decoloring and recoloring process may be performed in different manners. The color is either converted into an uncoldired compound and simultaneously dissolved out, or the same is destroyed by oxidizing or reducing agents without the mordant compound being attacked or dissolved by this treatment. The mordant remaining in the layer is again colored with a different color. The recoloration of the decolored or colorless mordant may also be so performed that the mordant is converted into a colored compound. The coloring matter contained in the part layer to be decolored or recolored may also be subjected to a chemical treatment in which the color itself is converted into a different-colored chemical compound or into another color respectively.

For this purpose preferably rapidly acting chemicalreactions are made use of, in such manner that the desired effect in the outer or uppermost part layer, which is subjected to the immediate action of the liquid, has already taken place before the reactionby reason of gradually occurring diffusion-has had an opportunity of becoming effective on the underneath strata. 6( These reactions are then brought to a standstill by rapidly washing out the reagent, or by suitable interruption baths, after the desired decoloration, coloration or recoloration has been attained.

To enable the reaction processes to be controlled, for example as regards the extent of the coloration and prevention of the decoloration or recoloration from advancing to the deeper layers, control marks are employed. These are situated at the edge of the pictures or copies, or in the case of cinematograph films at the edge between the perforations. These markings are produced by exposure to colours of the single spectral zones, for example red, green or blue, through the medium of filters or colored rays of light, in such manner that selectively as desired blackened portions are formed only in the single part layers which are made sensitive to the particular rays of light.

The thin, superimposed and intimately united part layers form a composite layer of approximately the thickness of the'emulsion to be found on a plate of the usual kind, and do not offer any obstruction to the penetration of the developer. Between the single part layers it is also possible to provide thin films of gelatine or the like void of silver bromide and pervious to water.

The part layers are developed, and since these are sensitized in different manners different superimposed part pictures result which are then colored in conformity with their color sensitiveness.

As an initial step all superimposed part pictures in the layer are colored with the one color. Following this one of the part layers is decolored and thereupon recolored in another color. This recoloration applies to the outer layer, i. e., that situated on the surface. For this purpose certain advantage will be found to exist in forming the composite layer from part layers of different thickness which, irrespective of the thickness of the single layers, each contain the same or approximately the same amount of silver, the layers differing in their percentageof gelatine. It will furthermore be found desirable to make the outer layer, i. e., that situated on the surface, and the undermost layers, i. e., those situated adjacent the carrier, extremely thin in relation to the intermediate layer. This is of importance in order to make the diffusion distance which the reagents 1' and colors require to traverse for decoloration and recoloration of the uppermost layer short in relation to the distance which the same would have to traverse in penetrating the deepest part layer, so that if, for example, the outer layer is 2/ 1000 mm. thick and the underneath layer possesses a thickness of 2/100 mm., the proportion of the two diffusion distances will be 1:10. In other words, if the decoloration process extends to twice the depth than may be necessary for the purpose of decoloring the outer layer, merely a tenth part of the under layer will also undergo decoloration, this having only a negligible effect on the depth of the tone.

The decoloration and recoloration may also be performed by diazotization and subsequent coupling with an azo-component. Thus, for example, two layers may be colored with fuchsin, treated with nitrous acid, which decolors the fuchsin in the outer layer, and couplingperformed with resorcin. In this manner a yellow part picture suitable for substractive color photography is obtained in the part layer thus treated.

The single figure of the drawing is a fiow sheet which sets forth the steps of the method.

It is also possible to obtain three different colorpictures in one layer, this method being particularly adapted for reproductions on paper. A transfer layer is employed, which consists of three part layers made sensitive to different colors. As an initial step this layer is colored as a whole, then the uppermost part layer recolored, and the composite layer removed and transferred to a fresh carrier, so that theunder layer is then situated on top and is also subjected to decoloration, recoloration, etc.

The recoloration of the part layer may also be performed by etching agents or by other chemical action adapted to vary the original color. Thus, for example, safranin-azo dyes, such as Janus blue, may be employed which, after treatment with muriate of tin (SnClz) provide-a red color.

Azo-dyes or other suitable color compounds may be employed, which upon the decoloration are converted into colorless bodies; or split products may be used which remain in the layer and form the basic material for forming a fresh dye body.

In the same manner recoloration of the decolored mordant may be efiected without a dye if the mordant employed is a ferrocyanide which, after the decoloration or simultaneously therewith, is converted into a colored ferrocyanide, for example Prussian blue. Or it is also possible to employ as mordant a colorless metallic salt, which after the decoloration is converted into a colored metallic salt, for example lead ferrocyanide converted into lead chromate. Or alternatively, both methods may be combined. A. composite layer is employed consisting, for example, of three part layers, and after the exposure, developing, etc., the silver image is converted into ferrocyariate of lead and dyed with a suitable dye, for example rhodammin S. The uppermost layer, which containsthe yellow part picture,.is decolored with an alkalic sodium sulphite solution and converted with potassium chromate into yellow lead chromate.

The whole layer is subsequently removed and applied to a fresh carrier, so that the uppermost layer first treated then comes to lie at the bottom,

and the part layer which was originally the undermost one is situated at the top. The same is then decolored in similar manner, and con-' verted with a ferric salt into Prussian blue. Other metallic salts providing suitable color combinations may also be employed.

, In a modified form of embodiment the coloration may be performed simply on the surface, in which method a tanning of the gelatine image is accomplished by the use of suitablemordants and a relief picture thus obtained on the surface, this relief, after effected decoloration of the outer layer, being colored on the surface with utilization of the known properties associated with reliefs which, in accordance with the extent of swelling, possess a varying absorptive power for fatty dyes.

The .mordant formation may, if desired, be. so

performed that, in addition to the mordant, a

silver compound, for example, silverbromide, capable of being redeveloped results, this silver bromide after effected decoloration of the outer part layer being developed in the surface layer and toned in a tone bath of the usual kind.

The dye to be decolored in the outer layers may, if desired, be added to the emulsion. It is continued action on the-part of the latter, which is still contained in the layer, is interrupted by a bath containing a suitable oxidizing agent. Beyond this additional penetration of the reagents or dyes employed for decoloring or recoloring the outer part layer may be decelerated or prevented by hardening the layer, after the same has been colored, by the use of formalin, alum or the like, in such manner that the layers lose to a great extent their capability of swelling.

The method according to the present invention may also be employed in conjunction with cinematograph films, preferably in such cases in which the oneside of the film is coated with a simple layer of emulsion and the other side with a composite layer, i. e one composed of two part layers. J

It will be sometimes found preferable in carrying the invention into practice to provide nuances of the dyes, which are yaried in chemical manner, by the addition of other dyes, and for this purpose dyes may be employed which are conjointly decolored or varied or which also maintain their color in the decolored layer. For treating the outer part layer a dye may also-be employed which is used simultaneously with the decoloring-agent and is not afiected by the same.

A further important feature is that the finished picture, in which the superimposed part layers are difierently colored, has these part layers so toned in relation to each other that a natural color reproduction isobtained. For this purpose solu tions or reagents are employed which act only on the one part picture. If, for example, there is situated above a fuchsin picture a ferric (blue) one, the-latter may be weakened by a diluted oxalic acid solution, while the fuchsin picture may be weakened with a diluted alcoholic muriatic acid solution, which does not attack the blue.

. The chemical substances necessary for the double-sided treatment of films may be applied in the form of solutions which contain a thickening agent. In this manner these liquids do not dry so rapidly, and may be employed in the thickness necessary to be effective, also allowing a double-sided coloring or recoloring of the film in simple manner. The solutions are rinsed off by a strong spray or in other suitable manner.

The necessary filter colors or sensitizing agents, or both'of these, may be incorporated in the base, or applied to the carrier respectively, with subsequent application of the emulsion.

For developing purposes slowly acting developers are employed which also exert favorable action as regards the depth of the image. In some cases it will be found preferable to incorporate a developing substance in the base or carrier.

Obviously the reactions in question may also be performed in separate layers, or on the front and rear sides of a film respectively.

If a filter color is incorporated in the emulsion, the concentration and the thickness of the layer may be such that the screen effect of the filter color only commences in the depth of the layer. It is thus possible, for example, that when using a yellow dye blue rays may be allowed to act on the upper or outer part of the layer, so that in this manner a layer is obtained having two part images.

In producing copies, and more particularly if merely a small number of copies are required, it will be found of advantage to employ as negative in place of substractive multi-layer images transparent pictures of the multi-color screen type. For this purpose, according to the present invention, regular multi-color screen images are employed, the filter elements of which, however, are so colored, that the same possess filter colors rectified for substractive purposes, and therefore differ from the usual coloring of those screens employed for observation and reproduction by their transparency. These screens should not be connected with the emulsion, and the plate or film sensitive to light is exposed in contact with the screen, thereafter taken apart, the plate or the film developed, etc., and in a suitable apparatus (copying frame or the like) brought into alignment for copying on to the composite layers described above.

In this manner one screen will be found to be suificient, and this may be employed for producing a number of exposures or copies.

Obviously the various reactions referred to may under circumstances also be employed inother sequence. Thus, for example, the mordant might be converted into a difierently colored salt, and the outer part layer not decolored until afterwards.

It will be understood that no restriction is made to the specific forms referred to, and that various modifications are possible within the meaning of the above and the annexed claims without departing from the spirit of the invention.

What I claim as new and desire to secure by Letters Patent is:

1. A method of producing a plurality of color photographs and cinematographic films which consists in coating one side of a support with a plurality of differently sensitized emulsion layers, exposing in order to produce a part image in each layer, developing and fixing said images, coloring all of the images with a single color, decolorizing the outer part image and recoloring said outer image with another color.

2. A method of producing a plurality of color photographs and cinematographic films which consists in coating a support with a thick emulsion layer sensitive to one region of the spectrum, coating a thin layer of emulsion sensitive to a different region of the spectrum on the thick layer, exposing in order to produce a part image in each layer, developing and fixing said images, coloring all of the images with a single color, decolorizing the outer part image and recoloring said outer image with another color.

3. A method of producing a plurality of color photographs and cinematographic films which consists in coating one side of a support with a plurality of differently sensitized emulsion layers, exposing in order to produce a part image in'each layer, developing and fixing said images, coloring all of the images with an azo-dye, decolorizing the outer image by diazotization with nitrous acid, and recoloring the outer image by coupling the azo compound image with another dye.

4. A method of producing a plurality of color photographs and cinematographic films which consists in coating one side of a support with a plurality of differently sensitized emulsion layers, exposing in order to produce a part image in each layer, developing and fixing said images, coloring all of the images with fuchsin, decolorizing the outer image with nitrous acid, and recoloring the outer image by coupling the image with another dye.

5. A method of producing a plurality of color photographs and cinematographic films which consists in coating one side of a support with a plurality of differently sensitized emulsion layers, exposing in order to produce a part image in each 115 layer, developing and fixing said images, coloring all of the images with fuchsin, decolorizing the outer image with nitrous acid, and recoloring the outer image by coupling the diazotizable dyestuif image with resorcin.

6. A method of producing a plurality of color photographs and cinematographic films which consists in coating a support with a thick emulsion layer sensitive to one region of the spectrum, coating a thin layer of emulsion sensitive to a different region of the spectrum on the thick layer, exposing in order to produce a part image in each layer, developing and fixing said images, coloring all of the images with an azo-dye,- decolorizing the outer image by diazotization with nitrous acid, and recoloring the outer image by coupling the azo compound image with another dye.

'7. A method of producing a plurality of color photographs and cinematographic films which 5 consists in coating one side of a support with a plurality of differently sensitized emulsion layers, exposing in order to produce a part image'in each layer, developing and fixing said images, coloring all of the images with fuchsin, decolorizing the outer image with nitrous acid and recoloring said outer image by coupling the image with resorcin.

BELA GAsPAR.

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