DE965614C - Process for making multicolor photographic images - Google Patents

Description

ISSUED JUNE 13, 1957

C ρ 102 IVa / 57 b

Color photographic recording and copying materials usually consist of a carrier on which two or more for different spectral regions sensitive silver halide emulsions are poured in layers. Since the manufacture multi-layered material is difficult and expensive, there has been no lack of attempts to achieve this Reduce the number of layers required. There are tons of suggestions in this direction, such as B. the multiple exposure and resensitization of a layer, the use of Mixed grain emulsions or the division of a layer into superimposed zones,

The division of a layer into zones (»stratification«) through damping dyes, superficial Raising awareness or in some other way (see J. Friedman, History of Colorphotography, Boston 1947, p. 96 ff.) Is easier to accomplish than pouring multiple layers, and in particular one can find very thin zones by stratification rather than by pouring over one another Get layers. Despite this possibility of subdividing layers into very thin and It is uniform zones according to the previous methods difficult to get well differentiated dye images in

709 534/163

of a zone. Most of the processes separate the zone patterns by specific ones Developer, fixing baths or toner without getting correct partial images. It is an object of the present invention to have two color images in two adjacent rooms of a photographic material, it is irrelevant whether these spaces through Stratification, by pouring ίο layers on top of each other or by mixing emulsions have arisen. Other aspects of the invention will be made clear as the description proceeds will.

It has now been found that multicolor images can be obtained using those known per se Method can produce, after which Silberbilde.r with existing in their immediate vicinity reducible Dyes or dye components under the action of a silver bleach bath up to Oxidation of the silver image can be reacted when a photographic material is used containing at least two different types of silver images, e.g. B. different partial color separations of a multicolored original and in which not all silver images of one Oxidizing agents (e.g. reducible dyes or dye components) are surrounded by that one A silver bleach bath can act on this material, which is surrounded by the oxidizing agent The silver image is completely or partially oxidized and that what is possibly still present here can be found Remaining silver as well as the silver of the other partial pictures converted to dye images by any method.

The new method is based on the observation that a silver picture: to an iti water or in a fixer, soluble silver picture can be oxidized, while at the same time the necessary for this Oxidizing agent is used to produce a color image, and that this reaction only then runs smoothly when the oxidizing agent is in direct contact with the silver. Suitable oxidizing agents are reducible Dyes and dye-forming substances such as. B. vat dyes, azo dyes, diazo compounds and aromatic nitro compounds.

In particular, it was previously unknown that only that silver which is in direct contact is used up in the destruction of the color is with the dye and that therefore the effect of a bleaching bath is through the presence of dyes or dye-forming substances on one of several rooms (under simultaneous Creation of a color image in this one space) can be restricted.

If there is a silver image in each of two adjacent spaces A and B of a photographic material and if only space A is brought into direct contact with an oxidizing agent and if the material is in a suitable medium (e.g. in the case of azo dyes in a solution is bathed by hydrogen bromide and thiourea) ¹ , the metallic silver of space A is oxidized to a simple or complex silver salt and thus converted into soluble form, resulting in a dye image corresponding to the silver image in A (in the case of azo dye, an inverted dye image), and the silver image in B is not or hardly changed. The silver image in B can then be converted to a positive or negative dye image by any of many methods; it can e.g. B. in a stain picture or a toned picture or by chromogenic development in an indophenol or azine or azo picture. The two silver images in A and B can have the same or different optical density and gradation.

The complete consumption of the silver in room A has the particular advantage that with this method of working one gets by with minimal amounts of silver for conversion into strong color images of good graduation and that, after this conversion, the image in A does not have a disruptive effect on the conversion of the image can exercise in B.

The preferred embodiment of the new process consists in that the said spaces A and B are zones of a single layer, that an azo dye is used as the oxidizing agent in zone A , from which a color image is inversely proportional to the density values of the silver image in A and that the silver image in zone B is converted to a proportional color image. If a nitro compound is used as the oxidizing agent (Friedman, History of Colorphotography, p. 419), a color image proportional to the silver image is obtained in room A.

It is unimportant for the method described in more detail below whether the said oxidizing agent is already present in the photographic material before exposure (e.g. an azo dye, which initially serves as a damping dye and then as an image dye) or whether it is only after the exposure is incorporated into the material. Likewise, it is not crucial whether or not that is mentioned proportional color image is made up of diffusing or non-diffusing components, which are added to the material before or after exposure.

The halogen silver, which was not consumed during the development of the silver images, can be removed by fixation at any time before, during or after the oxidation of the silver in A. In general, it is advisable to fix the silver in A before oxidation. However, it is also possible to leave the halogen silver in the film in order to use it later to produce a third color image. A further modification of the process consists in the fact that after a silver image in B and a silver-free color image in A have been produced, the silver image in B can be weakened or intensified by known methods, whereby the color image in A is not influenced.

The method described here is suitable for reproducing any images that z. B. a picture with associated mask, a pair of nested stereo recordings, a two-color image or also partial color images of a three-color image such as B. Front images of a bipack «can be. It is also possible to use the procedure in various ways in combination with others Method to use to get three-color pictures

ίο ". For example, it is possible on one side a transparent film «two zones or emulsions according to this invention and on the apply another photosensitive layer on the same side or the reverse side of the film.

The person skilled in the art can easily identify those combinations among the many possible combinations find out in which the specified method for the reproduction of two partial color images suitable, while a third is generated in a different way.

This working method is suitable for recording and copying processes, for materials on transparent or reflective backing, for cinema films and still pictures. When the procedure is used to make copies, the two latent over images can be exposed by exposure simultaneously (e.g. with white light) or one after the other (e.g. with monochromatic lights) will.

example 1

A film sensitive to blue and green light (e.g. Agfa Isopan) will do 1 minute in one 0.5% tartrazine solution bathed and dried.

A step wedge with blue light (Wratten No. 34) and a step wedge with yellow light (Wratten No. 16) are copied from the layer side, the film is developed with metolhydroquinone, fixed, washed thoroughly to remove the tartrazine and in formaldehyde hardened. ¹ it is then dyed for 1 minute at 50 ° C in an i ° / o solution of the dye according to blaustiehiggrünen Swiss Patent 150,308 and nachgebadet in a solution of hydrochloric acid 2-Naphthylbiguanid order to precipitate the dye.

In the cross-section it can then be demonstrated that the image generated with blue light and predominantly also the dye are localized in the surface, while the behind produced yellow filter Picture fulfilled the whole shift. The film is then in a solution of the following composition bathed:

Sodium chloride 50 g

Hydrochloric acid, concentrated 80 ecm

Thiourea 4g

2-Oxy-3 - aminophenazm 10 mg

2,3-Dimethylquinoxaline 30 mg

Water, fill up to 1 1

The film is removed from the bath as soon as a field appears free of dye and silver. The silver image created behind the blue filter is (with the exception of the overexposed Region, d. H. where there was more silver than was needed to completely destroy the dye) disappeared, while the silver image created behind the yellow filter is somewhat weakened still exists. At the same time there is a steeply graduated one that is reversed in the density values Dye image of the blue filter extract. ·. and only a very flat inverted dye image of the yellow filter image generated. The silver image created behind the yellow filter is then colored through development converted to a color image.

Example 2

The procedure is as in the previous example, but the exposures are made through the substrate executed. In this case the dye with the depth image created behind the yellow filter has more direct contact than with the surface image created behind the blue filter Silver of the picture created behind the yellow filter dissolved more strongly in the dye bleach bath than the silver of the rear blue separation image, and accordingly the dye image is also of the yellow exposure Graduated much more steeply than the color image of the blue exposure created in the dye bleach bath, which the latter is only transformed into a strong color image through colored development. go

These examples show that between one surface image and one the entire layer thickness occupying depth image can be differentiated by dye destruction. In one shift a thickness of about 30 μ can be obtained using this method arrive at a very sharp color separation. On the other hand, this procedure is sufficient in one Layer of only small thickness only for the separation of images with a small tonal range, e.g. B. to Reproduction of two-tone line drawings. The separation of Surface and depth images can be useful due to color destruction, because, as can be seen below an inadequate separation of the two images can even be an advantage.

The conversion of only one of the two silver images effected in the first two examples into a color image, and the second silver image is preserved for later conversion to a different color image, can be made even more specific if one considers the reaction conditions amends. You can z. B. take advantage of the fact that there are all possible There are transitions between such dyes which (like tartrazine) with the greatest of ease stain the layer in its full depth, and those dyes which (such as those in the USA patent Reissue 23 357 dyes described) only stain a thin superficial zone, especially if the film material contains a basic precipitant (see Friedman, op. cit., p. 421). The depth of the staining is in all these cases of concentration, hydrogen ion concentration and temperature of the dye bath. Some dyes have been observed to have a greater affinity for the casting than for the light-sensitive

seem to have sensitive shift. So you get. z. B. when coloring a "Du Pont Release Posdtive" film .from an alkaline solution with the yellow dye of the formula

COOH

CO:

, NH

'NH

N = N

N = N

SO ₃ H

a more complete reaction with a deep-seated one than with a superficial silver image. You can also use diffuse instead of dyes to stain, stain image-wise in an acidic thiourea-containing bath (British patent

»Ο 553 352) and by adding salt or organic solvent regulate the penetration depth. If you swam to the color lead bath. before adding oxidizing agents not involved in the composition of the image (British patent 539 190), so obtained

as one flatter color images and a more complete one Oxidation of silver. If so, these - oxidizers Diffuse only with difficulty, so their effect on the surface is limited. Furthermore has one by choice and concentration of the catalyst (hydrogen carrier) the possibility of the To regulate the layer depth in which silver is able to react with dye. If you z. B. If the quinoxaline concentration is reduced in the first example, a better differentiation is obtained of the pictures. On the other hand, if a catalyst is used that is difficult to penetrate into the If the layer diffuses, this promotes the limitation of the color image and the destruction of silver on the surface of the layer. This can be achieved e.g. B. by briefly bathing in an alkaline Solution of sulfonated 3,3-carbonyl-bis a-hydroxy-S-aminoptienazine (British patent 522 611). After all, at the time of casting, the dye is evenly poured into the material to be stratified Layer, in an inactinic base, in an inactinic protective layer, in one of two light-sensitive layers or in one of two emulsions to be mixed, so

_ This results in a myriad of variations.

These methods of partial staining are off well known in the literature, and their sensible application can largely regulate to what extent the silver image of only one room or both silver images react with the dye!

As can be seen from the following example, a better separation is obtained if the the two silver images do not penetrate each other, but rather lie in separate rooms.

- Example 3

The procedure is as in the first example, but only exposure to blue filters occurs one from the layer side and one through the substrate. It becomes through it reached an almost complete separation. The silver of the image, which from the layer side is copied is completely eliminated, while the silver of the image copied through the substrate is hardly affected. Only in the silver areas of the layer-side image is the dye destroys.

After the dye has been destroyed, it is briefly bathed in a sodium thiosulphate solution in order to eliminate it of oxidized silver to complete. The image is then rehalogenized in an acidic copper bromide bath and in the following Bathroom developed:

p-Diethylaminoaniiline sulfate 2 g

Sodium sulfite, anhydrous

Soda, anhydrous 50 g

Water 1000 ecm

i-phenyl-3-methyl-5-pyrazolone .. 2 g

Alcohol.: 20 ecm

After oxidation of the silver in a bath of potassium ferricyanide and potassium bromide uii.d removal of the silver salts in a neutral fixer a pure dye image is obtained, namely the image copied from the layer side as a blue positive go and that through the. Base copied image as a purple negative.

Example 4

A blue-sensitive film (e.g., B. Du-Pont-Positive release Fdlm) is '' long bathed at 18 ⁰ C for 4 minute in a solution consisting of 127 parts of 8o% alcohol and 1 part · a o, oo5 ° / oigen alcoholic solution of 5- (2-ethyl-1-benzothiazylidene-ethylidene) -3-n-hexylrhodamine is prepared. After brief drying in air, the film is bathed at 18 ° C for 5 minutes in an aqueous solution which contains 50 g of tartrazine and 0.04 g of condensation product of 1 mole of p-octylphenol and about 8 moles of ethylene oxide per liter. Then it is pressed between filter paper and dried.

The film treated in this way is filtered from the back through a step wedge with a blue filter (Wratten No. 47) and exposed through a step wedge with a yellow filter (Wratten No. 16). then is treated with a metolhydroquinone developer (e.g. Kodak DK-50), fixed and washed. For superficial coloring: the film is bathed for 8 minutes at 18 ° C in the following solution:

Blue-green dye according to Swiss patent specification 150 308, i%

Solution 50 ecm

Sulfuric acid, 2n '5 ecm

Condensation product of 1 mole of p-octyl ^lao

phenol and about 8 moles of ethylene oxide, 0.12% solution 5 ecm

This dye was precipitated by bathing the film in a solution of 2-naphthylbiguanidehlorhydrat wind the dye 9 minutes

long at 18 ° C in the places where superficial Silver is present, destroyed in the following bath:

Sodium chloride 5o, og

Hydrochloric acid, concentrated 8o, o ecm

Thiourea 4.0 g

2-Oxy-3-aminophenaz4n 2.5 'mg

Water to 1.0 1

The remaining silver is rehalogenized as described, in a chromogenic developer re-developed with acetoacetarnilide and removed from the film. That through yellow filters The copied image is obtained as a blue positive and the image copied through the blue filter is obtained as a yellow negative.

Example 5

From the present example dst in combination

ao hang with Fig. 1, α to g, it can be seen how an image in natural colors can be obtained by repeating the method described above. In Fig. 1, the layers are shown in cross-section during the various stages of imaging. Therein, black areas mean metallic silver or a neutral gray color, the dotted areas a blue color and the hatched areas a yellow color. In Fig. 1, α represents the original to be copied, b the photographic material to be used, c is the silver image primarily obtained, d the color image obtained therefrom: e is a silver image obtained by copying d and / that in turn obtained therefrom Color image. Finally, the visual impression made by the color image / is reproduced with g.

A blue-sensitive film is colored yellow with a diffusely destructible dye and the surface is sensitized to long-wave light (b). A step wedge is copied through the dta blue, a yellow and without filter (α) through the layer support onto the film. After development, a composite silver image: c is obtained. This wind with a blue. Azo dye stained on the surface, the dye on the. Silver areas destroyed, the remaining silver rehalogenized and treated with a yellow chromogenic developer. After all silver has been removed, em color image d is obtained.

This picture is now used as a master copy and copied with white light onto a layer identical to b. In this case, a silver image e is obtained, which is in the described manner · converted to a dye image /. This image appears when viewed through as an image g identical to the photographed object α.

Example 6

Proceed as ¹ in the last example to create the positive-negative color image; (Fig. 1, d) to generate. From this, extracts are made through yellow filters and blue filters, one on ordinary panchromatic film, the other on reversal film. These two partial images can be used to produce color-correct copies according to the most varied of known processes.

If a stratified film of soft gradation is used to produce the master copy d , partial images can be obtained according to this method, the H and D curves of which are characterized by a long straight slope.

In order to obtain copies of the correct color using the method explained in Examples 5 and 6, it is important that the positive-negative color image (FIG. 1, d) is reproduced correctly. The use of a yellow and a blue dye, the absorption areas of which do not overlap, is essential for such perfect reproduction. However, this condition cannot be met with the dyes available. It is known that this inevitable error can be remedied by color masking. From Fig. 2, the possible "errors" can be seen, through which the color image (Fig. 1, d) can be "falsified":

1. The 'two silver ¹ images (Fig. 1, c) can extend too deep into the layer, so that consolidation occurs in the central zone. This effect is particularly caused in developers that are rich in silver solvents, or by too deep sensitization of the film, which contains only an insufficient amount of damping dye. From such mixed silver images (Fig. 2, a) is the positive-negative color image (Fig. 2, b) is obtained. But this is a double masked image in which both the yellow and the blue dye image are masked; therefore the color image (Fig. 2, b) provides correct partial images.

2. Due to insufficient color destruction of the blue-colored picture (Fig. 1, c) , unused silver remains in the surface, which is then developed in color as residual silver. Instead of a color image (Fig. 1, d) a color image (Fig. 2, c ) is then created, which consists of an unmasked yellow and a masked blue image.

3. The color destruction is driven too far, which then finally results in a color image (Fig. 2, d) . In this, the blue color image is unmasked, while the yellow image is masked.

It can be seen from what has been said how, by changing the working conditions, a color image (Fig. 2, b, c or d) can be obtained which is masked in a similar way to the pictures produced according to British patent 516 816 and of which then corrected partial images can be produced. On the one hand, the method can be modified for almost any dye pair, on the other hand, one can select a dye pair with a suitable overlap of the absorption curves and copiers of suitable wavelengths in order to adapt the optical conditions to the method. When using the method for the production of master copies, the procedure is generally such that masked images are obtained while in the

709 534/163

Production of positive images (Fig. I, /) masking to avoid addiction.

Since a veil of color does not interfere with the use of pictures as master copies, S recommends, in these cases, to color the silver pictures (Fig. I, c) vigorously in order to deposit at least as much dye as the maximum amount of silver in the areas Blackening in the layer to be colored is equivalent. This gives color images with flat, straight-line gradation.

The relationships are actually somewhat more complicated than they are described above and shown schematically in FIG. It is Z. B. demonstrable that the degree of mixing of the silver images in the central zone (Fig. 2, a) increases with increasing silver density and that then a color image (Fig. 2, b) is formed in which the blue and the yellow mask in different ways deviate from the proportionality. The information given therefore only allows qualitative predictions about the mutual influence of the images. The effects described above and referred to as "errors" make the new process a very useful aid for generating color-correct images. This method of mutual masking is not restricted to the zones of a single layer, but is just as suitable for differentiating silver images in adjacent layers cast one on top of the other or in layers with mixed grain emulsions.

Example 7

An orthochromatic plate is used to create a two-color image in natural colors Sensitized on the surface for red light and in the entire depth of the layer with an in the developer stained fissile light red dye. The plate w'kd in a camera from the glass side exposed (through an upstream filter, which emits ultraviolet and short-wave blue rays absorbed), developed, fixed, superficially blue, stained, the dye on the silver spots destroyed and the remaining metallic silver according to the process described in patent 932,345 developed into a yellow image.

The two-color image thus obtained is copied with white light on a paper, the one blue-sensitive emulsion that bears before pouring with a water-soluble, easily washable yellow dye and subsequently through the paper backing with an alcohol-soluble one and not deeply penetrating red sensitizer is stained. After developing, fixing and superficial coloring with a blue-green azo dye, the azo dye is destroyed image-wise and the remaining silver developed into a yellow-red dye image.

Example 8

It becomes a film for making a three color negative poured, the -on the support in the usual way with a red-sensitive layer Blue-green coupler, over it a green-sensitive layer with purple coupler, over it a yellow one Contains filter layer and on top a blue-sensitive layer with a gel coupler. In the red-sensitive Layer there is also a red azo dye and in the green sensitive Layer of a yellow azo dye; their concentrations are chosen so that they just lead to education Sufficiently strong colored masks are sufficient.

After exposure, the material is treated with a metolhydroquinone developer. Here Care is taken to ensure that - over the necessary for later color development Amount of silver - additional silver is developed in the two lower layers, i.e. silver images of excessive steepness are produced in such a way that at the blackest points per equivalent of azo dye there are 4 more atoms of silver than for dye formation colored development are needed. Then it is fixed and treated in a dye destruction bath Shallowly graduated positive azo images generated in the lower layers. At the same time will this treatment removes the additionally developed silver from the lower layers, while the silver reserved for color development is not adversely affected. In the end wind the remaining silver rehalogenized, treated with a coloring developer and finally removing all silver from the film in the usual manner.

A color negative is obtained which has masks corresponding to the blue-green and purple images having.

Similar results are obtained when over the green-sensitive layer free of azo dye a filter layer is cast, which is a yellow azo dye and in very low concentration contains a green-sensitive silver halide emulsion, while the other layers in that described Way are poured.

Example 9

A green-sensitized silver halide emulsion in polyvinyl acetate is dispersed in gelatin, which also contains a red-sensitized silver halide emulsion, and poured onto a support. After exposure, development and fixation, the material is bathed in an aqueous solution of an azo dye, whereby only the gelatin, but not the polyvinyl acetate, is colored ¹ . In a dye-destroying bath, therefore, only the silver image suspended in the gelatin is dissolved and at the same time transformed into an inverted color image, while the silver image distributed in polyvinyl acetate remains unchanged and in the same. As in the previous examples, it is converted into a FaA image by chromogenic development.

Example 10

A technical drawing is displayed on a yellow background with black, white and blue ink manufactured. This drawing is made on 35mm film

photographed which, like the film in Example 4, was pretreated and inserted into the camera with the layer support facing the objective. The further treatment is also carried out as in Example 4.

An image is obtained that is suitable for classification in a micro-card index is suitable. In the projection, the background appears colorless, and in the Original black, white and blue elements are reproduced in the image in blue, yellow and green. Intermediate tones are also reproduced well. The sharpness is particularly noticeable, with which the finest details are reproduced. The same principle applies to the technical Drawing contact copies made in large format. These exhibit the same favorable Properties up and can be manufactured at a price not very much above that an ordinary solid color copy on silver halide paper.

Claims (7)

PATENT CLAIMS: i. Process for producing multicolor images using those known per se Method according to which silver images with reducible ones present in their immediate vicinity Dyes or dye components under the action of a silver bleach bath up to to oxidize the silver image, characterized in that a photographic Material is used that contains at least two different types of silver images, the z. B. represent different partial color separations of a multicolored original and in which not all silver images from an oxidizing agent (e.g. reducible dyes or dye components) are surrounded by a silver bleach bath on this material allows it to act that completely or partially oxidizes the silver image surrounded by the oxidizing agent, andv that finally the remaining silver and the silver that may still be present here converts the remaining partial images into dye images by any method. 2. The method according to claim 1, characterized in that that such starting materials are used, the two images in two different Have layer depths. 3. The method according to claim 1 and 2, characterized marked that the first silver picture • into an inverted (»inversely proportional«) dye image in terms of its brightness values and the second silver foil is converted into a "proportional" dye image ·. 4. The method according to claim 1 to 3, characterized in that the first silver image with complete consumption of the silver of this image is converted into a dye image. 5. The method according to claim 1 to 3, characterized in that the first silver image only in part, appropriately for the larger part, and the other silver picture for the smaller part converted into an "inversely proportional" dye image and the remaining one Silver in a. "Proportional" dye image is transformed. 6. The method according to claim 1 to 5, characterized in that the Silfoerbilder received by putting at least a two-tone picture with a positive and a negative color image is copied onto a material containing silver halide that contains silver halide has different color sensitivity, such that the one color image preferably one, the other color image, preferably the other portion of the silver halide influences and, after the development of the latent silver images, these individually within themselves rectified color images transferred. 7. The method according to claim 1 to 5, characterized in that the silver images are obtained be by drawing a two-tone picture with one positive and one negative Color image portion copied onto a silver halide layer, which are differently color-sensitive Has layers corresponding to the original color images, and after development the latent silver images transforms them into a negative or positive color image. 1 sheet of drawings