US3726681A

US3726681A - Multilayered color photographic material

Info

Publication number: US3726681A
Application number: US00088224A
Authority: US
Inventors: E Bockley; G Pankow; B Morcher
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert AG
Priority date: 1969-11-22
Filing date: 1970-11-09
Publication date: 1973-04-10
Anticipated expiration: 1990-04-10
Also published as: DE1958709A1; CA956164A; FR2069779A5; JPS5021248B1; GB1336728A; US3684510A; BE758971A; CH536501A; DE1958709C2

Abstract

IN A MULTILAYERED COLOR COLOR PHOTOGRAPHIC MATERIAL AT LEAST ONE OF THE THREE COLORED PARTIAL IMAGES IS PRODUCED IN A DOUBLE LAYER CONSISTING OF TWO LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYERS, BOTH CONTAINING A COLOR-FORMING COUPLER FOR THE SAME PARTIAL IMAGE. ONE OF THE PARTIAL LAYERS, PREFERABLY THE UPPER ONE, IS MORE SENSITIVE TO LIGHT THAN THE OTHER BY FORM 0.1 TO 0.6 LOG I.T UNITS. THE COLORFORMING COUPLER IN THE MORE LIGHT-SENSITIVE LAYER COUPLES FROM 2 TO 20 TIMES MORE RAPIDLY THAN THAT IN THE LESS SENSITIVE LAYER. THE NECESSARY RATIO OF COUPLING VELOCITIES CAN BE ACHIEVED BY THE METHODS USED FOR INCORPORATING THE COUPLERS IN THE LAYERS. THE MATERIAL EXHIBITS LESS GRAININESS AND HIGHER SENSITIVITY.

Description

United States Patent 3,726,681 MULTILAYERED COLOR PHOTOGRAPHIC MATERIAL Gerrit Pankow, Opladen, and Bernhard Morcher, Rigobert Otto, and Erick Bockley, Leverkusen, Germany, assignors to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany No Drawing. Filed Nov. 9, 1970, Ser. No. 88,224 Claims priority, application Germany, Nov. 22, 1969, P 19 58 709.8 Int. Cl. G03c 1/76 US. Cl. 96-74 2 Claims ABSTRACT OF THE DISCLOSURE In a multilayered color color photographic material at least one of the three colored partial images is produced in a double layer consisting of two light-sensitive silver halide emulsion layers, both containing a color-forming coupler for the same partial image. One of the partial layers, preferably the upper one, is more sensitive to light than the other by from 0.1 to 0.6 log 1.! units. The colorforming coupler in the more light-sensitive layer couples from 2 to 20 times more rapidly than that in the less sensitive layer. The necessary ratio of coupling velocities can be achieved by the methods used for incorporating the couplers in the layers. The material exhibits less graininess and higher sensitivity.

The invention relates to a multilayered color photographic material in which at least one of the partial color images, is to be produced in a double layer.

As is well known, a multilayered color photographic material constructed in the usual manner in accordance with the theory comprises a red-sensitive silver halide emulsion layer which is arranged lowermost on a support of for example paper, cellulose ester or polyester and which contains a cyan-forming coupler incorporated in this layer in such a manner that it is resistant to diffusion. On this layer there is applied a green-sensitive layer which has a magenta-forming coupler incorporated in it. This is followed by a yellow filter layer and lastly a top layer which contains a yellow-forming coupler and which is usually not sensitized, i.e. it is only sensitive to the blue region of the spectrum. If desired, however, the arrangement of layers in a color photographic material may be reversed.

An increase in the sensitivity of multilayered color photographic materials is achieved, as described in British patent specification No. 818,687, if the emulsion layer which is directly applied to the support consists of two partial layers arranged one on top of the other, provided that the lower layer consists of a less sensitive silver halide emulsion and the upper layer consists of a highly sensitive silver halide emulsion. Both layers contain colorforming couplers in the same concentration and are sensitized to the same region of the spectrum. A material of this type has, however, the disadvantage in that the increase in sensitivity is accompanied by an increase in the graininess. This is an important consideration, especially for films which are used for taking photographs of originals, because it reduces the limit of magnification.

In order to overcome this disadvantage and to lower the graininess of the color images, in the process described in German Pat. No. 1,121,470 the layer which contains the more highly sensitive and coarser grained emulsion is adjusted to a lower color density than the less sensitive layer.

Belgian Pat. No. 713,806 describes a process for improving the sharpness of the image, according to which the two layers which are sensitized to the same region of the spectrum contain different couplers, the more highly sensitive emulsion layer containing so-called 4-equivalent couplers and the less sensitive layer so-called Z-equivalent couplers.

Both processes have numerous disadvantages, for example in the process according to German Pat. No. 1,121,- 470 the sensitivity of the emulsion is not fully utilized, especially if the emulsion is processed as reversal material. In negative color development, 2-equivalent couplers naturally produce a higher color fogging in the unexposed parts of the image than 4-equivalent couplers, and in addition they produce a pronounced color graininess due to the high intensifying effect in color development described in German Pat. No. 1,002,198.

The need, therefore, remained to improve the sensitivity and lower the graininess of the known color photographic materials in which at least one of the partial images, is to be produced in a double layer.

It is an object of the invention to provide a color photographic material which will have a very high sensitivity and will give rise to color images of great sharpness and, if possible, little graininess.

A multilayered color photographic material has now been formed for the production of colored images consisting of a yellow, a magenta and a cyan partial image, in which material at least one of the partial color images is to be produced in a double layer comprising a highly sensitive silver halide emulsion layer and a less sensitive silver halide emulsion layer, both of which layers contain a color-forming coupler for the particular partial image. In this color photographic material, the highly sensitive emulsion layer is more sensitive by from 0.1 to 0.6 log 1.2 units than the less sensitive emulsion layer, contains a color-forming coupler for the particular partial image which couples from 2 to 20 times more rapidly than the color-forming coupler in the less sensitive layer, and is preferably arranged above the less sensitive layer.

In multilayered color photographic materials, other layers may be interposed between the less sensitive and the more highly sensitive silver halide gelatin emulsion layer of a pair of layers for the production of a partial color image, e.g. one of the layers of a pair of layers for the production of another partial color image.

The ratio of coupler to silver may be different in the two layers of a pair. In a color negative material, the ratio of coupler to silver in the highly sensitive layer is preferably lower than in the less sensitive layer. In the case of reevrsal materials, the ratio of coupler to silver in the highly sensitive layer is preferably greater than in the less sensitive layer, for example 1.5 to 5 times greater.

The suitability of color-forming couplers for the preparation of the material acording to the invention does not depend on their chemical structure, although it is, of course, important that the couplers in the two layers of the pair should absorb substantially in the same region of the spectrum. Chemically, the color-forming couplers need not be identical. The important factor in every case is the ratio of coupling velocities of the color-forming couplers if incorporated in the layer.

According to the present invention the more sensitive emulsion layer contains the coupler with the higher coupling velocity and the less sensitive layer contains the coupler with the lower coupling velocity.

The coupling velocity of the couplers used can also be modified by the method used for incorporating the couplers in the emulsion layers. For example, a coupler which is incorporated in the emulsion in form of a solution in high boiling solvents, so-called oilformers, couples more slowly than the same coupler if incorporated in the absence of oilformers. Hence, follows, in a simple way, the

possibility to achieve the desired ratio of coupling velocities of the couplers used in the layer pairs. Couplers to be incorporated without oilformers are dissolved, as is known, in a low boiling solvent evaporating off as the layer dries, so that the coupler is present undissolved in a separate phase in the layer. Therefore, according to a preferred embodiment of the invention, the same coupler can be used in both partial layers of a double layer, but incorporated in the more sensitive layer in the absence of, and in the less sensitive layer in the presence of, an oilformer.

Couplers which are useful for the present invention with respect to the ratio of their coupling velocities can also be selected making use of the fact that in the layers hydrophilic water-soluble color-forming couplers couple more rapidly than hydrophobic color-forming couplers which are heterogeneously dispersed. Thus, for example, difiusion-fast color-forming couplers may be used both having the same basic structure, but one containing a water solubilizing group and being present in dissolved form as the more rapidly coupling compound in the more highly sensitive silver halide emulsion layer, while the heterogeneously dispersed hydorphobic coupler containing no water solubilizing group is incorporated in the less sensitive silver halide emulsion layer as the coupler with the lower coupling velocity.

Colored color-forming couplers may also be used according to the invention, these being introduced into the layer either alone or together with a colorless coupler having the same or at least a similar coupling velocity.

Optimum sensitivity and color graininess are obtained if the color-forming coupler in the less sensitive layer couples more slowly by a factor of from 3 to 5 than the coupler in the more highly sensitive layer. If the difierence in coupling velocities is substantially higher than the factor of from 3 to 5, it may be advantageous for the sake of obtaining a straight lined gradation curve to add a rapidly coupling coupler to the slow coupler, but the proportion of rapid coupler should not exceed 50% by weight.

Methods for determining coupling velocities are known. Particularly, the method of J. Eggers for determining the relative coupling velocities published in Mitteilungen aus den Forschungslaboratorien der Agfa Leverkusen Miiuchen, Volume III, page 81 ('Springer-Verlag Berlin-G6ttingen--Heidelberg, 1961) has proved to be very useful for choosing suitable color-forming couplers.

Rapidly coupling and slowly coupling couplers in the sense of the present invention can be selected also by means of simple tests. Rapidly coupling couplers are such couplers, which in the same emulsion exhibit the same constant threshold sensitivity independent of the quantity of coupler used. The sensitivity is defined as the log Lt-value of the gradation curve measured at the density 0.2 above fog. Slowly coupling couplers in the sense of the present invention exhibit a sensitivity clearly dependent on the quantity of coupler.

Examples of suitable slowly coupling and rapidly coupling color-forming couplers for the three substractive primary colors cyan, magenta and yellow are summarized in the table below.

(I) COUPLERS WHICH HAVE A RELATIVELY HIGH COUPLING VELOCITY Cyan-forming couplers:

1C1 OH IC-i Magenta-forming couplers:

IMl

Yellow-forming coupler:

(II) SLOWLY COUPLING COLOR-FORMING COUPLERS II 01 0 H o o N-CHz-Q I NHCO 0 11 HO 0 0 -o 0 OH 1102 OH HQCITICIEHH @4; ONHO l E s 03H I&OCH3

H03 0 H N lBHffl Magenta-forming couplers:

IIM1

i HO 0 O -CHzCONH i NH IIM2 i C -CnHas HOaS \N/ \O/ Yellow-forming coupler:

IIYI

The following examples illustrate the invention. The given parts are by weight throughout the examples:

EXAMPLE 1 Photographic material 1 Relatively slowly coupling magenta-forming couplers in both partial layers.

60 parts of a 0.1% methanolic solution of the green sensitizer:

CaHs

40 parts of a 1% aqueous solution of 4-hydroxy-6- methyl-l,3,3a,7-tetraazaindene and 240 parts of a aqueous solution of the magenta-forming coupler IIM3 are successively stirred at 40 C. into 1000 parts of a fine grained silver iodobromide gelatin emulsion of medium sensitivity containing 8% by weight of gelatin, 3.5% by weight of silver bromide and 0.3% by weight of silver iodide.

The mixture is cast on a layer support of cellulose triacetate and dried. The dry layer has a thickness of 3p. and contains 1.2 g. of silver in the form of silver halide per m 60 parts of a 0.1% methanolic solution of the aforesaid green sensitizer, 40 parts of a 1% aqueous solution. of 4-hydroxy-6-methyl-l,3,3a,7-tetraazaindene and 75 parts of a 5% aqueous solution of magenta-forming coupler -IlM3 are stirred into 1000 parts of a highly sensitive silver iodobromide gelatin emulsion containing 9.6% by weight of gelatin, 3.7% by weight of silver bromide and 0.2% by weight of silver iodide, at 40 C.

The mixture is applied to the aforesaid green-sensitive layer and dried. The second layer has a silver application of 1.4 g. of silver in the form of silver halide per m Photographic material 2 Green-sensitive double layer containing rapidly coupling magenta-forming couplers in both parts of the ayer.

The same quantities of green-sensitizer and of stabilizer are stirred into 1000 parts of the above-mentioned silver iodobromide emulsion of medium sensitivity, and in addition 480 parts of a 2.5% aqueous solution of magentaforming coupler 1M1. The mixture is applied to a layer support of cellulose triacetate and dried. When finished,

Green-sensitive double layer according to the invention having a slowly coupling color-forming coupler in the less sensitive silver halide emulsion layer and a rapidly coupling color-forming coupler in the highly sensitive silver halide emulsion layer.

The highly sensitive silver bromide emulsion layer of material 2 is applied on the silver iodobromide emulsion layer of medium sensitivity of material 1 and dried.

Processing.--The double layered materials described above are exposed behind a green filter in a conventional sensitometer behind a grey step wedge with a logarithmic density increase of 0.15 per step, and the materials are then processed as follows:

Minutes (1) Color-forming development 7 3 g. of diethylamin aniline sulfate 1 g. of hydroxylamine hydrochloride 2 g. of sodium sulfite 2.5 g. of potassium bromide 75 g. of sodium carbonate dissolved in water made up to 1000 ml.

Minutes (2) Washing 20 (3) Bleaching bath 5 g. of potassium ferricyanide dissolved in water made up to 1000 ml. (4) Washing 5 (5) Fixing bath 5 g. of sodium thiosulfate dissolved in water made up to 1000 ml.

The results obtained from the sensitometric interpretation are summarized in the table below.

This example also covers comparisons between various double layered materials containing color-forming coupiers of particular coupling velocities in the two parts of the double layer.

Material 1 Red-sensitive double layer containing slowly coupling cyan-forming couplers in both parts of the layer.

70 parts of a 0.1% methanolic solution of the red sensitizer:

2H5 30 parts of a 1% aqueous solution of 4-hydroxy-6-methyll,3,3a,7-tetraazaindene and 190 parts of an 8% aqueous solution of cyan-forming coupler IIC3 are introduced with stirring at 40 C. into 1000 parts of a fine grained silver iodobromide gelatin emulsion of medium sensitivity which contains 9.8% by weight of gelatin, 3.2% by weight of silver bromide and 0.2% by weight of silver iodide. The emulsion is applied to a layer support of cellulose triacetate and dried. The dry layer contains 1.5 g. of silver in the form of silver halide per mfi.

The above-mentioned quantities of red sensitizer and of stabilizer are added at the same temperature to 1000 parts of a highly sensitive silver iodobrornide gelatin emulsion containing 8% by weight of gelatin, 3.7% by weight of silver bromide and 0.2% by weight of silver iodide, and in addition 60 parts of an 8% aqueous solution of the same cyan-forming coupler are stirred in. The emulsion is applied to the layer described above and dried. The second layer contains 1.3 g. of silver in the form of silver halide per m5.

Material 2 Red-sensitive double layer containing rapidly coupling cyan-forming coupler in both parts of the layer.

The same silver iodobromide gelatin emulsion of medium sensitivity as described in the case of material 1 is prepared but instead of using the cyan-forming coupler mentioned there, 250 parts of a 6% aqueous solution of cyan-forming coupler 1C3 are stirred in. The emulsion is again applied to a layer support of cellulose triacetate and dried. The finished layer contains 1.2 g. of silver in the form of silver halide per 131.

The same quantities of red sensitizer and stabilizer are added to the highly sensitive silver iodobromide emulsion of material 1, and in addition 80 parts of a 6% aqueous solution of the above-mentioned cyan-forming coupler 1C3 are stirred in. The emulsion is applied to the layer of medium sensitivity mentioned above and dried. The finished layer contains 1.1 g. of silver in the form of silver halide per m.

Material 3 Red-sensitive double layer containing a slowly coupling cyan-forming coupler in the layer of medium sensitivity and a rapidly coupling cyan-forming coupler in the highly sensitive layer.

The highly sensitive silver iodobromide emulsion layer of material 2 is applied to the silver iodobromide emulsion layer of medium sensitivity of photographic material 1 and is dried. The two layers contain the quantities of silver halide per m. mentioned above.

Processing-The photographic materials 1, 2 and 3 are exposed in a conventional sensitometer behind a red filter and a grey step wedge with a logarithmic density increase of 0.15 per step, and are then processed as described in Example 1.

The results of the sensitometric interpretation are summarized in the following table.

It is seen from the table that, like in Example 1, material 3 has both the advantage of fine graininess of material 1 and the advantage of increased sensitivity of material 2.

EXAMPLE 3 Blue-sensitive double layered materials are compared in a manner similar to that used in the previous examples.

Material 1 Blue-sensitive layer containing slowly coupling yellowforming couplers in both parts of the layer.

30 parts of a 1% aqueous solution of 4-hydroxy-6- methyl-l,3,3a,7-tetraazaindene and 450 parts of a 5% aqueous solution of the yellow-forming coupler IIYI are stirred into 1000 parts of the silver iodobromide emulsion of medium sensitivity of Example 1 at 40 C. The emulsion is applied to a layer support of cellulose triacetate and dried. When finished, the layer contains 1.7 g. of silver in the form of silver halide per m.

The stabilizer solution mentioned above and 180 parts of a 5% aqueous solution of the same yellow-forming coupler are introduced with stirring at 40 C. into 1000 parts of the highly sensitive silver iodobromide emulsion of Example 1. The emulsion is applied to the aforesaid emulsion layer of medium sensitivity and dried. The highly sensitive layer contains 1.8 g. of silver in the form of silver halide per m.

Material 2 Highly sensitive double layer with rapidly coupling yellow-forming couplers in both parts of the layer.

The same quantities of stabilizer and 450 parts of a 5% aqueous solution of the rapidly coupling yellow-forming coupler IYl are stirred into 1000 parts of the silver iodobromide gelatin emulsion of medium sensitivity used for material 1. The emulsion is again applied to a layer support of cellulose triacetate and dried. The finished layer contains 1.4 g. of silver in the form of silver halide per m.

The same quantities of stabilizer and 180 parts of a 5% aqueous solution of the aforesaid yellow-forming coupler are stirred into 1000 parts of the highly sensitive 10 silver iodobromide emulsion of material 1. The emulsion is applied to the aforesaid layer of medium sensitivity and the whole material is dried. The highly sensitive emulsion layer contains 1.55 g. of silver in the form of silver halide per m..

Material 3 spond to those obtained in Examples 1 and 2. The material 3 is just as fine grained as material 1 in every part of the image but has the same sensitivity as material 2, which is higher than that of material 1, namely 0.3 logarithmic I .2. units.

EXAMPLE 4 Comparison of double layered materials in one of which the same color-forming coupler is introduced into both layers at different concentrations but by the same method, whereas in the other the same color-forming coupler is introduced into the two-layers by different methods.

Material 1 Coupler introduced into both layers by the same method.

The same parts of green sensitizer and of stabilizer and in addition 360 parts of a dispersion of color-forming coupler in gelatin are added to 1000 parts of the silver iodobromide emulsion of medium sensitivity of material 1 of Example 1. The emulsion is applied to a layer support of cellulose triacetate and dried. The finished layer contains 1.2 g. of silver in the form of the silver halides per m.

The dispersion of color-forming coupler in gelatin is prepared as follows: 20 parts of the magenta-forming coupler IM3 are dissolved in 40 parts of dibutyl phthalate and the dispersed in 300 parts of a 5% aqueous gelatin solution.

parts of the above described dispersion of colorforming coupler in gelatin are added to 1000 parts of the highly sensitive silver iodobromide emulsion of material 1 of Example 1 which has been sensitized and stabilized in the same manner. This mixture is applied to the above layer of medium sensitivity and dried. The second layer contains 1.4 g. of silver in the form of the silver halides per m9.

Material 2 Color-forming coupler incorporated by different methods.

The silver iodobromide emulsion of medium sensitivity is prepared in the same way as described above for material 1 and then applied to a layer support and dried.

parts of a dispersion of coupler in gelatin which contains the same color-forming coupler but no high boiling solvent (oil-former) are now added to 1000 parts of the above-mentioned highly sensitive silver iodobromide gelatin emulsion which has been sensitized and stabilized in the same manner. The dispersion of coupler in gelatin is prepared as follows:

10 parts of the same magenta-forming coupler 1M3 are dissolved in 30 parts of ethyl acetate and then dispersed in 150 parts of a 5% aqueous gelatin solution.

The above emulsion mixture is applied to the silver iodobromide emulsion layer of medium sensitivity and 1 1 dried. On drying, the ethyl acetate used as solvent for the color-forming coupler evaporates and the coupler is left in the solid form in the layer, The second layer contains 1.4 g. of silver in the form of the silver halides per m? after drying.

Processing.Materials l and 2 are exposed and processed as described in Example 1.

Sensitometric measurements show that material 2 has the graininess but is more sensitive by 0.2 log I.t units than material 1. This is due to the fact that the colorforming coupler present in solid form in the highly sensitive silver iodobromide emulsion layer in material 2 conples more rapidly than the color-forming coupler emulsitied in dissolved form in the highly sensitive emulsion layer of material 1.

EXAMPLE In the following example dififerent double layers are compared in color photographic reversal processing.

Material 1 The two parts of the double layer diifer in their sensitivity but both parts contain the same magenta-forming coupler at the same concentration.

400 parts of a 5% aqueous solution of the magentaforming coupler IIM3 are added to 1000 parts of the silver iodobromide gelatin emulsion of medium sensitivity of material 1 of Example 1, which has been sensitized to the green region of the spectrum and stabilized in the same manner. The emulsion is applied to a cellulose triacetate support and dried. The dry layer contains 1.2 g. of silver in the form of the silver halide per m.

The highly sensitive silver io dobromide gelatin emulsion of material 2 from Example 1 is now applied to their layer of medium sensitivity at the same silver concentration per m The emulsion was sensitized to the green region of the spectrum in the same manner and contained the same stabilizer. It also contained 400 parts of a 5% aqueous solution of the magenta-forming coupler IIM3.

Material 2 Double layer containing slowly coupling magentaforming coupler in the layer of medium sensitivity and a rapidly coupling magenta-forming coupler in the highly sensitive layer; the ratio of coupler to silver is approximately the same in both layers.

The same silver iodobromide emulsion layer of medium sensitivity is prepared as for material 1. The highly sensitive silver iodobromide gelatin emulsion layer from EX- ample l is applied to the aforesaid layer at the same silver concentration per m? and dried. The more sensitive emulsion had been sensitized to the green region of the spectrum in the same way as described in Example 1 and contains the same stabilizer. It also contained 800 parts of a 2.5% aqueous solution of the magenta-forming coupler IMl.

Material 3 Double layer containing a slowly coupling magenta forming coupler in the layer of medium sensitivity and a chemically different rapidly coupling magenta-forming coupler in the highly sensitive layer; the ratio of coupler to silver is considerably higher in the highly sensitive layer.

180 parts of a 5% aqueous solution of magenta-forming coupler IIM3 are added to 1000 parts of the silver iodobromide gelatin emulsion layer of medium sensitivity from Example 1, which layer has been sensitized to the green region of the spectrum in the same manner and contains the same stabilizer. The emulsion is applied to a cellulose triacetate support and dried. The finished layer has a silver concentration of 1.8 g. of silver in the form of silver halide per m. The ratio of coupler to silver is 0.23.

The highly sensitive silver halide layer of material 1 is applied to the aforesaid silver iodobromide gelatin emulsion layer of medium sensitivity. The ratio of coupler to silver in this highly sensitive silver halide layer is 0.51.

Processing.-The three double layered materials are exposed in a conventional sensitometer behind a green filter and a grey step wedge with a logarithmic density increase of 0.15. They are then all processed identically by the color photographic reversal process described in Photographic Chemistry by P. Glafkides, Volume 2, pages 631 and 632 published by the Fountain Press, London.

The three double layered materials all have substantially the same maximum density. In the sensitornetric interpretation, the point on the gradation curve situated 0.2 density units below the maximum density is chosen for comparing the sensitivities.

The comparison shows that materials 2 and 3 are more sensitive by about 0.25 log Lt units than material 1. The magenta image of material 3 has a substantially finer grained structure than the color images obtained with the two other materials.

EXAMPLE 6 In this example the properties of the double layered materials of Examples 1 to 3 are compared in the context of a color photographic multilayered material.

Color photographic material 1 The following layers are applied to a cellulose triacetate layer support as described in Examples 1 to 3:

(a) the red-sensitive double layer of material 1 according to Example 2,

(b) an intermediate gelatin layer,

(c) the green-sensitive double layer of material 1 according to Example 1,

(d) an intermediate gelatin layer,

(e) a yellow filter layer containing colloidal silver as filter dye,

(f) the blue-sensitive double layer of material 1 according to Example 3.

Color photographic material 2 The material is built up in the same way as the aforesaid material 1 but the double layers of material 2 according to Examples 1 to 3 are applied.

Color photographic material 3 The material is built up in the same way as the aforesaid material 1 but the double layers of material 3 from Examples 1 to 3 are used.

Processing-Processing is carried out as described in Example 1, but exposure in the sensitometer is carried out with white light behind a grey step wedge.

The results of sensitometric interpretation from Examples 1 to 3 are confirmed here. Materials 2 and 3 have a higher sensitivity by about 0.3 log I.t units and material 3 in addition has the excellent fineness of grain of material 1.

What we claim is:

1. In a multilayered silver halide emulsion negative color photographic material for the production of a combination of images each image having its own color different from that of each of the other images, and in which material there is a pair of silver halide emulsion layers for at least one of the images, both emulsion layers of a pair containing a color-forming coupler for the particular color of that image, the improvement according to which one of the emulsion layers of a pair is more sensitive by 0.1 to 0.6 log [.1 units than the other, its coupler couples from 2 to 20 times more rapidly than that of the other, is arranged above the other, and has a coupler-to-silver 13 1.4 ratio less than that of the other, and the color couplers FOREIGN PATENTS of the photographic material are all 4-equivalent cou- 923 045 4/1963 Great Britain plers. l

2. The combination of claim 1 in which the more rapid NORMAN TORCHIN Primary Examiner color coupler couples from 3 to 5 times more rapidly 5 than the slower color coupler. J. R. HIGHTOWER, Primary Examiner References Cited US. Cl. X.R. UNITED STATES PATENTS 96-67 3,516,831 6/1970 Wolf 96-74