Photographic negative-working colour film element

Abstract

 A photographic negative-working colour film element is disclosed comprising on a transparent film support, at least one red-sensitized silver halide emulsion layer comprising at least one cyan-forming coupler, an intermediate layer, at least one green-sensitized silver halide emulsion layer comprising at least one magenta-forming coupler, at least one blue-sensitive silver halide emulsion layer comprising at least one yellow-forming coupler, and a yellow filter layer, situated between the green-sensitive layer(s) and the blue-sensitive layer(s), characterised in that the said yellow filter layer comprises a synthetic clay.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a photographic colour negative film element with an improved colour hue.

BACKGROUND OF THE INVENTION

[0002] Colour negative films are light-sensitive recording film elements having a flexible transparent support and light-sensitive layers composed in such a way that by normal exposure to light in a camera and subsequent chemical processing a negative colour image is obtained. Colour intermediate films are negative working light-sensitive recording elements also having a flexible transparent support and light-sensitive layers composed in such a way that by exposure to light through an original colour negative and subsequent chemical processing a duplicate positive of said original colour negative is obtained and that by exposure to light of another colour intermediate film through said duplicate positive and subsequent chemical processing a duplicate of said original colour negative is obtained.

[0003] Both types of colour films basically consist of a transparent film support carrying in the given order at least one red-sensitized silver halide emulsion layer, at least one green-sensitized silver halide emulsion layer, at least one blue-sensitive silver halide emulsion layer, and a gelatin antistress layer. Between the emulsion layers intermediate layers of a hydrophilic colloid, mostly gelatin, are provided for better colour separation. The intermediate layer beneath the blue-sensitive layer(s) currently is a yellow filter layer that absorbs the blue light not absorbed by the blue-sensitive layer(s) and transmits the red and green light to which the lower layers are sensitive. Between the green- and red-sensitized layers a gelatin intermediate layer is often used, which helps to prevent interactions between the sensitive layers during coating operations and helps to prevent colour contaminations by oxidized developer wandering from one layer into another during the development reaction.

[0004] One method to improve the colour rendition of colour negative or a colour intermediate film consists in changing the absorption spectrum of the spectrally sensitized silver halide crystals, in order to absorb exposure light in three well-defined spectral regions, being the blue-light, the green-light and the red-light absorbing regions respectively. A minimum overlap of the said regions is highly requested therefor. As there are spectral sensitizers or combinations thereof offering an adapted absorption in favour of true colour rendition which are less non-migratory, the problem arises that side-absorptions are leading to colour contaminations.

OBJECTS OF THE INVENTION

[0005] It is a first object of this invention to get a true colour rendition, without side-absorptions and without colour contamination.

[0006] It is a second object of this invention to get a negative working colour material having a sufficient speed and an excellent image quality, especially sharpness.

SUMMARY OF THE INVENTION

[0007] A photographic negative-working colour film element is disclosed comprising on a transparent film support, at least one red-sensitized silver halide emulsion layer comprising at least one cyan-forming coupler, an intermediate layer, at least one green-sensitized silver halide emulsion layer comprising at least one magenta-forming coupler, at least one blue-sensitive silver halide emulsion layer comprising at least one yellow-forming coupler, and a yellow filter layer, situated between the green-sensitive layer(s) and the blue-sensitive layer(s), characterised in that the said yellow filter layer comprises a synthetic clay.

DETAILED DESCRIPTION.

[0008] According to this invention at least one synthetic clay is added to the yellow filter layer of the negative-working colour film element. Synthetic clays are clearly differing from natural clays in that the layered structure and composition are well-known and predetermined, and that the addition of specific additives can introduce (new) desired properties.

[0009] Natural clays are essentially hydrous aluminum silicates, wherein alkali metals or alkaline-earth metals are present as principal constituents. Also in some clay minerals magnesium or iron or both replace the aluminum wholly or in part. The ultimate chemical constituents of the clay minerals vary not only in amounts, but also in the way in which they are combined or are present in various clay minerals. It is also possible to prepare synthetic clays, so that more degrees of freedom can lead to reproducible tailor made clay products for use in different applications.

[0010] So from the natural clays smectite clays are well-known. For the said smectite clays some substitutions in both octahedral and tetrahedral layers of the crystal lattice occur, resulting in a small number of interlayer cations. Smectite clays form a group of "swelling" clays which take up water and organic liquids between the composite layers and which have marked cation exchange capacities.

[0011] Synthetic chemically pure clays have been produced having an analogous structure as smectite clay and are now available. So the preferred synthetic smectite clay additive for the purposes of this invention is LAPONITE JS, trade mark products of LAPORTE INDUSTRIES Limited, London. Organophilic clays and process for the production thereof have been described in EP-Patent 161 411 B1.

[0012] LAPONITE JS is described as a synthetic layered hydrous sodium lithium magnesium fluoro-silicate incorporating an inorganic polyphoshate peptiser. The said fluoro-silicate appears as free flowing white powder and hydrates well in water to give virtually clear and colourless colloidal dispersions of low viscosity, also called "sols". On addition of small quantities of electrolyte highly thixotropic gels are formed rapidly. The said thixotropic gels can impart structure to agueous systems without significantly changing viscosity. An improvement of gel strength, emulsion stability and suspending power can be observed by making use of it in the said agueous systems. Further advantages are the large solid surface area of about 350 m²/g which gives excellent adsorption characteristics, its stability over a wide range of temperatures, its unique capability to delay gel formation until desired and its synergistic behaviour in the presence of thickening agents. Further, its purity and small particle size ensures an excellent clarity. In aqueous solutions of many polar organic solvents it works as a very effective additive.

[0013] LAPONITE RDS is described as a synthetic layered hydrous sodium lithium magnesium silicate with analogous properties as LAPONITE JS.

[0014] Laponite clay as a synthetic inorganic gelling agent for agueous solutions of polar organic compounds has been presented at the Symposium on "Gums and Thickeners", organised by the Society of Cosmetic Chemists of Great Britain, held at Oxford, on 14th October 1969. In Laporte Inorganics Laponite Technical Bulletin L104/90/A a complete review about the structure, the chemistry and the relationship to natural clays is presented. Further in Laporte Inorganics Laponite Technical Bulletin L106/90/c properties, preparation of dispersions, applications and the product range are disclosed. A detailed description of "Laponite synthetic swelling clay, its chemistry, properties and application" is given by B.J.R. Mayes from Laporte Industries Limited.

[0015] In praxis the primary particles are platelets having a diameter of about 0.025 µm and a thickness of about 0.001 µm.

[0016] In negative-working colour film elements, it is common practice to make use of a yellow filter layer, situated under the light-sensitive layers which are sensitive to incident blue light. The main compound therein is the yellow dye, having the desired absorption spectrum in order to act as a suitable filter for blue light. Instead of a yellow dye, colloidal silver can be used, as, depending on the particle size and the particle size distribution the required region of the wavelength spectrum can be covered. The said silver particles can easily be removed in the bleaching step of the processing cycle. In addition it is important to add a dye absorbing ultra-violet radiation in order to avoid false colour generation due to side-absorptions as silver halide crystals in the green-sensitive and the red-sensitive layer, although spectrally sensitised, remain intrinsically sensitive to the said radiation. Another important compound in the yellow filter layer is the colourless coupler which prevents the wandering of oxidised developer from the green-sensitised layer to the blue-sensitive layer and vice versa in order to prevent colour contamination.

[0017] It has now unexpectedly been found that the addition of at least one synthetic clay to the yellow filter layer gives rise to a true colour rendition, without side-absorptions and without colour contamination.

[0018] According to this invention, addition of the said synthetic clay or a mixture of synthetic clays is not restricted to the filter layer, but addition to at least one other hydrophilic layer is recommended. So, e.g., addition to the interlayer coated between the support and the red-sensitized silver halide emulsion layer, coated closest to the support, and/or, even more preferred, to the interlayer between the red-sensitized and the green-sensitized silver halide emulsion layers is highly recommended.

[0019] In an embodiment according to this invention the photographic negative-working film element is built up as has been described in EP-A 582 000. The said non-light-sensitive layers disclosed therein, which, according to this invention optionally comprise at least one synthetic clay, are a blue antihalation layer, coated between the support and the red-sensitized silver halide emulsion layer, coated closest to the support, wherein said blue antihalation layer comprises at least one blue non-diffusing dye in a hydrophilic colloid, said dye absorbing red light.

[0020] It is clear that in the layer arrangement as described in EP-A 0 582 000 the yellow filter layer, according to this invention, always comprises at least one synthetic clay and at least one yellow non-diffusing dye in a hydrophilic colloid, said dye absorbing blue light and wherein the said dye(s) is (are) removable and/or decolourizable in a processing baths.

[0021] According to that invention in the hydrophilic non-light-sensitive layers of the photographic negative-working colour film element according to this invention, the said yellow non-diffusing dye is represented by the general formula (I)

wherein

n represents 0;

each of p and q independently represent 0, 1 or 2;

Q represents the atoms necessary to form an acidic nucleus; each of R¹ and R² independently represents hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, COOR³, NHCOR⁴ or NHSO₂R⁵ with R³ representing hydrogen or substituted or unsubstituted alkyl, each of R⁴ and R⁵ independently representing substituted or unsubstituted alkyl, or substituted or unsubstituted aryl,

X represents OR⁶, SR⁶ or NR⁷R⁸, wherein

R⁶ represents H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl and

each of R⁷ and R⁸ which may be the same or different represents hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl or the necessary atoms to form a ring together with the N-atom to which they are attached and the C-atom of the phenylene ring in ortho position with respect to said N-atom; R⁷ and R⁸ together may also represent the necessary atoms to form a ring with the N-atom to which they are attached;

L₁, L₂, L₃ represent substituted or unsubstituted methine with the proviso that, if substituted, at least one of L₁, L₂ or L₃ must be substituted by -CONR⁹R¹⁰; -COOR⁹; -CN;

R⁹ and R¹⁰ which may be the same or different represent hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or wherein -CON(R¹¹)- wherein R¹¹ represents atoms to form a ring with an atom of Q, defined hereinbefore;
and wherein at least one of R¹ to R¹¹ contains an ionizable group.

[0022] In the yellow filter layer of the material according to this invention, wherein synthetic clay(s) is (are) always present, a particularly preferred yellow non-diffusing dye is 1-(p-carboxyphenyl)-3-methyl-4-(p-hydroxybenzylidene)-2-pyrazolin-5-one.

[0023] In another embodiment the said yellow non-diffusing dye is represented by the general formula (II)

wherein

m= 0;

each of R¹ and R² has the same meaning as given in formula (I), and at least one of R¹ and R² in formula (II) has an ionizable group.

[0024] According to the invention described in EP-A 0 582 000 in the photographic material in this invention there is also a blue antihalation layer, between the support and the red-sensitized silver halide emulsion layer, coated closest to the support, comprising a blue non-diffusing dye in a hydrophilic colloid, said dye absorbing red light.

[0025] In the said blue antihalation layer of the photographic material according to this invention, said layer optionally comprising at least one synthetic clay, an oxonol dye represented by the general formula (II) given hereinbefore is present, wherein m= 2

[0026] In another embodiment in the said blue antihalation layer of the photographic material according to this invention, wherein said layer optionally comprises at least one synthetic clay, a dye represented by the general formula (III) is present.

In the said formula (III) each of R⁵ and R⁶, which may be the same or different, represents hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and each of R³ and R⁴, which may be the same or different, represents one of the groups represented by R¹ and R², or a cycloalkyl group.

[0027] A particularly preferred blue non-diffusing dye in the material according to this invention is the pentamethine oxonol-type barbituric acid derivative dye being the ammonium salt of (1,5-bis-[1-H-3-(p-methoxyphenyl)-barbituric acid]-pentamethine oxonol).

[0028] Particularly preferred in the interlayer between the layers sensitive to red and green light respectively of the material according to this invention, said interlayer optionally containing at least one synthetic clay, is a green-light absorbing non-diffusing dye.

[0029] In a preferred embodiment said dye working as a antihalation dye is a merostyryl dye having the general formula (I) wherein n equals 1.

[0030] In another embodiment said green-light absorbing dye is an oxonol dye having the general formula (II), wherein m equals 1.

[0031] In a futher preferred embodiment the said dye corresponds to the formula (IV), given hereinafter:

[0032] Particularly preferred in the photographic element according to this invention is the presence, in solid dispersed or microprecipitated state of the said yellow non-diffusing merostyryl dye and/or the said green-light absorbing non-diffusing antihalation dye and/or the blue non-diffusing dye.

[0033] Preferred methods to prepare the said dyes in the solid dispersed or microprecipitated state have been described in the unpublished EP-A No. 94203766, filed December 27, 1994, which is incorporated herein by reference.

[0034] The thickness of the yellow filter layer is not critical, though generally a thickness of 0.5 to 3 µm is used. The thickness and the amount of the dyes present therein are preferably chosen in such a way that the resulting antihalation layer has an optical density of about 0.5 to about 1.5 as measured in its own absorption range. The amount of the yellow dye in the yellow filter layer may vary from 10 mg to 750 mg per m2 and more preferably from 25 to 250 mg per m2. It is clear that the thinner the coated layers, the smaller the light scattering and the sharper the images. Thin coated layers are often related with the possibility to coat less silver emulsion crystals per surface unit, but this is only possible if an optimised relation between crystal size and speed has been reached, eventually with the aid of development accelerators and, especially in colour negative materials, with the aid of suitable development inhibiting releasing couplers, also called DIR-couplers. Particularly preferred herein is the colourless DIR-coupler corresponding to the formula (V) hereinafter, which can be used in at least one of the hydrophilic layers of the material according to this invention. The said DIR-coupler is well-known from DE 3,644,416 and from US-P's 4,049,458; 4,870,000 and 5,021,332.

[0035] The presence of these dyes in filter layers of the material according to this invention is particularly in favour of sharpness of the said material. Moreover the use of carbon black in the surface layer of the back side can be avoided. As in that case its removal is not required, the processing baths are not made dirty.

[0036] According to this invention the synthetic clay present in the yellow filter layer and, optionally, in at least another non-light-sensitive hydrophilic layer, in particular the interlayer between the red and green sensitive layers and/or the layer between the support and the red-sensitive layers, is a synthetic smectite clay.

[0037] Preferred clays present in the yellow filter layer are synthetic layered hydrous sodium lithium magnesium silicates and synthetic layered hydrous sodium lithium magnesium fluoro-silicates and more preferably LAPONITE RDS and LAPONITE JS, both trademark names of LAPORTE INDUSTRIES Limited, London.

[0038] Preferred synthetic clays optionally present in the other hydrophilic non-light-sensitive layers adjacent to the green-sensitised and/or red-sensitised layer(s) are synthetic layered hydrous sodium lithium magnesium fluoro-silicates and more preferably the already mentioned LAPONITE JS.

[0039] In the photographic element according to this invention the said synthetic clay(s) is (are) present in an amount of at least 10% by weight versus the amount of hydrophilic colloid present in the yellow filter layer and, optionally, in at least another hydrophilic non-light-sensitive layer. Preferred amounts of synthetic clay added to at least one of the hydrophilic layer(s), and to the yellow filter layer in particular, are from 10 to 250 mg/m², preferably from 20 to 200 mg/m² and more preferably from 25 to 150 mg/m².

[0040] In a preferred embodiment, at least one of the hydrophilic non-light-sensitive layers according to this invention comprise at least one development accelerator in order to enhance the sensitivity of the adjacent light-sensitive layers. Especially preferred layers are the protective antistress layer, coated adjacent to the most sensitive blue-light sensitive silver halide emulsion layer and the interlayer between the red- and green-sensitised emulsion layers, adjacent to the most sensitive red-sensitised emulsion layer.

[0041] A particularly preferred development accelerator used in at least one of the said hydrophilic non-light-sensitive layers, inclusive the yellow filter layer, is the compound having the general formula (VI)

        R[O-CH₂-CH₂-S-(LINK¹-S)_x-CH₂CH₂-O-(LINK²)]_y-OR     (VI)

wherein
each of LINK¹ and LINK² which may be the same or different represents a divalent linking group; R represents H, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or an acyl group; x is 1 or 2, and y varies from 2 to 20.

[0042] The hydrophilic colloid binder of the layers containing the dyes according to the present invention is usually gelatin. Other hydrophilic colloids such as casein, polyvinyl alcohol, poly-N-vinyl pyrrolidone, sodium alginate, sodium carboxymethylcellulose, etc., can also be used either or not in combination with gelatin. In a further embodiment at least one of the hydrophilic layers of the photographic element according to this invention further comprises colloidal silica. Suitable silica sols are commercially available such as the "Syton" silica sols (a trademarked product of Monsanto Inorganic Chemicals Div.), the "Ludex" silica sols (a trademarked product of du Pont de Nemours & Co., Inc.), the "Nalco" and "Nalcoag" silica sols (trademarked products of Nalco Chemical Co), the "Snowtex" silica sols of Nissan Kagaku K.K. and the "Kieselsol, Types 100, 200, 300, 500 and 600" (trademarked products of Bayer AG). Particle sizes of the silica sol particles are in the range from 0.003 µm to 30 µm. The smaller particles in the range from 0.003 µm to 0.3 µm are preferred as its specific surface is larger and as its activity will be more effective.

[0043] Other compounds present in the multilayer colour photographic element according to this invention are well-known by everyone skilled in the art of photography, as described, e.g. in Research Disclosure 36544, published September 1994, which is incorporated herein by reference. In this reference, we especially refer to the chapters concerning emulsion grains and their preparation (Chapter I); vehicles, vehicle extenders, vehicle-like addenda (Chapter II); emulsion washing (chapter III); chemical sensitisation (chapter IV); spectral sensitisation (chapter V); UV dyes (chapter VI); antifoggants and stabilisers (chapter VII); absorbing materials (chapter VIII); coating physical property modifying addenda (chapter IX); dye image formers and modifiers (chapter X); layers and layer arrangements (chapter XI) inasfar as applicable to this invention and especially features applicable only to color negative (chapter XII).

[0044] So in favour of less graininess it is particularly recommended to use a triple-layer arrangement, especially for the red- and green-sensitised layers, wherein the fine-tuned choice of the ratio of coated silver amount to the amount of colour coupler will be decisive for lowering graininess.

[0045] From the same RD 36544 we further take into account the valuable information about exposure (chapter XVI) and development (chapter XIX).

[0046] Particularly concerning silver halide emulsions, although crystals with whatever a crystal habit can be used, particularly crystals having a tabular habit are preferred, and more preferred the spectrally sensitised ones. So the green-sensitised and red-sensitised emulsion crystals are preferably composed of tabular silver halide crystals, although tabular crystals in the blue-sensitive layer are not excluded. The silver halide emulsions in the layers of the colour negative photographic element according to this invention are preferably silver bromoiodide emulsions having an iodide content from 0.4 to 3 mole %, and more preferably from 0.5 to 1.5 mole % for colour intermediate films and from 3 to 15 mole %, and more preferably from 3 to 9 mole % in the less sensitive layer, even more preferably from 4 to 7 mole %; and more preferably from 5 to 15 mole % and even more preferably from 7 to 15 mole % in the most sensitive layers of each colour sensitive arrangement for colour negative recording films. These silver bromoiodide emulsion crystals can be prepared in gelatin, but also colloidal silica can be a very useful protective colloid as has been illustrated in the unpublished EP-A No. 94200933, filed April 6, 1994.

[0047] The choice of the most suitable spectral sensitisers for the said silver bromoiodide crystals is also a very important factor to get true colour rendition. Especially green-sensitisation is very critical and, according to this invention, it has been found that a combination of three spectral sensitisers, having the formulae SS-1, SS-2 and SS-3 is highly preferred (see Example 2).

[0048] The transparent film support of the photographic colour negative or colour intermediate film element of the present invention is a film of cellulose triacetate, a polyalkylene terephthalate, e.g., polyethylene terephthalate, polyethylene naphthalate or polycarbonate.

[0049] It may be advisable to provide the transparent film support with a primer coating or a subbing layer before the application of the blue antihalation layer or to pretreat the support superficially according to known techniques such as an electrical treatment with a high voltage corona, etc. An interesting primer coating for application between a polyethylene terephthalate support and the blue antihalation layer has been described, e.g., in US-P 4,132,552.

[0050] According to this invention, the photographic negative-working colour film element, being a colour negative recording film or a colour intermediate film, is coated with a backing layer on the side of the transparent film support that is opposite to that carrying the emulsion layers and is provided with an antistatic layer comprising an electroconductive polymer as, e.g., described in US-P 4,089,997, preferably an antistatic layer comprising polystyrene sulphonic acid sodium salt and even more preferred polyethylene dioxy thiophene. This antistatic layer may comprise polymer beads as described in EP-S 0,080,225, these beads protruding from the antistatic layer surface and consequently acting as spacing agents to reduce contact with adjacent surfaces.

[0051] The following examples illustrate the present invention without however limiting it thereto.

EXAMPLE 1

[0052] Samples of colour negative film elements A and B were made. Each sample had a transparent film support, a subbing layer, a red-sensitized silver halide emulsion layer comprising a cyan-forming coupler, an intermediate gelatin layer, a green-sensitized silver halide emulsion layer comprising a magenta-forming coupler, a yellow filter layer, a blue-sensitive silver halide emulsion layer comprising a yellow-forming coupler, and an antistress layer. All samples were identical except for the composition of the yellow filter layer YFL, as explained hereinafter.

[0053] In the materials A and B, the corresponding yellow filter layer, called YFL-A and YFL-B respectively, were containing (per sq.m) as main components:

• 0.7 mmole of the product (V-1) as ultraviolet absorbing agent
  
  
• 100 mg of polymethylmethacrylate matting agent (particle size: ca. 0.13 µm)
• 0.85 of the yellow dye (D-1)
  
  
• 0.006 mole of the product (V-2) as development activating agent
  
  
• 0.8 mmole of the product (V-3) as colourless coupling agent

Y = 27% ± 2%; Z = 73% ± 2%
According to this invention 150 mg/m² of Laponite RDS were additionally added to YFL-B.
Further the same coating additives and preservatives were added to both materials.

[0054] Both elements A and B had a blue antihalation layer between the support and the red-sensitized silver halide emulsion layer, the blue antihalation layer having a thickness of 1 µm and comprising 50 mg of the blue dye B-01 (in its ammonium salt form) and 0.7 g of gelatin per m2.

[0055] A sample of each of the materials A and B was individually placed in contact with a transparent chart or wedge and a first sample of each was selectively exposed to green light.

[0056] After colour development, the secondary absorption in the blue wavelength region of the visible spectrum was compared for both materials using a blue filter layer therefor.

[0057] As can be concluded from the Figure 1, wherein the sensitometric curves obtained after filtering the blue, the green and the red light respectively from the processed materials A and B are given, a remarkable and unexpected lower secondary absorption of blue light is obtained if synthetic clay is present in the yellow filter layer.

EXAMPLE 2

[0058] Samples of colour negative film elements C, D and E were made. Sample C had the same composition as sample A (see Example 1) except for the spectral sensitisation of the silver bromoiodide crystals in the green-light sensitive emulsion layer having the highest speed (farther from the support in the green-sensitive layer packet). The crystals of samples C, D and E were each spectrally sensitised with: 0.176 mmole of SS-3; SS-4 and SS-5, the formulae of which are given hereinafter in a molar ratio of 75:20:5.

[0059] In the materials C, D and E, the corresponding yellow filter layer, called YFL-C, YFL-D and YFL-E respectively, were containing the same components in the same amounts as given in Example 1. According to this invention 25 mg/m² of Laponite RDS were additionally added to YFL-B; 50 mg/m² to YFL-C. Further the same coating additives and preservatives were added to both materials as in Example 1.

[0060] A sample of each of the materials C, D and E was individually placed in contact with a transparent chart or wedge and selectively exposed to green light. After colour development, the secondary absorption in the blue wavelength region of the visible spectrum was compared for both materials.

[0061] As can be concluded from the Figure 2, wherein the sensitometric curves obtained after filtering the blue, the green and the red light respectively from the processed materials C, D and E has been given, a remarkable and unexpected lower secondary absorption of blue light is obtained if synthetic clay is present in the yellow filter layer. Moreover a lower amount of the said clay is required when the most sensitive emulsion crystals in the green-sensitive layer are spectrally sensitised with the new combination of spectral sensitising dyes.
Practical tests were sufficiently convincing for every examiner, whether or not exercised, that a substantial improvement was made by addition of synthetic clays to the yellow filter layer, especially in combination with an improved spectral sensitisation for the green-sensitised silver halide emulsion crystals as set forth above.

Claims

1. Photographic negative-working colour film element comprising on a transparent film support, at least one red-sensitized silver halide emulsion layer comprising at least one cyan-forming coupler, an intermediate layer, at least one green-sensitized silver halide emulsion layer comprising at least one magenta-forming coupler, at least one blue-sensitive silver halide emulsion layer comprising at least one yellow-forming coupler, and a yellow filter layer, situated between the green-sensitive layer(s) and the blue-sensitive layer(s), characterised in that the said yellow filter layer comprises a synthetic clay.

2. Photographic negative-working film element according to claim 1, wherein the said yellow filter layer comprises at least one yellow non-diffusing dye in a hydrophilic colloid, said dye absorbing blue light and wherein the said dye(s) is (are) removable and/or decolourizable in a processing bath.

3. Photographic negative-working colour negative film element according to claim 2, wherein the said yellow non-diffusing dye is represented by the general formula (I)

wherein

n represents 0;

each of p and q independently represent 0, 1 or 2;

Q represents the atoms necessary to form an acidic nucleus;

each of R¹ and R² independently represents hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, COOR³, NHCOR⁴ or NHSO₂R⁵ with R³ representing hydrogen or substituted or unsubstituted alkyl, each of R⁴ and R⁵ independently representing substituted or unsubstituted alkyl, or substituted or unsubstituted aryl,

X represents OR⁶, SR⁶ or NR⁷R⁸, wherein

R⁶ represents H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl and

each of R⁷ and R⁸ which may be the same or different represents hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl or the necessary atoms to form a ring together with the N-atom to which they are attached and the C-atom of the phenylene ring in ortho position with respect to said N-atom; R⁷ and R⁸ together may also represent the necessary atoms to form a ring with the N-atom to which they are attached;

L₁, L₂, L₃ represent substituted or unsubstituted methine with the proviso that, if substituted, at least one of L₁, L₂ or L₃ must be substituted by -CONR⁹R¹⁰; -COOR⁹; -CN;

R⁹ and R¹⁰ which may be the same or different represent hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or wherein -CON(R¹¹)- wherein R¹¹ represents atoms to form a ring with an atom of Q, defined hereinbefore;

and wherein at least one of R¹ to R¹¹ contains an ionizable group.

4. Photographic negative-working colour negative film element according to claim 2, wherein the said yellow non-diffusing dye is represented by the general formula (II)

wherein

m= 0;

each of R¹ and R² has the same meaning as given in formula (I), and at least one of R¹ and R² in formula (II) has an ionizable group.

5. Photographic negative-working colour film element according to claim 2 or 3, wherein said yellow non-diffusing dye is 1-(p-carboxyphenyl)-3-methyl-4-(p-hydroxybenzylidene)-2-pyrazolin-5-one.

6. Photographic negative-working film element according to any of claims 1 to 5, wherein there is a blue antihalation layer, between the said support and the red-sensitized silver halide emulsion layer, coated closest to the support, comprising a blue non-diffusing dye in a hydrophilic colloid, said dye absorbing red light.

7. Photographic negative-working colour film element according to claim 6, wherein the said blue non-diffusing dye present in the blue antihalation layer is an oxonol dye represented by the general formula (II) wherein m= 2.

8. Photographic negative-working colour film element according to claim 6, wherein the said blue non-diffusing dye present in the blue antihalation layer is an oxonol dye represented by the general formula (III)

in which each of R⁵ and R⁶, which may be the same or different, represents hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and each of R³ and R⁴, which may be the same or different, represents one of the groups represented by R¹ and R², or a cycloalkyl group.

9. Photographic negative-working colour film element according to claim 7 or 8, wherein the said blue non-diffusing dye is the pentamethine oxonol-type barbituric acid derivative dye being the ammonium salt of (1,5-bis- [1-H-3-(p-methoxyphenyl)-barbituric acid]-pentamethine oxonol).

10. Photographic negative-working film element according to claim 1 to 9, wherein there is a green-light absorbing non-diffusing antihalation dye between the red-sensitized and the green-sensitized silver halide emulsion layers, comprising at least one green-light absorbing non-diffusing antihalation dye.

11. Photographic negative-working colour negative film element according to claim 10, wherein the said green-light absorbing non-diffusing antihalation dye is a merostyryl represented by the general formula (I) wherein n represents 1.

12. Photographic negative-working colour film element according to claim 10, wherein said green-light absorbing dye is an oxonol dye having the general formula (II), wherein m equals 1.

13. Photographic negative-working colour film element according to any of claims 2 to 7, wherein the said yellow non-diffusing dye and/or the said green-light absorbing non-diffusing antihalation dye and/or the blue non-diffusing dye are present in solid dispersed or microprecipitated state.

14. Photographic negative-working colour film element according to any of claims 1 to 13, wherein the said synthetic clay is a synthetic smectite clay.

15. Photographic negative-working colour film element according to any of claims 1 to 14, wherein said synthetic clay is present in an amount of at least 10% by weight versus the amount of hydrophilic colloid present in the yellow filter layer.

16. Photographic negative-working colour film element according to any of claims 1 to 15, wherein at least one of the said hydrophilic non-light-sensitive layers comprises at least one development accelerator.

17. Photographic negative-working colour film element according to claim 16, wherein said development accelerator is compound having the general formula (V)

        R[O-CH₂-CH₂-S-(LINK¹-S)_x-CH₂-CH₂-O-(LINK²)]_y-OR     (V)

wherein
each of LINK¹ and LINK² which may be the same or different represents a divalent linking group; R represents H, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or an acyl group; x is 1 or 2, and y varies from 2 to 20.

18. Photographic negative-working colour film element according to any of claims 1 to 17, wherein said hydrophilic layer comprise colloidal silica.

19. Photographic negative-working colour film element according to any of claims 1 to 18, wherein the side of the transparent film support that is opposite to the one carrying the emulsion layers is provided with an antistatic layer comprising an electroconductive polymer.

Drawing