Photographic colour negative or colour intermediate film element

Abstract

 Photographic colour negative or colour intermediate film element comprising a transparent film support and coated thereon in succession, a blue antihalation layer, 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, a yellow filter layer, at least one blue-sensitive silver halide emulsion layer comprising at least one yellow-forming coupler, and an antistress layer, wherein said blue antihalation layer comprises at least one blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye in dispersed state in a hydrophilic colloid, said dye absorbing red light and being removable and/or decolourizable in a processing bath.

Description

[0001] The present invention relates to a photographic colour negative or a colour intermediate film element comprising light-absorbing antihalation layers.

[0002] Colour negative films are light-sensitive recording 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 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. Usually, the side of the transparent film support opposite to that carrying the emulsion layers is coated with a carbon black antihalation back layer. A carbon black antihalation back layer indeed provides excellent halation protection and consequently yields high image sharpness.

[0004] Unfortunately, carbon black has the disadvantage of getting loose easily from the antihalation back layer, thus creating dust that smears the photographic elements and exerts a disturbing influence during the imagewise exposure thereof. Moreover, the removal of the carbon black antihalation back layer, which is to take place before the colour development can be started, is rather cumbersome.

[0005] To avoid the disadvantages concurrent with the use of carbon black antihalation back layers in photographic colour negative and colour intermediate film elements, one can make use of antihalation dyes in these elements in the same way as it is done in other types of photographic elements, in which one or several antihalation dyes having light absorption spectra depending on the spectral sensitivity of the light-sensitive layers are employed. It is for instance known to use in a panchromatic graphic arts material a combination of antihalation dyes, which absorb in the entire visible spectral range.

[0006] As far as photographic colour negative and colour intermediate film elements are concerned, reference can be found of the use of a blue antihalation layer between the transparent support and the red-sensitized emulsion layer(s). See e.g. the 1st column of page 389 of Neblette's Handbook of Photography and Reprography, 7th edition by John M. Sturge, Van Nostrand Reinhold Cy. New York.

[0007] However, this is rather theory since in practice no commercially available colour negative and colour intermediate film elements have so far been known to make use of a blue antihalation undercoat. All commercial film elements indeed make use of an above-mentioned carbon black antihalation back layer and have to take the disadvantages thereof into the bargain.

[0008] The reason why blue dyes have not been used hitherto in an antihalation undercoat of commercial films is that the light-absorbing dye or mixture of light-absorbing dyes that provides the desired absorption spectrum does not fully comply with the requirement of being non-diffusing towards other colloid layers. It is indeed experienced unfortunately that the blue dye or mixture of blue dyes that provide(s) the desired absorption spectrum, often is (are) not entirely fast to diffusion and as a consequence migrate(s) at least partially to the adjacent red-sensitized emulsion layer and may sensitize this emulsion layer to an unwanted part of the spectrum so that its sensitivity to red light is reduced.

[0009] Another problem linked with the use of dye in a blue antihalation undercoat, is that it is extremely difficult to find a dye or a combination of dyes that provide the desired absorption spectrum, while at the same time the dye(s) should comply with the necessity of being completely removable and/or decolourizable in at least one of the processing baths. Residual hue frequently remains after processing, which results in an increased minimum density.

[0010] Replacing the carbon black antihalation back layer by an antihalation dye back layer, in other words an antihalation layer on the side of the support opposite to that of the emulsion layers, would result in the advantage that the support, which constitutes a bar between said antihalation back layer and the red-sensitized emulsion layer(s), prevents the dye(s) from diffusing. However, this means that a dye-containing layer has to be coated on the rear side of the support, which may cause difficulties with respect to the antistatic properties of the film element. Moreover, a colour negative or colour intermediate film element carrying such a dye-containing back layer may have an increased tendency of sticking and be susceptible to scratching. Furthermore, the side of the support that is to carry the dye-containing layer may have to be subbed first with a supplemental coating to improve the adhesion.

[0011] It is therefore an object of the present invention to provide a photographic colour negative or a colour intermediate film element that does not suffer from the disadvantages of a carbon black antihalation back layer or of a dye-containing back layer but that still offers the advantage of yielding the high image sharpness achievable with a carbon black antihalation back layer.

[0012] This object can be accomplished according to the present invention by providing a photographic colour negative or colour intermediate film element comprising a transparent film support and coated thereon in succession, a blue antihalation layer, 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, a yellow filter layer, at least one blue-sensitive silver halide emulsion layer comprising at least one yellow-forming coupler, and an antistress layer, characterized in that said blue antihalation layer comprises at least one blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye in dispersed state in a hydrophilic colloid, said dye absorbing red light and being removable and/or decolourizable in a processing bath.

[0013] According to a preferred embodiment of the present invention said blue antihalation layer comprises at least one dispersed blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye corresponding to the general formula I :


in which:
each of R1 and R², which may be the same or different, represents:
   hydrogen, a C₁-C₄ alkyl group e.g. n-butyl, a substituted C₁-C₄ alkyl group, a C₁-C₄ alkoxy group, an aryl group e.g. phenyl, or a substituted aryl group such as phenyl substituted with at least one substituent chosen from the group consisting of a halogen atom, hydroxy, alkyl , alkoxy, carboxy, carbamoyl , sulphamoyl, alkoxycarbonyl, aryloxycarbonyl, alkoxysulphonyl, aryloxysulphonyl, and heterocyclylsulphonyl, e.g. o-sulphamoylphenyl, p-methoxyphenyl, and 3-hydroxy-4-carboxy-phenyl, 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 e.g. cyclohexyl.

[0014] In dissolved state the blue pentamethine oxonol-type barbituric acid derivative dyes absorb light of the spectral range between about 585 nm and about 605 nm, which as such is inappropriate for use as antihalation dye(s) in the blue antihalation layer. In dispersed state in gelatin, however, the absorption maximum of these dyes is found to be shifted bathochromically by at least 100 nm, which makes them highly suited for use as antihalation dye(s) in the blue antihalation layer. In dispersed state, they show a broad and fairly uniform absorption spectrum.

[0015] It has been established indeed that the image sharpness obtained with photographic colour negative and colour intermediate film elements of the present invention comprising a blue antihalation layer between the support and the red-sensitized emulsion layer(s), said blue antihalation layer being a hydrophilic colloid layer incorporating at least one blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye in dispersed state, equals the sharpness obtained with comparable known film elements comprising a carbon black antihalation back layer instead. This is due to the fact that any red light passing through the red-sensitized emulsion layer(s) is absorbed in the blue antihalation layer and is thus prevented from being reflected by the support and causing unsharp images in the red-sensitized emulsion layer(s).

[0016] The pentamethine oxonol-type barbituric acid derivative dyes meet the demands made on light-absorbing dyes for photographic silver halide elements. They are readily compatible with photographic binders such as e.g. gelatin and they can easily be incorporated into the photographic element. Moreover, they possess a high absorptive power. Below a pH-value of 7 they do not migrate in hydrophilic colloid layers and do not dissolve in water, whereas they dissolve readily in water above pH 7. Although during processing they decolour very quickly, even in rapid processing, they are very stable in coating compositions. Furthermore, they are discharged quickly, completely, and irreversibly in an alkaline processing solution, e.g. a developing solution, without forming coloured degradation products, so that there is no residual colour in the material after the processing, nor in the processing liquid.

[0017] The following Table 1 shows a non-restrictive list of representative examples of blue pentamethine oxonol-type barbituric acid derivatives corresponding to general formula I, which can be used according to the present invention. The symbols used in Table 1 refer to general formula I.

TABLE 1

Blue pentamethine oxonol-type barbituric acid derivative dyes
Dye N°	R¹ and R²	R³ and R⁴
B-01	hydrogen	p-methoxyphenyl
B-02	hydrogen	phenyl
B-03	hydrogen	n-hexyl
B-04	hydrogen	p-tolyl
B-05	hydrogen	n-octyl
B-06	hydrogen	p-chlorophenyl
B-07	hydrogen	o-tolyl
B-08	hydrogen	o-chlorophenyl
B-09	hydrogen	p-carboxyphenyl
B-10	hydrogen	5-carboxy-2-n-hexadecyloxyphenyl
B-11	n-butyl	2-hydroxyethyl
B-12	phenyl	2-hydroxyethyl
B-13	o-sulphamoylphenyl	cyclohexyl
B-14	3-hydroxy-4-carboxyphenyl	cyclohexyl
B-15	p-methoxyphenyl	cyclohexyl
B-16	p-methoxyphenyl	n-butyl

[0018] The blue dye B-01 can be prepared as described in Preparation 1 hereinafter.

PREPARATION 1

[0019] A volume of 5 l of dimethylformamide is brought in a 20 l open flanged vessel provided with a mechanical stirrer, a thermometer, a dropping funnel, and a cooling tub. An amount of 949 g (4 mol) of barbituric acid is added with stirring thereto at room temperature. After complete dissolution of the barbituric acid an amount of 569 g (2 mol) of glutaconaldehyde dianilide hydrochloride is added also at room temperature. A volume of 1680 ml of triethylamine is added dropwise at 20 - 30°C with cooling on a mixture of ice and water. The mixture is stirred for 15 min. A volume of 400 ml of acetic anhydride is added dropwise again at 20 - 30°C with cooling on a mixture of ice and water. Stirring is continued for 3 h at 20 - 30°C. The reaction mixture is poured out on 12 kg of ice, 12 l of a 25% aqueous solution of sodium chloride, and 1680 ml of hydrochloric acid. The mixture is stirred for 1 h, allowed to stand overnight, and centrifuged. The solid product is stirred for 30 min with 24 ml of hydrochloric acid in 24 l of water and then centrifuged. The product was dried in a drying cabinet at 70°C until dry.
Yield of dye B-01: (1,5-bis-[1-H-3-(p-methoxyphenyl)-barbituric acid]-pentamethine oxonol): 100%. Melting point: 215°C.

[0020] The other pentamethine oxonol-type barbituric acid derivative dyes for use in accordance with the present invention can be prepared analogously.

[0021] Dye B-01 was found to be particularly suited for use as blue antihalation dye according to the present invention in its ammonium salt form.

[0022] The absorption characteristics of the pentamethine oxonol-type barbituric acid derivative dyes of Table 1 are listed in the following Table 2. The values of absorption maximum given in Table 2 were measured in solution. In dissolved state these dyes absorb between about 585 and about 605 nm. In dispersed state in gelatin the absorption maximum was found to have shifted bathochromically by at least 100 nm.

TABLE 2

Dye no.	Absorption maximum (in nm)	ε x 10⁻⁵	measured in
B-01	590	1.28	methanol
B-02	590	1.29	methanol
B-03	588	1.52	methanol/triethylamine
B-04	598	1.65	dimethylformamide
B-05	590	9.21 x 10⁻⁴	methanol/triethylamine
B-06	598	1.57	dimethylformamide
B-07	596	1.63	dimethylformamide
B-08	598	1.55	dimethylformamide
B-09	602	1.05	dimethylformamide
B-10	598	1.58	dimethylformamide
B-11	590	1.10	methanol
B-12	590	1.27	methanol
B-13	596	1.33	methanol
B-14	596	1.01	methanol
B-15	594	1.10	methanol
B-16	594	1.03	methanol

[0023] According to another preferred embodiment of the present invention the yellow filter layer between the green-sensitized emulsion layer(s) and the blue-sensitive emulsion layer(s) is a hydrophilic colloid layer, usually a gelatin layer, comprising at least one dispersed yellow non-diffusing dye that absorbs blue light, is removable and/or decolourizable in a processing bath, and is chosen from the group consisting of :

• merostyryl dyes corresponding to the following general formula II:
  
  in which:

  R⁵

  represents hydrogen, a C₁-C₄ alkyl group e.g. methyl, isopropyl, butyl, a substituted C₁-C₄ alkyl group such as C₁-C₄ alkyl substituted with a halogen atom, hydroxy, carboxy, cyano e.g. trifluoroethyl, hydroxyethyl, carboxymethyl, cyanoethyl, an aryl group e.g. phenyl, a substituted aryl group e.g. tolyl, carboxyphenyl, dicarboxyphenyl, an aralkyl group, a substituted aralkyl group, or a heterocyclic group,

  R⁶

  represents one of the groups represented by R⁵, a carboxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an ureido group, or a sulphamoyl group, at least one of R⁵ and R⁶ being or containing a carboxy group or a carbamoyl group, and

  R⁷

  represents hydrogen, a C₁-C₄ alkyl group, or a C₁-C₄ alkoxy group e.g. methoxy, and when R⁷ is a C₁-C₄ alkyl group or a C₁-C₄ alkoxy group, it stands in ortho- or para-position in respect of the hydroxy group, which itself is in ortho- or para-position in respect of the methine group, and

• monomethine oxonol dyes corresponding to the general formula III :
  
  in which:
  each of R⁸ and R⁹, which may be the same or different, represents:
     hydrogen, a C₁-C₄ alkyl group e.g. t-butyl, a substituted C₁-C₄ alkyl group e.g. 2-trifluoroethyl, an aryl group e.g. phenyl, a substituted aryl group e.g. carboxyphenyl and dicarboxyphenyl, or a heterocyclic group e.g. 3-sulfolanyl,
  each of R¹⁰ and R¹¹, which may be the same or different, represents:
     a C₁-C₄ alkyl group e.g. methyl, a carboxy group, or a carbamoyl group,
  at least one of R⁸, R⁹, R¹⁰, and R¹¹ being or containing carboxy or carbamoyl.

[0024] The yellow merostyryl dyes corresponding to the above general formula II and the yellow monomethine oxonol dyes corresponding to the above general formula III are preferably used in dispersed state in a hydrophilic colloid, since in such state they also show a broad rather uniform absorption spectrum and are thus capable of absorbing any blue light not absorbed by the blue-sensitive emulsion layer(s).

[0025] The yellow merostyryl dyes of general formula II and monomethine oxonol dyes of general formula III also meet the demands made on light-absorbing dyes for photographic silver halide elements, which demands have been described already above for the blue pentamethine oxonol -type barbituric acid derivative dyes of general formula I.

[0026] The following Table 3 shows a non-restrictive list of representative examples of merostyryl dyes, which can be used according to an above-mentioned preferred embodiment of the present invention. The symbols refer to general formula II.

TABLE 3

Yellow merostyryl dyes
Dye N°	R⁵	R⁶	R⁷	Position of -OH
YM-01	p-carboxyphenyl	methyl	m-methoxy	para
YM-02	p-carboxyphenyl	methyl	m-methoxy	ortho
YM-03	p-carboxyphenyl	methyl	hydrogen	para
YM-04	p-carboxyphenyl	methyl	hydrogen	ortho
YM-05	p-carboxyphenyl	ethoxycarbonyl	hydrogen	para
YM-06	phenyl	carboxy	hydrogen	para
YM-07	trifluoroethyl	carbamoyl	hydrogen	para
YM-08	phenyl	carbomoyl	hydrogen	para

[0027] The merostyryl dyes can be prepared as described in US-A 4,311,787.

[0028] The absorption characteristics of the merostyryl dyes of Table 3 are listed in the following Table 4. The absorption maxima measured in a non-polar solvent (e.g. methanol) vary between about 380 and 440 nm, whereas in a mixture of a non-polar solvent and a base (e.g. triethylamine) or in a polar solvent (e.g. dimethylformamide) an absorption maximum shifted bathochromically by up to 100 nm is obtained. When measured in dispersed state in gelatin the absorption maximum of these merostyryl dyes was found to have shifted hypsochromically, the absorption spectrum being broader and more uniform, which is most advantageous for use according to an embodiment of the present invention.

TABLE 4

Dye no.	Absorption maximum (in nm)	ε x 10⁻⁴	measured in
YM-01	392	3.64	methanol
YM-02	434	2.67	methanol
YM-03	472	4.7	methanol/triethylamine
YM-04	384	1.55	methanol
YM-05	498	3.65	methanol/triethylamine
YM-06	482	2.89	methanol/triethylamine
YM-07	498	7.13	dimethylformamide
YM-08	498	5.89	dimethylformamide

[0029] Preferably, the dye 1-(p-carboxyphenyl)-3-methyl-4-(p-hydroxybenzylidene)-2-pyrazolin-5-one (YM-03) listed in Table 3 is used as merostyryl dye in dispersed state in the yellow filter layer, preferably a gelatin-containing filter layer, between the at least one green-sensitized emulsion layer and the at least one blue-sensitive emulsion layer.

[0030] The following Table 5 shows a non-restrictive list of representative examples of yellow monomethine oxonol dyes corresponding to general formula III, which can be used according to an above-mentioned preferred embodiment of the present invention. The symbols refer to general formula III.

TABLE 5

Yellow monomethine oxonol dyes
Dye N°	R⁴	R⁵	R⁶	R⁷
YO-01	phenyl	phenyl	carboxy	carboxy
YO-02	p-carboxyphenyl	p-carboxyphenyl	methyl	methyl
YO-03	t-butyl	t-butyl	carboxy	carboxy
YO-04	trifluoroethyl	trifluoroethyl	carboxy	carboxy
YO-05	3,5-dicarboxyphenyl	3,5-dicarboxyphenyl	methyl	methyl
YO-06	3-sulfolanyl	3-sulfolanyl	carbamoyl	carbamoyl

[0031] The yellow monomethine oxonol dyes corresponding to general formula III can be prepared according to methods known in the art; reference can be made in this respect to US-A 4,092,168, 4,266,014, and 4,288,534.

[0032] The absorption characteristics of the monomethine oxonol dyes of Table 5 are listed in the following Table 6.

TABLE 6

Dye no.	Absorption maximum (in nm)	ε x 10⁻⁴	measured in
YO-01	415	1.93	methanol
YO-02	410	2.72	methanol
YO-03	415	2.20	methanol
YO-04	415	2.30	methanol
YO-05	446	2.88	dimethylformamide
YO-06	480	2.20	dimethylformamide

[0033] According to an even more preferred embodiment of the present invention the dye B-01 listed in Table 1 is used in its ammonium salt form as pentamethine oxonol-type barbituric acid derivative dye in dispersed state in the gelatin-containing intermediate layer between the support and the at least one red-sensitized emulsion layer and the dye YM-03 listed in Table 3 is used as merostyryl dye in dispersed state in the yellow gelatin-containing filter layer between the at least one green-sensitized emulsion layer and the at least one blue-sensitive emulsion layer.

[0034] The blue pentamethine oxonol-type barbituric acid derivative dyes used in accordance with the present invention as well as the yellow merostyryl dyes according to general formula II and/or the monomethine oxonol dyes according to general formula III can be incorporated into hydrophilic colloid compositions according to any of the dispersion techniques known for incorporating water-insoluble colour couplers in hydrophilic colloid media.

[0035] According to the present invention it is preferred to prepare a dispersion of the blue pentamethine oxonol-type barbituric acid derivative dyes in an aqueous hydrophilic colloid composition by finely grinding the dyes in a mill e.g. a ball mill, a sand mill, or a colloid mill in the presence of one or more dispersing agents; the hydrophilic colloid e.g. gelatin is added after or before the milling process. The dispersion obtained can then be mixed with other ingredients to form a coating composition for the blue antihalation layer of the photographic colour negative or colour intermediate film element of the present invention.

[0036] Analogously, it is preferred to prepare a dispersion of the yellow merostyryl dyes of general formula II and/or monomethine oxonol dyes of general formula III in the same way. The dispersion obtained can also be mixed with other ingredients to form the coating composition for the yellow filter layer of the photographic colour negative or colour intermediate film element of the present invention.

[0037] 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.

[0038] 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, or polycarbonate.

[0039] 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-A 4,132,552.

[0040] According to a preferred embodiment of the present invention the side of the transparent film support of the photographic colour negative or colour intermediate film element, opposite to that carrying the emulsion layers is provided with an antistatic layer comprising an electroconductive polymer e.g. as described in US-A 4,089,997, preferably an antistatic layer comprising polystyrene sulphonic acid sodium salt. This antistatic layer may comprise polymer beads as described in EP-A 0,080,225, these beads protruding from the antistatic layer surface and consequently acting as spacing agents to reduce contact with adjacent surfaces.

[0041] The thickness of the blue antihalation 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 blue pentamethine oxonol-type barbituric acid derivative dye in the blue antihalation layer may vary from 750 mg to 10 mg per m2, preferably from 250 to 25 mg per m2.

[0042] The thickness of the yellow filter layer and the amount of the yellow dyes present therein are not critical either and they generally are chosen in the ranges described above for the blue antihalation layer.

[0043] The following examples illustrate the present invention.

EXAMPLE 1

[0044] A dispersion was made of the blue dye B-01 (in its ammonium salt form) in 2% aqueous gelatin by milling in a swinging mill with a concentration of 250 mg of dye per 100 g of dispersion.

[0045] A coating composition was made by adding gelatin and water, the resulting composition containing 5.4 g of the blue dye. The composition was coated on a subbed cellulose triacetate support in such a way that 2.5 g of gelatin and 270 mg of the dye were present per m2. The blue gelatin layer obtained was covered with a non-spectrally-sensitized silver chlorobromide emulsion layer comprising an amount of silver halide equivalent to 1.04 g of silver nitrate per m2.

[0046] The dye in the blue gelatin layer showed an excellent fastness to diffusion. No desensitization of the emulsion layer could be measured. Neither did the spectral sensitivity of the emulsion layer change, because the dye had not migrated at all into the emulsion layer and as a consequence could not have exerted any sensitizing effect on it.

[0047] During treatment of the resulting element with a common alkaline colour developing bath the blue dye decoloured completely in 1 to 2 min.

EXAMPLE 2

[0048] Samples of colour negative film elements A to C 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 position and composition of the antihalation layer(s), as explained hereinafter.

[0049] Element A additionally carried a carbon black antihalation layer on the rear side of the support, the carbon black layer having a thickness of 1 µm and comprising 250 mg of carbon black per m2.

[0050] Element B had no carbon black antihalation back layer, but instead 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.

[0051] Element C had no carbon black antihalation back layer, but instead had an identical blue antihalation layer as in Element B and in addition thereto comprised a yellow filter layer between the green-sensitized emulsion layer and the blue-sensitive emulsion layer, which filter layer comprised the yellow dye YM-03 in an amount of 200 mg per m2, the amount of gelatin being 1 g per m2.

[0052] Each of the samples A, B, and C was individually placed in contact with a transparent square wave chart or wedge and exposed to blue and red monochromatic light. After colour development, the values of speed and Modulation Transfer Function (MTF) were measured. These values are listed in the following Table 7.

[0053] The values given for the speed are relative values, a value of 100 being given to Element A having the carbon black layer, the value 200 corresponding to a doubling of the speed.

TABLE 7

Element	Speed	MTF value (%)
Red-sensitive layer		2	5	10	30	60	100 lines/mm
A exposed to red	100	114	111	93	57	24	17
B exposed to red	103	112	108	91	55	23	16
C exposed to red	105	110	105	85	50	20	15
Blue-sensitive layer		2	5	10	30	60	100 lines/mm
A exposed to blue	100	110	108	102	84	52	40
B exposed to blue	100	114	112	106	88	55	44
C exposed to blue	102	112	110	102	81	48	36

[0054] These results demonstrate that the image sharpness obtained in the red-sensitized emulsion layer of the film element C according to the present invention equals the image sharpness obtained in the red-sensitized emulsion layer of a comparable film element comprising a carbon black antihalation back layer. In spite of the presence of the blue antihalation layer in Element C the speed of the red-sensitized emulsion layer of Element C was comparable to that of the corresponding layer in Element A.

[0055] The image sharpness obtained in the blue-sensitive emulsion layer of the film element C equals the image sharpness obtained in the blue-sensitive emulsion layer of a comparable film element comprising a carbon black antihalation back layer.

Claims

1. Photographic colour negative or colour intermediate film element comprising a transparent film support and coated thereon in succession, a blue antihalation layer, 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, a yellow filter layer, at least one blue-sensitive silver halide emulsion layer comprising at least one yellow-forming coupler, and an antistress layer, wherein said blue antihalation layer comprises at least one blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye in dispersed state in a hydrophilic colloid, said dye absorbing red light and being removable and/or decolourizable in a processing bath.

2. A photographic colour negative or colour intermediate film element according to claim 1, wherein said blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye corresponds to the general formula I :

in which:
each of R¹ and R², which may be the same or different, represents:
   hydrogen, a C₁-C₄ alkyl group, a substituted C₁-C₄ alkyl group, a C₁-C₄ alkoxy group, an aryl group, or a substituted 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.

3. A photographic colour negative or colour intermediate film element according to claim 1 or 2, wherein said blue non-diffusing pentamethine oxonol-type barbituric acid derivative dye is the ammonium salt of (1,5-bis-[1-H-3-(p-methoxyphenyl)-barbituric acid]-pentamethine oxonol).

4. A photographic colour negative or colour intermediate film element according to any of the foregoing claims, wherein said yellow filter layer is a hydrophilic colloid layer comprising at least one dispersed yellow non-diffusing dye that absorbs blue light, is removable and/or decolourizable in a processing bath, and is chosen from the group consisting of :

- merostyryl dyes corresponding to the following general formula II:

in which:

R⁵   represents hydrogen, a C₁-C₄ alkyl group, a substituted C₁-C₄ alkyl group, an aryl group, a substituted aryl group, an aralkyl group, a substituted aralkyl group, or a heterocyclic group,

R⁶   represents one of the groups represented by R⁵, a carboxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an ureido group, or a sulphamoyl group, at least one of R⁵ and R⁶ being or containing a carboxy group or a carbamoyl group, and

R⁷   represents hydrogen, a C₁-C₄ alkyl group, or a C₁-C₄ alkoxy group, and when R⁷ is a C₁-C₄ alkyl group or a C₁-C₄ alkoxy group, it stands in ortho- or para-position in respect of the hydroxy group, which itself is in ortho- or para-position in respect of the methine group, and

- monomethine oxonol dyes corresponding to the general formula III :

in which:
each of R⁸ and R⁹, which may be the same or different, represents:
   hydrogen, a C₁-C₄ alkyl group, a substituted C₁-C₄ alkyl group, an aryl group, a substituted aryl group, or a heterocyclic group,
each of R¹⁰ and R¹¹, which may be the same or different, represents:
   a C₁-C₄ alkyl group, a carboxy group, or a carbamoyl group, at least one of R⁸, R⁹, R¹⁰, and R¹¹ being or containing carboxy or carbamoyl.

5. A photographic colour negative or colour intermediate film element according to claim 4, wherein said dispersed yellow non-diffusing dye is 1-(p-carboxyphenyl)-3-methyl-4-(p-hydroxybenzylidene)-2-pyrazolin-5-one (YM-03).

6. A photographic colour negative or colour intermediate film element according to any of the foregoing claims, wherein said hydrophilic colloid is gelatin.

7. A photographic colour negative or colour intermediate film element according to any of the foregoing claims, wherein the side of the transparent film support that is opposite to that carrying the emulsion layers is provided with an antistatic layer comprising an electroconductive polymer.

8. A photographic colour negative or colour intermediate film element according to any of the foregoing claims, wherein the side of the transparent film support that is opposite to that carrying the emulsion layers is provided with an antistatic layer comprising polystyrene sulphonic acid sodium salt.

9. A photographic colour negative or colour intermediate film element according to any of the claims 2 to 8, wherein the amount of the blue pentamethine oxonol-type barbituric acid derivative dye in the blue antihalation layer varies from 250 to 25 mg per m2.