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(11) | EP 0 329 491 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Photographic elements incorporating antihalation and/or acutance dyes |
| (57) Bleachable dyes for use in photographic and photothermographic silver halide emulsions
of the general formula:
in which: m+p=2, n is 0 or 1, s is 0 or 1, Z¹ and Z² independently represent the non-metallic atoms necessary to complete a heterocyclic nucleus of the type present in cyanine dyes and in addition contain a water solubilizing group such as sulphonate, carboxylate, etc., R¹ and R² independently represent alkyl or substituted alkyl, alkenyl, substituted alkenyl or aralkyl, each group containing not more than 20 carbon atoms. R³ and R⁴ independently represent a hydrogen atom or an alkyl, substituted alkyl, alkenyl or substituted alkenyl each of which groups contain not more than 10 carbon atoms. R⁵, R⁶, R⁷ and R⁸, which together may not contain more than 12 carbon atoms, independently represent a hydrogen atom, an alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl or alkaryl group, or one of R⁵ and R⁶ together with one of R⁷ and R⁸ represent the necessary atoms to complete a carbocyclic ring in which case the others of R⁵ to R⁸ are absent, Q¹ and Q² together represent the non-metallic atoms necessary to complete an acidic nucleus of the type present in oxonol or merocyanine dyes. |
[0001] This invention relates to a photographic element incorporating an antihalation or acutance dye.
[0002] Light sensitive recording materials may suffer from a phenomenon known as halation which causes degradation in the quality of the recorded image. Such degradation may occur when a fraction of the imaging light which strikes the photosensitive layer is not absorbed but passes through to the film base on which the photosensitive layer is coated. A portion of the light reaching the base may be reflected back to strike the photosensitive layer from the underside. Light thus reflected may, in some cases, contribute significantly to the total exposure of the photosensitive layer. Any particular matter in the photosensitive element may cause light passing through the element to be scattered. Scattered light which is reflected from the film base will, on its second passage through the photosensitive layer, cause exposure over an area adjacent to the point of intended exposure. It is this effect which leads to image degradation. Silver halide based photographic materials (including photothermographic materials) are prone to this form of image degradation since the photosensitive layers contain light scattering particles. The effect of light scatter on image quality is well documented and is described, for example, in T. H. James "The Theory of the Photographic Process", 4th Edition, Chapter 20, Macmillan 1977.
[0003] It is common practice to minimize the effects of light scatter by including a light absorbing layer within the photographic element. To be effective the absorption of this layer must be at the same wavelengths as the sensitivity of the photosensitive layer. In the case of imaging materials coated on transparent base, a light absorbing layer is frequently coated on the reverse side of the base from the photosensitive layer. Such a coating, known as an "antihalation layer", effectively prevents reflection of any light which has passed through the photosensitive layer.
[0004] A similar effect may be achieved by a light absorbing layer interposed between the photosensitive layer and the base. This construction, described as an "antihalation underlayer" is applicable to photosensitive coatings on transparent or non-transparent bases. A light absorbing substance may be incorporated into the photosensitive layer itself, in order to absorb scattered light. Substances used for this purpose are known as "acutance dyes". It is also possible to improve image quality by coating a light absorbing layer above the photosensitive layer of a wet processed photographic element. Coatings of this kind, described in U.S. Patent Specification No. 4,312,941 prevent multiple reflections of scattered light between the internal surfaces of a photographic element.
[0005] Many substances are known which absorb visible and/or ultraviolet light, that are suitable for image improvement purposes in conventional photographic elements sensitized to wavelengths below 700 nm. Triarylmethane and oxonol dyes in particular, are used extensively in this connection. There is, however, a need for antihalation and acutance dyes which absorb in the near infrared region of the spectrum. Dyes of this type are required for recording materials which are spectrally sensitized to near infrared wavelengths, for example, materials which are designed to record the output of near infrared lasers. Coatings of infrared absorbing pigments such as carbon black may be used. However, the use of this material is objectionable since it does not decolorise during processing and must therefore be coated in a binder which dissolves in developing solution allowing the carbon black to wash off causing objectionable contamination of the developer.
[0006] The classes or organic dyes which are commonly employed for antihalation and/or acutance purposes in ultraviolet and visible light sensitive materials do not readily form stable derivatives which absorb strongly in the near infrared. References to visible light herein refer to wavelengths between 400 and 700 nm and references to near infrared light refer to wavelengths between 700 and 1400 nm.
[0007] Coatings of antihalation or acutance dyes which absorb in the visible region of the spectrum are required to become colorless during processing of the photographic material, either by washing out or chemical reaction in wet processing techniques or thermal bleaching during heat processing techniques. Cyanine dyes are well known in the photographic art and are extensively used as spectral sensitizers for silver halide based materials. Cyanine dyes are not usually used or considered suitable for antihalation or acutance purposes owing to their limited solubility in aqueous media and especially to their inability to decolorise completely during photographic processing when present in large quantities.
[0008] It is an object of the invention to provide a class of dyes which are water soluble and are capable of producing coatings which absorb in the near infrared and become colorless during processing.
[0009] Therefore, according to the present invention there is provided a photographic element comprising one or more photosensitive layers and, as an antihalation or acutance dye, an antihalation or acutance effective amount of one or more compounds of the formula:
in which:
m+p=2, preferably m=p=1,
n is 0 or 1,
s is 0 or 1,
Z¹ and Z² independently represent the non-metallic atoms necessary to complete a heterocyclic nucleus of the type present in cyanine dyes and in addition contain a water solubilizing group such as sulphonate, carboxylate, etc.
[0010] R¹ and R² independently represent an alkyl, substituted alkyl, alkenyl, substituted alkenyl or aralkyl group of up to 20 carbon atoms,
R³ and R⁴ independently represent a hydrogen atom or an alkyl, substituted alkyl, alkenyl or substituted alkenyl group of up to 10 carbon atoms,
R⁵, R⁶, R⁷ and R⁸, which together may not contain more than 12 carbon atoms, independently represent a hydrogen atom, an alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl or alkaryl group, or
one of R⁵ and R⁶ together with one of R⁷ and R⁸ represent the necessary atoms to complete a carbocyclic ring (e.g. a benzene ring) in which case the others of R⁵ to R⁸ are absent,
[0011] Q¹ and Q² together represent the non-metallic atomsnecessary to complete an acidic nucleus of the type present in oxonol or merocyanine dyes.
[0012] The heterocyclic nuclei formed by Z¹ and Z² may be any of the wide range of nuclei known in the cyanine dye art. Generally, Z¹ and Z² each represent the non-metallic atoms necessary to complete a heterocyclic nucleus containing 5 to 6 atoms in the heterocyclic ring, the nucleus optionally possessing substituents. Preferably, the heterocyclic ring is composed of ring atoms selected form C, N, O, S and Se. Examples of such heterocyclic nuclei include:
the thiazole series, e.g. thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4-(2-thienyl)-thiazole,
the benzothiazole series, e.g. benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 6-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole,
the naphthothiazole series, e.g. naphtho[1,2]-thiazole, naphtho[2,1]thiazole, 5-methoxynaphtho-[2,1]-thiazole, 5-ethoxynaphtho[2,1]thiazole, 8-methoxynaphtho[1,2]thiazole, 7-methoxynaphtho[1,2]thiazole,
the thianaphtheno-7′,6′,4,5-thiazole series, e.g. 4′-methoxythianaphtheno-7′,6′,4,5,-thiazole,
the oxazole series, e.g. 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole,
the benzoxazole series, e.g. benzoxazole, 5-chlorobenzoxasole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,5-dimethylbenzoxazole, 5-methoxybenzoxazole, 5-ethoxybenzoxazole, 5-chlorobenzoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole,
the naphthoxazole series, e.g. naphtho[1,2]oxazole, naphtho[2,1]oxazole,
the selenazole series, e.g. 4-methylselenazole, 4-phenylselenazole,
the benzoselenazole series, e.g. benzoselenazole, 5-chlorobenzoselenazole, 5-methylbenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole,
the naphthoselenazole series, e.g. naphtho[1,2]-selenazole, naphtho[2,1]selenazole,
the thiazoline series, e.g. thiazoline, 4-methylthiazoline,
the 2-quinoline series, e.g. quinoline, 3-methylquinoline, 5-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxy-quinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroquinoline,
the 4-quinoline series, e.g. quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-methylquinoline,
the 1-isoquinoline series, e.g. isoquinoline, 3,4-dihydroisoquinoline,
the 3-isoquinoline series, e.g. isoquinoline,
the benzimidazole series, e.g. 1,3-diethylbenzimidazole, 1-ethyl-3-phenylbenzimidazole,
the 3,3-dialkylindolenine series, e.g. 3,3-dimethylindolenine, 3,3,5-trimethylindolenine, 3,3,7-trimethylindolenine,
the 2-pyridine series, e.g. pyridine, 5-methylpyridine, and
the 4-pyridine series, e.g. pyridine.
[0014] Preferably the groups R¹ and R² contain less than 8 carbon atoms. More preferably R¹ and R² are lower alkyl groups containing up to 4 carbon atoms. The alkyl groups may contain any substituent which does not deleteriously effect the properties of the dye as known in the cyanine art. Suitable substituted alkyl groups include alkoxy-alkyl, benzyl and carboxy-alkyl.
[0015] Preferably R³ and R⁴ represent a hydrogen atom or a lower alkyl group containing 1 to 4 carbon atoms.
[0016] Preferably R⁵ to R⁸ are hydrogen. However, certain substituted cyclopentanones are commercially available which may be used as intermediates in the preparation of the dyes of formula (I), e.g. 3-methyl-cyclopentanone and 3-phenylcyclopentanone and accordingly one of R⁵ to R⁸ may readily represent these substituents.
[0017] The cyclic acid nuclei completed by the groups Q¹ and Q² preferably have the ring atoms selected from C, S, N, O and Se. Suitable moieties are derived from the following nuclei which may additionally possess substituents: 1,3-indandione, pyrazolone, isoxazolone, e.g. 3-phenylisoxazolone, oxindole, 2,4,6-trioxohexahydropyrimidine, 2-thio-4,6-dioxohexahydropyrimidine, 3,5-pyrazolidinedione, 2(3H)-imidazole[1,2-a]pyridone, 5,7-dioxo-6,7-dihydro-5-thiazolo[3,2-a]pyrimidine, 2-thio-2,4-oxazolidinedione, thianaphthenonedioxide, 2-thio-2,4-thiazolidinedione, 2,4-thiazolidinedione, thiazolidione, 4-thiazolinone, 2-imino-2,4-oxazolinone, 2,4-imidazolinedione, 2-thio-2,4-imidazolinedione, 5,5-dialkyl-1,3-cyclohexanedione including 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and isopropylidine malonate (Meldrum's acid).
[0018] A preferred cyclic nucleus completed by Q¹ and Q² has the general formula:
in which:
R⁹ and R¹⁰ independently represent a hydrogen atom, an alkyl or cycloalkyl gruop which may be substituted, e.g. hydroxyalkyl, alkoxy-alkyl, alkoxycarbonyl, polyoxyalkyl; alkenyl or substituted alkenyl, an aryl group which may be substituted, or an aralkyl group, any of which groups may contain up to 25 carbon atoms. Preferably R⁹ and R¹⁰ together contain at least 8 carbon atoms and are aliphatic groups, more preferably at least one of R⁹ and R¹⁰· represents an alkyl group containing at least 8 carbon atoms.
[0019] The dyes of formula (I) absorb in the near infrared having a very low visible absorption whilst retaining a high extinction coefficient at the absorption maximum. In general, the dyes of the invention have extinction coefficients at their maximum absorption wavelength (typically 800 nm or higher) of the order of 2.5 x 10⁵ to 3.0 x 10⁵. However, at 700 nm the absorption has generally fallen to approximately 10% of this value and at 650 nm the absorption is down to approximately 2% of the value, as measured in methanolic solution.
[0020] The dyes may be incorporated into wet processed photographic or photothermographic elements as actuance dyes according to conventional techniques. The dyes may also be incorporated into antihalation layers according to techniques of the prior art, for example, in the case of wet processed photographic elements, as an antihalation backing layer, an antihalation underlayer or as an overcoat. It is also anticipated that similar nonamethine dyes would be suitable for use as actuance and antihalation dyes.
Distinguishing From the Prior Art
[0021] The present invention describes the preparation and use of water soluble, holopolar dyes as a non-stining antihalation system for near infrared recording media.
[0022] Dyes similar to formula (I) are known without the ring, water solubilizing groups. A class of dyes is disclosed in U.S. Patent Specification No. 2,955,939 for the sensitization of silver halide emulsions and in U.S. Patent 4,581,325 for use as antihalation dyes. U.S. Patent 3,194,805 discloses a class of merocyanine and holopolar dyes containing arylene-chain substitution and their use as spectral sensitizing dyes.
[0023] The minimum amount of a dye of formula (I) for use for acutance purposes greatly exceeds the maximum amount of dye used for sensitising purposes. For example, the quantity of sensitising dye used in the emulsions disclosed in U.S. Patent Specification No. 2,955,939 is in the general range 5 to 100, usually 10 to 20 mg per liter of emulsion whereas for acutance purposes in accordance with the invention the dyes would generally be used in the range 200 to 1000 mg per liter of emulsion.
[0024] U.S. 2,895,955. Heseltine et al. describes tricarbocyanine dyes containing a benzoindole nucleus which absorb in the near infrared (Compound E in this patent).
[0025] U.S. 3,148,187. Heseltine, describes a direct nuclear sulforation process for cyaine and merocyanine dyes.
[0026] U.S. 3,573,921. Jenkins et al., describes polynuclear sensitizing dyes prepared from certain 3,5-pyrazolidinedione compounds.
[0027] U.S. 3,637,676. Heseltine et al., describes polymethine dyes containing a dilactone ring. The dyes can be used as optical sensitizers or as filter dyes.
[0028] U.S. 3,573,921 described merocyanine dyes such as the 1,2-diphenyl-3,5-pyrazolidinedione in Example 1. There is no mention (even in the broad disclosure) of ring substitution with SOϑ₃. Sensitizing dyes only are described which are added to AgX emulsions.
[0029] U.S. 2,955,939 - holopolar dyes as sensitizers. Cover tri, penta and heptamethine dyes in examples. Examples cover different middle rings such as barbituric acid, 2-thiobarbaturic, rhodanine, thianaphthenone-1,1-dioxide, isoxazolone, and pyrazolone.
[0030] U.S. 4,256,819 - holopolar dyes for electrophoretic migration imaging processes. The dyes are similar to those of U.S. 2,955,939. No sulfonated versions are disclosed.
[0031] U.S. 3,194,805 describes merocyanine and holopolar dyes containing arylene-chain substitution.
[0033] The synthesis of dyes of the present invention represented by formula (I) involves the following stages:
(1) Ring sulphonation of a heterocyclic compound.
(2) Preparation of the ammonium salt of the sulphonated heterocycle.
(3) Condensation of an α-ketomethylene compound with a cyclopentanone.
(4) Reaction of ethylisoformanilide with the product of the condensation in step 3.
(5) Preparation of the dye of formula (1).
2(A) + (C) → Dye of Formula (1).
[0034] Table I contains the dyes of formula (I) which have been prepared and also other classes of dyes for comparison. Also included are references for the preparation of these compounds. The structures of the dyes are listed below.
Example 1
Preparation of Dye #2
a) Preparation of 2-methyl-6-sulfobenzthiazole
[0036] 2-methylbenzthiazole (60 g, 0.4 mole) was placed in a 250 ml round bottom flask fitted with a stirring bar, thermometer, condenser, and heating mantle. While stirring, 100 ml of concentrated sulfuric acid was added with subsequent temperature rise to 80°C. Oleum (80 ml, 30%) was added over a two minute period with the temperature rising to 115°C and formation of a dark solution. Ferric chloride (0.3 g) was added to the reaction heated to 200°C for one hour. The reaction was cooled to 50°C and poured into 6 liters of cool (10°C) acetone with good stirring. The resulting slurry was stirred for 15 minutes. The agitation was turned off and the acetone decanted from the solids. The procedure was repeated with 2 liters of acetone and the resulting slurry was filtered and rinsed with acetone. Recovered 63 g (68.5%). The solids were slurried with 300 ml of methanol and heated to reflux for 15 minutes. The slurry was cooled to 10°C, filtered and dried. Recovered 50 g, 54.3% yield.
b) Preparation of the sodium salt of 2-methyl-6-sulfobenzthiazole.
[0037] Placed 45 g (0.196 mole) of 2-methyl-6-sulfobenzthiazole in a 2 liter beaker equipped with a magnetic stirring bar. To the beaker was added 1 liter of methanol with constant stirring. Sodium bicarbonate (49 g) was added over the next 20 minutes, and the mixture was then stirred an additional 25 minutes. Nearly all the benzthiazole had dissolved after 30 minutes. The temperature at the end of the addition was 50°C with a final pH of 10.0. Anhydrous magnesium sulfate (20 g) was added and stirred for 15 minutes. The slurry was filtered and the solids rinsed with methanol. The filtrate was stripped of methanol on a rotary evaporator and the resulting solids dried at 70°C in vacuum. Recovered 48 g; a 97.6% yield.
c) Preparation of the sodium salt of 2-methyl-3-ethyl-6-sulfobenzthiazolium tosylate.
[0038] The sodium salt of 2-methyl-6-sulfobenzthiazole (40 g, 0.159 mole) was placed in a 500 ml flask equipped with a mechanical stirrer, thermometer, condenser, and a heating mantle. Ethyl-p-toluenesulfonate (169 g, 0.845 mole) and 7 ml of dimethylformamide were added with stirring and the mixture was heated to 175°C for three hours. 2,6-dimethyl-4-heptanone (25 ml) was added to aid stirring, and the mass was cooled to 60°C. The thick fluid was poured into 250 ml of well stirred acetone to precipitate the product. The slurry was cooled, filtered and dried at 80°C for two hours. Recovered 61.5 g; an 85.6% yield.
d) Preparation of ethylisoformanilide
[0039] Aniline (180 g, 1.94 mole) and triethylorthoformate (300 g, 2.02 mole) were placed in a one liter flask equipped with a mechanical stirrer, vigreux column, distillation head, thermometer, condenser, and a heating mantle. The reaction was heated to reflux (120°C) and 250 ml of distillate was removed over 60 minutes. To the dark solution, 75 ml of triethylorthoformate was added while continuing to heat at reflux. Distilled off 75 ml of liquid over six hours with the reaction temperature reaching 210°C. Cooled to 25°C, added 300 ml of hexane, stirred for 15 minutes and filtered. The resulting filtrate was distilled with the main cut distilling at 78-82°C/2mm. IR matches reference.
e) Preparation of 5-cyclopentylidene-1,3-dimethylbarbituric acid
[0040] A mixture of N,N-dimethylbarbituric acid (15.6 g, 0.1 mole), cyclopentanone (8.4 g, 0.01 mole), ammonium acetate (2.3 g, 0.04 mole), acetic acid (4 ml), and a chloroform (100 ml) were added with stirring into a 250 ml flask fitted with a stirrer, Barrett trap, condenser, and heating mantle. The mixture was heated to reflux for six hours, and 2 ml of water was removed by azeotropic distillation. The reaction was cooled, washed 3 times with 35 ml portions of water. The organic phase was heated at 60°C under reduced pressure to remove solvents. The resulting solids were recrystallized from 125 ml of anhydrous ethanol, cooled to 0°C, filtered and rinsed with cold ethanol. Recovered 12.5 g, (56.3%); m.p. 110-112°C.
f) Preparation of 5-(2,5-dianilinomethylenecyclopentylidene)-1,3-dimethylbarbituric acid.
[0041] A mixture of 5-cyclopentylidene-1,3-dimethylbarbituric acid (11.1 g, 0.05 mole) and ethylisoformanilide (17.9 g, 0.12 mole), and 35 ml of dimethylformamide were placed in a 100 ml flask fitted with a thermometer, magnetic stirrer, condenser, and heating mantle. The mixture was heated with stirring to 145°C for 5 minutes. The reaction was cooled to 20°C, and 50 ml of methanol were added. The mixture was then stirred with cooling for 10 minutes, filtered and rinsed on the filter with methanol. The solids were slurried twice with water, and then twice with methanol, filtering between each slurry. The solids were dried for 3 hr at 80°C. Recovered 8.0 g (40.3%), m.p. >250°C; λmax (MeOH) 545 nm.
g) Preparation of Dye #2
[0042] The sodium salt of 2-methyl-3-ethyl-6-sulfobenzthiazolium tosylate (4.51 g, 0.01 mole), and 5-(2-5-dianilinomethylenecyclopentylidene)-1,3-dimethylbarbituric acid (1.98 g, 0.005 mole), 20 ml of dimethylformamide, and 3 ml of triethylamine were mixed together in a 100 ml flask fitted with a thermometer, stirrer, reflux condenser and oil bath. The mixture was heated to 100°C with stirring for 5 minutes. The reaction mixture was poured into 200 ml of hexane with vigorous stirring. Stirring was continued for 10 minutes, and the hexane was decanted from the oil. The hexane treatment was repeated. Acetone (300 ml) was added to the oil and the mixture was stirred for 15 minutes. The resulting solids were filtered and washed well with acetone. Dried and recovered 4.5 g (87.5%); λmax (MeOH) 817 nm.
Example 2
[0043] Evaluation of the dyes was performed by coating an antihalation backing layer containing the dyes on 7 mil polyester base. Each dye was dissolved in water and added to an aqueous solution of gelatin at 40°C. A surfactant and formaldehyde (4.3 ml, 4%) were also added. THe final solution was at 5% gelatin. The dye-gelatin mixture was coated at 65 ml/m² onto subbed polyester base and dried. The characteristics of the AH coatings are reported in Table II.
[0044] The results listed in Table II show that the water soluble holopolar dyes (Ex. 1-4) offer particular advantages over water soluble cyanine dyes (A-D). The water soluble cyanine dye E does give a strong near infrared absorbing coating but has the drawback of high stain after automatic processing. The cyanine dyes, A-D, had strong maximum absorbance from 760-810 nm in methanol. However, when these dyes were added to water and coated as a gelatin solution, the absorbance curves shifted to lower wavelengths.
TABLE II
| Dye No. | Dye (g/L AH) | Density of Coating at 820 nm | Density of Coating at Absorption max | Wavelength of Absorption max of coating (nm) |
| 1 | 0.86 | 0.22 | 0.26 | 840 |
| 2 | 0.64 | 0.31 | 0.39 | 840 |
| 3 | 0.64 | 0.25 | 0.29 | 840 |
| 4 | 0.64 | 0.24 | 0.30 | 840 |
| A | 0.64 | 0.03 | -- | -- |
| B | 0.64 | 0.05 | -- | -- |
| C | 0.64 | 0.06 | -- | -- |
| D | 0.64 | 0.09 | -- | -- |
| E | 0.35 | 0.38 | 0.44 | 800 |
Example 3
[0045] The effects of automatic processing were evaluated on the AH, dye coatings to decide whether an acceptable stain level was achieved. Processing was performed in 90 seconds by a Kodak SP processor using Kodak X-Omat developer and fix. The 820 nm absorbance was read after processing example 1-4 and E and the stain level evaluated. Coatings 2-4 showed an increase in stain after processing of less than 0.01 visual density. The two unacceptable stains were example 1 with a light blue cast and E with a heavier, green-yellow stain. The results are listed in Table III.
TABLE III
| Dye No. | Dye G/L AH | 820 nm Abs. before Processing* | Processed* 820 nm Abs. | Stain after Processing |
| 1 | 0.86 | 0.22 | 0.04 | Unacceptable |
| 2 | 0.64 | 0.31 | 0.01 | No color |
| 3 | 0.64 | 0.25 | 0.01 | No color |
| 4 | 0.64 | 0.24 | 0.02 | Borderline |
| E | 0.35 | 0.38 | 0.21 | Unacceptable |
| * minus base density |
Example 4
[0046] An emulsion was prepared by a double jet precipitation having 64% chloride and 36% bromide with an average grain size of 0.24 micrometers. The emulsion was digested with p-toluenesulfinic acid, sodium thiosulfate and sodium gold tetrachloride (NaAuCl₄).
[0047] Final preparation of the emulsions comprised the addition of water and gelatin to a level of 5.0% gelatin and 2500 g of emulsion per mole of silver. The pH was adjusted to 7.0, and the pAg was adjusted to 7.2. Infrared sensitizing dye (F) was added in methanol at 30 mg/mole Ag. Phenyl-5-mercaptotetrazole in methanol (115 mg/mole Ag), poly(ethylacrylate) (30 g/mole Ag), formaldehyde hardener and surfactant were also added before coating. The material was coated at 2.4 g Ag/m².
[0048] The emulsion was coated on
(1) clear polyester base
(2) polyester base coated on the reverse side with Dye 2 in gelatin as in Example 2.
[0049] These coatings were evaluated by imaging with an 820 nm laser diode incorporated in a 3M Laser Imager. An SMPTE test target was printed on both followed by automatic X-ray processing. The unbacked Sample 1 showed heavy halation whereas Sample 2 diminished halation to an acceptable level.
[0050] A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.
1. A photographic element comprising one or more silver halide photosensitive layers
on a substrate, characterized in that the element includes in at least one layer free
of silver halide as an antihalation dye, an antihalation effective amount of at least
one compound that will provide a transmissive optical density of greater than 0.1
at the λmax of the compound, said compound having the formula:
in which:
m+p=2,
n is 0 or 1,
s is 0 or 1,
Z¹ and Z² independently represent the non-metallic atoms necessary to complete a heterocyclic nucleus of the type present in cyanine dyes and in addition contain a water solubilizing group such as sulphonate, carboxylate, etc.,
R¹ and R² independently selected from the group consisting of alkyl or substituted alkyl, alkenyl, substituted alkenyl or aralkyl, each group containing not more than 20 carbon atoms,
R³ and R⁴ independently selected from the group consisting of a hydrogen atom or an alkyl, substituted alkyl, alkenyl or substituted alkenyl each of which groups contain not more than 10 carbon atoms,
R⁵, R⁶, R⁷ and R⁸, which together may not contain more than 12 carbon atoms, are independently selected from the group consisting of a hydrogen atom, an alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl or alkaryl group, or
one of R⁵ and R⁶ together with one of R⁷ and R⁸ represent the necessary atoms to complete a carbocyclic ring in which case the others of R⁵ to R⁸ are absent,
Q¹ and Q² together represent the non-metallic atoms necessary to complete an acidic nucleus of the type present in oxonol or merocyanine dyes.
in which:
m+p=2,
n is 0 or 1,
s is 0 or 1,
Z¹ and Z² independently represent the non-metallic atoms necessary to complete a heterocyclic nucleus of the type present in cyanine dyes and in addition contain a water solubilizing group such as sulphonate, carboxylate, etc.,
R¹ and R² independently selected from the group consisting of alkyl or substituted alkyl, alkenyl, substituted alkenyl or aralkyl, each group containing not more than 20 carbon atoms,
R³ and R⁴ independently selected from the group consisting of a hydrogen atom or an alkyl, substituted alkyl, alkenyl or substituted alkenyl each of which groups contain not more than 10 carbon atoms,
R⁵, R⁶, R⁷ and R⁸, which together may not contain more than 12 carbon atoms, are independently selected from the group consisting of a hydrogen atom, an alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl or alkaryl group, or
one of R⁵ and R⁶ together with one of R⁷ and R⁸ represent the necessary atoms to complete a carbocyclic ring in which case the others of R⁵ to R⁸ are absent,
Q¹ and Q² together represent the non-metallic atoms necessary to complete an acidic nucleus of the type present in oxonol or merocyanine dyes.
2. A photographic element as claimed in claim 1, characterized in that Z¹ and Z² complete
a 5 or 6 membered heterocyclic nucleus which may possess substituents.
3. A photographic element as claimed in claim 2, characterized in that Z¹ and/or Z²
complete a heterocyclic nucleus selected from the group consisting of thiazole, benzothiazole,
naphthothiazole, thianaphtheno-7′6′4,5-thiazole, oxazole, benzoxazole, naphthoxazole,
selenazole, benzoselenazole, naphthoselenazole, thiazoline, 2-quinoline, 4-quinoline,
1-isoquinoline, 3-isoquinoline, benzimidazole, 3,3-dialkylindolenine, 2-pyridine,
and 4-pyridine, each of which nuclei may be substituted.
4. A photographic element as claimed in claim 1, characterized in that Z¹ and/or Z²
complete a benzothiazole or a 3,3-dialkylindolenine nucleus containing 3,3-dialkylindolenine
a water solubilizing group.
5. A photographic element as claimed in claim 1, characterized in that Q¹ and Q² complete
a moiety which is a derivative of one of the nuclei which may optionally possess substituents
selected from the group consisting of indandione, pyrazolone, isoxazolone, oxindole,
2,4,6-trioxohexahydropyrimidine, 2-thio-4,6-dioxohexahydropyrimidine, 3,5-pyrazolidinedione,
2(3H)-imidazo[1,2-a]pyridone, 5,7-dioxo-6,7-dihydro-5-thiazolo[3,2-a]pyrimidine, 2-thio-2,4-oxazolidinedione,
thianaphthenone dioxide, 2-thio-2,4-thiazolidindione, 4-thiazolinone, 2-imino-2,4-oxazolinone,
2,4-imidazolinedione, 2-thio-2,4-imindazolinedione cyclic groups, 5,5-dialkyl-1,3-cyclohexanedione
or isopropylidine malonate.
6. A photographic element as claimed in claim 5, characterized in that the moiety
completed by Q¹ and Q² contains at least one aliphatic or predominantly aliphatic
group.
7. A photographic element as claimed in claim 6, characterized in that Q¹ and Q² complete
a moiety of the general formula:
in which
R⁹ and R¹⁰ are independently selected from the group consisting of a hydrogen atom, an alkyl group which may be substituted, alkenyl, substituted alkenyl, an aryl group which may be substituted or an aralkyl group, each of which groups contain not more than 25 carbon atoms.
in which
R⁹ and R¹⁰ are independently selected from the group consisting of a hydrogen atom, an alkyl group which may be substituted, alkenyl, substituted alkenyl, an aryl group which may be substituted or an aralkyl group, each of which groups contain not more than 25 carbon atoms.
8. A photographic element as claimed in claim 5, characterized in that the photographic
element is a conventional wet processed photographic element.
A photographic element as claimed in claim 5, characterized in that the photographic
element is a photothermographic element comprising a silver halide photothermographic
element.
10. A photographic element as claimed in claim 5, characterized in that the dye of
formula (I) is present in an antihalation backing on said substrate, as an underlayer
between said substrate and said one or more photosensitive layers, in an overcoat
above the photosensitive layer, or in the photosensitive layer.