|
(11) | EP 0 329 335 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||||||
| (54) | Pattern free lithographic elements |
| (57) High contrast, hydrazine containing photographic elements are provided with additives
that reduce uneven development patterns in the final image. Surfactant is added to
a topcoat layer and/or an auxiliary developer is added to a silver halide emulsion
layer. |
FIELD OF INVENTION
[0001] This invention relates to photographic elements, particularly to very high contrast photographic elements, and more particularly to reduction of non-uniform development in rapid access processing of such high contrast photographic elements.
BACKGROUND OF INVENTION
[0002] The use of hydrazines in photograhic emulsions or developer baths to produce high contrast lithographic images has been known for many years and originally was disclosed in U.S. Patent 2,419,975. That photographic system required very high pH levels for development and the developer baths were short-lived and aerially unstable.
[0003] U.S. Patent 4,269,929 discloses the use of high sulfite content in developer solutions comprising a mixture of developers and alkanol amines with improved hydrazides in the emulsion which can be used at more intermediate pH ranges (e.g., 10.5 to 12.3) to produce high contrast, black-and-white, lithographic images.
[0004] U.S. Patent 4,560,638 discloses the use of unballasted arylhydrazides which are particularly useful in providing improved dot quality and reduced pepper fog in halftone, high contrast images. It is incidently disclosed that the emulsion may contain developing agents (col. 11, line 64- col. 12, line 8).
[0005] U.S. Patent 4,618,574 describes additives for high contrast arylhydrazide silver halide emulsions which can reduce pepper fog. There is again an incidential disclosure of the use of developing agents in the silver halide emulsion (col. 14, lines 6-19).
[0006] European patent application EP 155,690 and U.S. Patent 4,693,956 teach the use of alcohols and carbonols as contrast promoting agents for use with hydrazide-containing, high contrast silver halide photographic emulsions.
[0007] U.S. Patents Application Serial No. 10707, filed February 4, 1986, teaches the use of contrast promoting agents in the photographic emulsions prior to imagewise exposure in high contrast, hydrazide-containing silver halide photographic emulsions. This was reported to be able to further reduce necessary pH levels in the developer baths.
[0008] U.S. Patent 4,221,857 discloses the use of polyalkylene oxides having molecular weights of at least about 600 in high contrast, hydrazide containing silver halide emulsions or developer solutions in order to improve dot quality in half-tone images. One example of a useful additive is
High contast, rapid access lith films are particularly susceptible to randomly uneven densities across the imaged and processed photographic sheet. This defect is especially prominent in the low density, screened 70% tint exposures from halftone generating screens or electronic scanners. The defect ranges from uneven density across the sheet to random streaks down the entire sheet producing somewhat of a woodgrain appearance referred to herein as a swirl pattern.
[0009] The uneven density is primarily produced in, but not limited to, automatic processors. The complexity of this problem is that automatic processors do not produce this defect pattern on a regular basis. Each type of processor can produce its own type of defect pattern. These patterns include a type of edge pattern caused by the flow or circulation of developer in the developer tank section, a nip roller entry pattern occurring along the circumference of the rollers, and long random patterns along the length of the sheet of processed film. The latter is the most significant problem and is believed to be in part caused by bubble entrapment between the processing film path paired rollers.
[0010] This type of defect pattern, which is observed in many different commercially available films, renders the finished product useless in the quality trade shops.
[0011] These types of artifact problems are believed to be inherent to the use of hydrazide and their interactions with the developer environment. The use of a ballasted hydrazide tends to reduce the problem somewhat, but sacrifices photographic speed, since the ballasting of the hydrazide reduces it reactivity and increases processing times. No known disclosures are available on the appearance or solution of this type of problem.
SUMMARY OF THE INVENTION
[0012] It has been found that the addition of certain ingredients into the coating layers, singly, or in combination, producing a synergistic effect, alters the induction time for the processing of the hydrazine (hydrazide) containing photographic element. Particularly the addition of phenidone type developers (3-pyrazolidinone developers, particularly 1-phenyl-3-pyrazolidinone developers) and 2-pyrazoline type developers, particularly 1-phenyl-2-pyrazoline developers to the emulsion layer and the surfactant classes of alkoxylated alcohols and fluorinated surfactants to the topcoat layer has been found to reduce swirl patterns. It is believed tht these additives initiate sufficient development in the photographic elements prior to any adversely influential mechanical processing forces yielding uniform density films and art work.
[0013] This technology, especially when applied to high speed formulations, surprisingly produces practically defect free material in the very sensitive lower density screened tint exposure areas.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The addition of a swirl pattern reducing effective amount of a silver halide development accelerators comprising a 3-pyrazolidinone or 2-pyrazoline developer and/or high concentrations of surface active agents from the class of alkoxylated alcohols of molecular weight less than 1000 and fluorinated surfactants into the coating layers of a high contrast, hydrazide containing silver halide photographic emulsion reduces non-uniform development of the high contrast film, particularly for high speed, unballasted or shorter chain ballasted hydrazide containing emulsions.
[0015] The silver halide emulsions for use in the present invention may be silver chloride, silver chlorobromide, silver iodobromide, silver iodochloride, silver iodochlorobromide or any mixture of thereof. Generally, the iodide content of the silver halide emulsions is less than about 10% silver iodide, said content being based on the total silver halide. The silver halide emulsions are usually mondispersed or narrow grain size distribution emulsions, as described for example in U.S. Patent Specifications, 4,166,742; 4,168,977; 4,224,401; 4,237,214; 4,241,164; 4,272,614; and 4,311,871. The silver halide emusions may comprise a mixture of emulsions having different grain combinations, for example, a combination of an emulsion having a mean grain size below 0.4 microns with an emulsions have a mean grain size above 0.7 microns, as described in Japanese Patent Application S.N. 57-58137 or a combination of two emulsions, both having a grain size below 0.4 microns, such as for example a first silver halide emulsion having a mean grain size from 0.1 to 0.4 microns and a second silver halide emulsion with particles having a mean grain volume lower than one half the particles of the first emulsion as described in U.S. Patent Application Serial No. 881,081, filed July 2, 1986.
[0016] The silver halide grains of the emulsions of the present invention are capable of forming a surface latent image, as opposed to those emulsions forming an internal latent image. Surface latent image-forming silver halide grains are most usually employed in negative type silver halide emulsions, while internal latent latent image-forming silver halide grains, though capable of forming a negative image when developed in an internal developer, are usually employed with surface developers to form direct-positive images. The distinction between surface latent image and internal latent image-forming silver halide grains is well-known in the art. Generally, some additional ingredients or steps are required in the preparation of silver halide grains capable of preferentially forming an internal latent image instead of a surface latent image.
[0017] In the silver halide emulsions of the present invention, the precipitation or the growth of the silver halide grains optionally may be carried out in the presence of metal salts or complex salts thereof, such as rhodium and iridium salts or complex salts thereof. According to the present invention, the presence of rhodium or iridium is not necessary to obtain the high contrasts. Silver halide grains free of rhodium or iridium, as well as those formed or ripened in the presence of rhodium or iridium may be used in the present invention.
[0018] The silver halide emulsions of the present invention need not be chemically sensitized, but are preferably chemically sensitized. As chemical sensitization methods of silver halide emulsions, the known sulfur sensitization employing sulfur compounds, the reduction sensitization employing mild reducing agents and the noble metal sensitization can be used, either alone or in combination.
[0019] The silver halide emulsions can be spectrally sensitized with any spectral sensitizing dyes from a variety of classes, including the polymethine dye class, such as cyanines, merocyanines, complex cyanines and the complex merocyanines (i.e., tri-, tetra-, and poly-nuclear cyanines and merocyanines), oxonols, hemioxonols, styryls, merostyryls and streptocyanines.
[0020] The binder or protective colloid for the silver halide layer and the layers of the photographic element is preferably gelatin, but other hydrophilic colloids or synthetic water insoluble polymers in the form of latexes can be used to partially or completely replace gelatin.
[0021] In addition, the photographic elements of the present invention may also contain any photographic additives known in the art, such as for example, stabilizer, antifoggants, hardeners, plasticizers, other development accelerators, gelatin extenders, matting agents and the like.
[0022] To achieve the benefits of this invention, a hydrazine compound has to be present during development of the exposed element. It is essential that the element contain one or both of a 3-pyrazolidinone or 2-pyrazoline developer and surfactant prior to contact with the whole developer solution. By "contact with the whole developer solution" is meant that the exposed element is placed into contact with all of the required developer ingredients. Many different combinations of developer ingredients are available and the usual solution has a minimum of two developers (exclusive, of course of the developer of this invention), antioxidant (e.g., sulfite, although ascorbic acid is also described), and a contrast promoting agent (e.g., alkanol-amine, alcohol, or carbinol).
[0023] The hydrazine compound can be incorporated in the photographic element or in the developing solution or both in the developing solution and in the photographic element. It is preferred to be in at least the element itself.
[0024] Hydrazine and any water soluble hydrazine derivatives are effective to increase contrast when incorporated in the developing solution in combination with the diarylmethanol compound incorporated in the photographic element. Preferred hydrazine derivatives to be used in the developing solution or emulsions of this invention include compounds of formula:
wherein R₅ is an organic radical and R₆, R₇, and R₈ each are hydrogen or an organic radical. Organic radicals represented by R₅, R₆, R₇, and R₈ include hydrocarbon groups, such as an alkyl group, an aryl group, an arylalkyl group and an alicyclic group and such groups can be substituted with substituents such as alkoxy groups, carboxy groups, sulfonamido groups and halogen atoms.
[0025] Other examples of hydrazine derivatives, which can be incorporated in the developing solutions, are hydrazides (including aryl hydrazides and formyl hydrazides), acyl hydrazines, semicarbazides, carbohydrazides and aminobiuret compounds.
[0026] Specific examples of hydrazine derivatives, which can be incorported in the developing solutions of the present invention, are disclosed in U.S. Patent Specification 2,419,575.
[0027] In a preferred form of this invention, the hydrazine compound is incorporated in the photographic element, for example, in a silver halide emulsion layer or in a hydrophilic colloidal layer, preferably a hydrophilic colloidal layer adjacent to the emulsion layer in which the effects of the hydrazine compound are desired. It can, of course, be present in the photographic element distributed between the emulsion and the hydrophilic colloidal layers, such as a subbing layer, interlayers and protective layers.
[0028] Hydrazine compounds suitable to be incorporated into the photographic element according to the present invention are disclosed in G.B. Patent Specification 598,108 and in U.S. Patent Specification 2,419,974; they include the water soluble alkyl, aryl and heterocyclic hydrazine compounds, as well as the hydrazide, semicarbazide and aminobiuret compounds.
[0029] Particularly preferred hydrazine compound, for use according to this invention incorporated in the photographic element, are the formylhydrazine compounds corresponding to the formula (IV):
R₄-NHNH-
-R²⁰ (IV)
wherein R₄ represents a substituted or unsubstituted aromatic group and R²° is selected from hydrogen, aliphatic groups (e.g., alkyl or substituted alkyl of 1 to 20 carbon atoms), and aromatic groups (including substituted aromatic groups such as phenyl substituted with alkyl, alkoxy, carboxy, hydroxy, carboxy alkyl, etc. of up to 30 carbon atoms). Examples of aromatic groups represented by R₄ include a phenyl group and a naphthyl group. Such aromatic groups may be substituted with one or more substituents which are not electron attracting, such as straight or branched-chain alkyl groups (e.g., methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, n-octyl, n-hexyl, tert-octyl, n-decyl, n-dodecyl, etc.), arylalkyl groups (e.g., benzyl, phenethyl, etc.), alkoxy groups (e.g., methoxy, ethoxy, 2-methyl-propyloxy, etc.), amino groups which are mono- or disubstituted with alkyl groups, acylaminoaliphatic groups (e.g., acetylamino, benzoylamino, etc.), etc., as disclosed in U.S. Patent 4,168,977 and a CA Patent 1,146,001. Such aromatic groups may also be substituted with a ureido group of formula:
R₉ and R₁₀ (which may be same or different) each represents hydrogen, an aliphatic group (such as a straight or branched-chain alkyl groups, a cycloalkyl group, a substituted cycloalkyl group, an alkenyl group and an alkynyl group), an aromatic group (such as a phenyl group and a naphthyl group) or a heterocyclic group; R₁₁ represents hydrogen or an aliphatic group (such as those listed above) as described in U.S. Patent 4,323,643.
[0030] Other hydrazine compounds, for use according to this invention, incorporated in the photographic element, are those represented by the formula:
R₁₂-NHNH-
-R₁₃
wherein R₁₂ represents the same aromatic group of the formula above and R₁₃ represents an alkyl group have 1 to 3 carbon atoms, which may be a straight or branched-chain alkyl (e.g., methyl, ethyl, n-propyl and isopropyl) or a phenyl group. The phenyl group may be substituted with one or more substituents which preferably are electron attracting groups, such as halogen atoms (chlorine, bromine, etc.), a cyano group, a trifluoromethyl group, a carboxy group or a sulfo group, etc. Specific examples of hydrazine compound represented by the formula above are disclosed in U.S. Patent 4,224,401.
[0031] Still other examples of hydrazine compounds, for use according to this invention incorporated in the photographic element, are those corresponding to the formula:
wherein R₁₄ represents hydrogen, an aliphatic group which may be substituted; Y represents a divalent linking group; m represents 0 or 1; X represents a divalent aromatic groups (such as for example a phenylene group, a naphthylene group and the analogous substituted groups thereof); R₁₅ represents a hydrogen atom, an aliphatic groups which may be substituted and Z represents a non metallic atom group necessary to form a 5- or a 6-membered heterocylcic ring. Specific examples of hydrazine compounds represented by the formula above are disclosed in U.S. Patent 4,272,614
[0032] In one particular preferred form, the hydrazine compound to be incorporated in the photographic element is substituted with ballasting groups, such as the ballasting groups of incorporated color couplers and other non-diffusing photographic emulsion addenda. Said ballasting groups contain at least 8 carbon atoms and can be selected from the relatively non-reactive aliphatic and aromatic groups, such as alkyl, alkoxy, alkylphenyl, phenoxy, alkylphenoxy groups and the like. In cases where the highest rate of development is preferred, and where the prctice of the present invention is most preferred, the hydrazides should have pendant groups of fewer than 8 carbon atoms, preferably 4 or fewer carbon atoms, and most preferably with none or at most one carbon atom.
[0033] Such hydrazine compounds can be incorporated in the photographic element using various methods well-known in the photographic art, the most common being the method of dissolving the hydrazine derivatives in a high boiling crystalloidal solvent and dispersing the mixture in the emulsion, as described for example in U.S. Patent 2,322,027.
[0034] Hydrazine compounds incorporated in the developing solution in the practice of this invention are effective at low concentrations. For example, hydrazine compounds give useful results in the developing solution in a quantity of about 0.001 moles per liter to about 0.1 moles per liter, more preferably in a quantity from about 0.002 to about 0.01 moles per liter. Hydrazine compounds incorporated in the photographic element are typically employed in a concentration ranging from about 5 x 10⁻⁴ to about 5 x 10⁻² moles per mole of silver and preferable in a quantity from about 8 x 10⁻⁴ to about 5 x 10⁻³ moles per mole of silver.
[0035] Contrast promoting agents such as alkanolamines and diarylcarbinol compounds, preferably the diarylcarbinols such as diarylmethanol compounds described herein, are incorporated into the developer bath or preferably the photographic element prior to contact with the whole developer solution and preferably prior to the exposure of the photographic element itself, such as for example, when the diarylcarbinol compound is introduced into the element prior to or contemporaneously with the coating of the emulsion layer. For example, they can be incorporated in the silver halide emulsion layer of the element or in a hydrophilic colloidal layer of the element, particularly a hydrophilic colloidal layer adjacent to the emulsion layer in which the effects of the diarylcarbinol compounds are desired. They can, for instance, be present in the photographic element distributed between the emulsion and the hydrophilic colloidal layers, such as for instance a subbing layer, interlayers and protective layers.
[0036] The aromatic groups represented by R₁, R₂, and R₃ of formulas (I), (II), and (III) above include a naphthyl group and, preferably, a phenyl group. The alkyl groups represented by R₃ of formulas (I) and (II) above include branched or straight-chain alkyl groups, preferably low alkyl groups (having from 1 to 5 carbon atoms). Such groups may contain substitutents, such substituents being chosen in nature and size as not to negatively affect their behavior according to the present invention. For what concern their nature, such substituents include for example an alkyl group, an alkoxy group, a cyano group, a dialkylamino group, an alkoxycarbonyl group, a carboxy group, a nitro group, an alkylthio group, a hydroxy group, a sulfoxyl group, a carbamoyl group, a sulfamoyl group, a halogen atom, etc. For what concerns their size, such substituents are preferred to have from 1 to 10 carbon atoms, more preferably from 1 to 5 carbon atoms.
[0037] Parameters to take into proper account are solubility and boiling points of the diarylcarbinol compounds of the present invention. Said compounds are to be substantially soluble in water or soluble in water miscible solvents (by "substantially soluble" in water is meant that they are to be soluble in water in a quantity of at least 1% by weight and by "soluble" in water-miscible solvents it is meant that they are to be soluble in water miscible solvents in a quantity of at least 5% by weight) in order to introduce them into the aqueous coating compositions used to form the layers of the photographic elements according to the present invention. Said diarylcarbinol compounds are required to have a sufficiently high boiling point not to evaporate during drying of the layer forming coating composition. Said boiling points are preferably higher than 150°C, more preferably higher than 200°C.
[0038] Specific examples of diarylcarbinol compounds according to this aspect of the invention include the following:
1) diphenylmethanol (a.k.a. benzhydrol)
2) 4,4′-dimethoxydiphenylmethanol
3) 4,4′-dimethyldiphenylmethanol
4) 2,2′-dibromodiphenylmethanol
5) 4,4′-dibromodiphenylmethanol
6) 2,2′-dinitrodiphenylmethanol
7) 4,4′-dinitrodiphenylmethanol
8) 2,3′-dimethoxydiphenylmethanol
9) 2,4′-dihydroxydiphenylmethanol
10) 4-methyldiphenylmethanol
11) 4-ethyldiphenylmethanol
12) 2,2′,4,4′-tetramethyldiphenylmethanol
The diarylcarbinol compounds are preferably used in the present invention, when incorporated into the photographic element in amounts from about 10⁻⁴ to about 10⁻¹ mole per mole of silver, more preferably in an amount from about 10⁻³ to about 5 x 10⁻² mole per mole of silver.[0039] According to the process of the present invention, the image-wise exposed silver halide photographic element can be processed with a stable aqueous alkaline developing solution to produce a high contrast negative image. This contrast is the slope for the straight line portion of the characteristic sensitometric curve (referred to as "average contrast") and is measured between two points located at densities of 0.10 and 2.50 above fog. Averages contrast higher than 10 can be obtained according to this invention by developing an image-wise exposed element in the presence of a hydrazine compound. As a consequence of the lower pH in the developer bath, the developer and/or surfactant in the element, and the preferable presence of the diarylcarbinol compound in the element, the process can be carried out to obtain the desired high contrast characteristics by using a conventional rapid access type developing solution which is stable during the time to the aerial oxidation (the higher the pH, the lower being the stability of the developing solution, as known to those skilled in the art) independently from the presence of contrast promoting agents in the developing solution of the type described in the above mentioned U.S. Patent 4,269,929 and European Patent Application 155,690. This can also be done with reduced swirl patterns being observed on the developed image.
[0040] The dihydroxybenzene developing agents employed in the aqueous alkaline developing solution for use in the practice of this invention are well-known and widely used in photographic processings. The preferred developing agent of this class is hydroquinone. Other useful dihydroxybenzene developing agents include chlorohydroquinone, bromohydroquinone, isopropylhydroquinone, tolylhydroquinone, methylhydroquinone, 2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone, 2,3-dibromohydroquinone, 1,4-dihydroxy-2-acetophenone-2,5-dimethylhydroquinone, 2,5-diethylhydroquinone, 2,5-di-p-phenethylhydroquinone, 2,5-dibenzoylhydroquinone, 2,5-diacetaminohydroquinone and the like.
[0041] The 3-pyrazolidone developing agents employed in the emulsion (and which may or may not be present in the aqueous alkaline developing solution) in the practice of this invention are also well known and widely used in photographic processings. The most commonly used developing agents of this class are 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone and 1-phenyl-4,4-dihydroxy-methyl-3-pyrazolidone. Other useful 3-pyrazolidone developing agents include: 1-phenyl-5-methyl-3-pyrazolidone, 1-p-aminophenyl-4-methyl-4-propyl-3-pyrazolidone, 1-p-chlorophenyl-4-methyl-4-ethyl-3-pyrazolidone, 1-p-acet-amidophenyl-4,4-diethyl-3-pyrazolidone, 1-p-Beta-hydroxy-ethylphenyl-4,4-dimethyl-3-pyrazolidone, 1-p-hydroxy-phenyl-4,4-dimethyl-3-pyrazoidone, 1-p-methoxyphenyl-4,4-diethyl-3-pyrazolidone, 1-p-tolyl-4,4-dimethyl-3-pyrazolidone, and the like.
[0042] The prefered aqueous alkaline photographic developing composition for use in the practice of this invention contains a sulfite preservative at a level sufficient to protect the developing agents against aerial oxidiation and thereby assure good stability characteristics. Useful sulfite preservatives include sulfites, bisulfites, metabisulfites and carbonyl bisulfite adducts. Typical examples of sulfite preservatives include sodium sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite, potassium metabisulfite, sodium formaldehyde bisulfite salt and the like. Also ascorbic acid is a known preservative agent against aerial oxidation of the developer for use in the bath according to this invention.
[0043] The aqueous alkaline developing solutions for use in the practice of this invention can vary widely with respect to the concentration of the various ingredients included therein. Typically, the dihydroxybenzene developing agent is used in an amount of from 0.040 to about 0.70 moles per liter, more preferably in an amount of from 0.08 to about 0.40 moles per liter; the 3-pyrazolidone developing agent is used in an amount of from about 0.001 to about 0.05 moles per liter, more preferably in an amount of from about 0.005 to about 0.01 moles per liter; the sulfite preservative is used in an amount from about 0.03 to about 1.0 moles per liter, more preferably in an amount from about 0.10 to about 0.70 moles per liter.
[0044] In contrast with "lith" developers which require a low level of sulfite ions, the developing solutions of this invention can utilize higher levels of sulfite ions, and thereby achieve the advantages of increased stability, since a higher level of sulfite ions provides increased protection against aerial oxidation.
[0045] In carrying out the method of this invention, it is preferred to use an organic antifogging agent to minimize fog formation in the processed element. The organic antifogging agent can be incoporated in the photographic element or can be added to the developing solution or can be both incorporated in the photographic element and added to the developing solution. According to the present invention, it has been found that more preferred organic antifogging agents for specific use in the developing solutions are benzotriazole and/or a benzimidazole antifogging agent, which proved to have beneficial effects on increasing contrast. Useful compounds are both substituted and unsubstituted benzotriazole and benzimidazole compounds, with the proviso that electron withdrawing substituents at least as strong as nitro groups are excluded. As a matter of fact, nitro substituted benzotriazole and benzimidazole compounds, although good to prevent fog, do not provide beneficial effects with reference to contrast increase. Benzimidazoles and benzotriazoles, as a class, are believed to be useful in the practice of this invention. Anyhow, as indicated, difficulties in obtaining significantly improved performance with benzotriazoles and benzimidazoles having strong electron withdrawing groups have been encountered. Benzotriazoles and benzimidazoles are therefore preferred not to have any substitutents on the aromatic rings which are electron attracting groups as strong as or stronger than a nitro group. Other substituents known in the art such as lower alkyl groups (having 1 to 5 carbon atoms) and halogen substituents (chlorine) proved to be substituents good to the purposes of the invention. Said benzotriazole and benzimidazole antifogging and contrast promoting agents are normally used in amounts effective to prevent fog, although their quantity can be optimized to get the best results from the contrast point of view. Useful quantities, when they are included in the emulsion, may vary from 1 to 100 milligrams per 100 grams of emulsion and, when included in the developing bath, as preferred, may vary from 0.01 to 5 grams per liter.
[0046] In addition to the essential components specified hereinabove, the developing solutions can optionally contain any of a wide variety of addenda, as known, useful in photographic developing solutions. For example, they can contain solvents, buffers, sequestering agents, development accelerators, agents to reduce selling of the emulsion layers, and the like.
SURFACTANT DESCRIPTION
[0047] The surfactants useful in the practice of the present invention have been found to be limited to the classes of ethoxylated or propoxylated alcohols and fluorinated surfactants, such as those disclosed in U.S. Patent 2,759,019 and 2,915,554. The ethoxylated or propoxylated alcohols are preferred. An example of a most preferred surfactant is Antarox™ BL-240 which is a mixed octyl/decyl alcohol ethoxylated (and possibly also propoxylated) with a composite molecular formula of C₃₁H₆₄O₁₀ and a molecular weight of about 596 (trade literature indicating a MW of 582). The average formula appears to be:
The compounds must in fact act as surfactants and this will generally require at least one surface active functionality (e.g., hydroxyl group) with a ratio of less than 20 total ethoxy and propoxy groups (preferably less than 16, more preferably less than 10) in the molecule per surfactant functionality. It is preferred that the surfactants have a molecular weight less than 1,000 and more preferably less than 800. Many other commercially available ethoxylated alcohol surfactants such as Emulphor™, Tergitol™, Volpo™, etc., can be used in the practice of the present invention. Other useful surfactants are shown as coating aids in U.S. 3,769,022 and 2,831,766 and surfactants in U.S. Patent 4,511,641. In appreciating the present invention, it is to be noted that the swirl patterns are not coating defects but are development defects. Analysis of the layers prior to development or upon less active development do not show these swirl defects, indicating that it is not a result of coating defects.
[0048] It has been found that the developing agents of the present invention should be added into the silver halide emulsion layer in an amount of from 0.001 to 0.050 g/m² to be effective. Preferably the developer is used in an amount of 0.003 to 0.40 g/m² and most preferably as 0.005 to 0.030 g/m². The surfactants are to be used in the topcoat layer in a range of from 0.010 to 0.5 g/m², preferably from 0.020 to 0.4 g/m², and more preferably from 0.050 to 0.30 g/m².
[0049] A combination of both the auxiliary developing agent in the silver halide emulison layer and the surfactant in the topcoat improves the performance of the film beyond the additive effects of the individual materials. In particular, the induction time for initial observable development can be reduced by the combination of these additives.
[0050] Although there is a general reference in the hydrazide high contrast art to the use of developing agents in the emulsion (e.g., U.S. 4,560,638 and 4,618,574), there is not disclosure of phenidone type developers specifically in the emulsion layers. Although U.S. Patents 4,619,886; 4,650,746 and 4,168,977 as well as Japanese Patent Publication J 60129746 teach the general utility of 3-pyrazolidone type (phenidone type) developing agents in the developer bath, the publications do not suggest the use of those developers in the emulsion. The swirl pattern reduction effect is observed only when the phenidone developer is present in the emulsion (directly or by migration from other layers), and no benefit is observed when the developer is only in the developing bath.
EXAMPLE #1
[0052]
| Coating Layer | A |
| Emulsion | 3.1 gmAg/m² |
| potassium bromide | 0.034 gm/m² |
| Spectral sensitizing dye | 0.007 |
| Brij 58 (ethoxylated alcohol with mol. wt greater than 1000) | 0.043 |
| Hostapur SAS-93 | 0.049 |
| Hydrazide Dispersion Solution (containing 2-(4-n-butylphenyl)-o-hydroxymethylbenzoy) hydrazide | 0.798 |
| Benzhydrol | 0.041 |
| Ascorbic acid | 0.003 |
| Triazine | 0.102 |
| Coating Layer | B |
| Inert gelatin | 0.704 gm/m² |
| Hostapur SAS-93 (coating aid) | 0.061 |
| silica (matting agent) | 0.029 |
| Triazine (hardener) (HA-22= 4,6-dichloro-1,3,5-trizine 2(1H)one, monosodiuum salt | 0.095 |
[0053] Also added to the above layer A coating formulation were the following developer compounds. Only the 3-pyrazolidinones (Examples 2-5) and 2-pyrazolines (Examples 8 and 9) provided benefits in the present invention, showing the uniqueness of those classes.
| Swirl 1 | Swirl 2 | ||
| 1. No additions | 0.000 gm/m² | 5 | 3 |
| 2. Phenidone A | 0.004 | 4 | 1.5 |
| 3. Phenidone A | 0.010 | 3.5 | 1.5 |
| 4. Dimezone | 0.004 | 4 | 2.5 |
| 5. Dimezone | 0.010 | 4 | 2 |
| 6. Metol | 0.004 | 4.5 | 3 |
| 7. Metol | 0.010 | 4 | 3.5 |
| 8. Pyrazolin (C₁₀H₁₀N₂O) | 0.004 | 4.5 | 2.5 |
| 9. " | 0.010 | 4.5 | 2.2 |
| 10. Tetrachlorohydroquinone | 0.004 | 5 | 3 |
| 11. " | 0.010 | 5 | 3.5 |
| 12. Spirobiindone | 0.004 | 4.5 | 4 |
| 13. " | 0.010 | 4 | 3 |
| 14. Propyl Gallate | 0.004 | 4 | 4 |
| 15. " | 0.010 | 4.5 | 4 |
Phenidone A is 1-phenyl-3-pyrazolidinone
Pyrazolin is 3-methyl-1-phenyl-2-pyrazolin-5-one
Dimezone S is 4-hydroxylmethyl-1-4-methyl-1-phenyl-3-pyrazolidone
Dimezone is
Amidol is 2,4-diaminophenol dihydrochlor
Example of Exposure Method:
[0054] The materials are subjected to suitable radiation from a point light source traveling through a Kodak Wratten series 00 filter to a film sample under vacuum drawdown with a overlayed Kodak 133 line magenta contact screen producing a halftone dot density after processing of about 70%.
[0055] Typical fluorinated surfactants have a highly fluorinated (at least two-thirds of all substituents on carbons in a portion of the group) or perfluorinated group bonded to a surfactant group (e.g., polyoxoalkyl groups such as -O(CH₂)n- wherein n is 2 or 3 having terminating hydroxyl or methoxy groups or the like). Typical examples are
RfSO₂
CH₂
m(O[CH₂]p
OR₁
wherein Rf is a highly fluorinated or perfluorinated group, R is H or alkyl of 1 to 4 carbon atoms, m and p are 2 or 3, and R¹ is hydrogen or methyl.
[0056] Other fluorinated surfactants are represented by the formula
wherein Rf is as defined above, q is 2 to 6, R¹ and R² and R³ are independently alkyl groups of 1 to 8 carbon atoms (preferably 1 to 3 carbon atoms) and A is an anion.
Example of Processing Solutions and Conditions:
[0057]
| DEVELOPER EXAMPLE (Developer at 100°F) | |
| Water | 1800.00 gm |
| Potassium hydroxide | 195.00 gm |
| Potassium metabisulfite | 124.00 gm |
| DTPA (40%) | 10.00 gm |
| Pyruvic acid | 7.50 gm |
| Hydroquinone | 60.00 gm |
| Metol | 5.00 gm |
| 5-Methylbenzotriazole | 0.20 gm |
| Potassium bromide | 9.25 gm |
| Potassium chloride | 2.70 gm |
| Phosphoric acid | 90.00 gm |
| Final volume | 2.00 liters |
| 11.00 pH | |
| PART-A WORKING SOLUTION (Fix at 100°F) | |
| Water | 0.12530 1 |
| Ammonium thiosulfate | 0.77990 1 |
| Sodium sulfite | 63.9093 gm |
| Boric acid | 29.2385 gm |
| Sodium acetate | 32.8334 gm |
| Acetic acid (Glacial) | 42.3399 gm |
| Total | 1.0 liter |
[0058] The exposed element is then machine processed after exposure for 30 seconds in the above developer followed by a 30 second immersion in the fix and a water bath before drying. Because of the uniform lower screened tint density, any irregularity or fluctuation density defects caused by the mechanical processing forces are greatly enhanced providing a method for evaluation. The term internally applied to this defect is "swirl" and has been given a ranking system of 0-5. 0 is equal to a near zero observation of any defects up to 5 which is a visible woodgrain type defect or other severe processing pattern. The results of the above coating additives are included in the above table under Swirl 1.
[0059] The Table clearly demonstrates that adding phenidone to the emulsion layer improved the "swirl" defect level by 1-1/2 units when employing the optimum level of 0.01 grams phenidone per meter squared. In addition to this favorable improvement, the materials containing the phenidone also visually demonstrates a more consistent overall density in the sheets of processed film. None of the other auxiliary developers had any noticeable positive effects on these problem areas.
[0060] Comparison of coating #1 in the Table under Swirl 2 demonstrates the reduction of defect level from the addition of an optimum level of Antarox BL-240 to layer B. This reduced the "swirl" defect level 2 units.
[0061] A synergistic effect has been found when phenidone and ethoxylated alcohols (such as BL-240) are used in combination producing a total overall effect on "swirl" improvement of at least 3.5 units.
[0062] The synergism effect is achieved, for example, when coating the following layer C over layer A in Example 1 Coating #2.
| Coating Layer | C |
| Inert gelatin | 0.704 gm/m² |
| Hostapur SAS-93 | 0.061 |
| Silica | 0.029 |
| Antarox BL-240 | 0.141 |
| Triazine | 0.095 |
EXAMPLE #2
[0063] A three variable central composite design coated in accordance with the emulsion finals found in Example 1 with the exception that a broader range of phenidone was added into this layer and the HA-22 hardener was omitted. The remaining two variables/ranges are contained in the topcoat layer now containing 0.1623 gm/m² of HA-22. These coatings also differ from Example 1 layer C because the two layers were coated simultaneously. The material was exposed and processed as in Example 1 before "swirl" ranking. Design level of variables are -
| EMULSION | TOPCOAT | |
| Phenidone | BL-240 | Gelatin |
| +α 0.0482 | 0.330 | 1.0404 gm/m² |
| + 0.0399 | 0.2820 | 0.9479 |
| CP 0.0262 | 0.2115 | 0.8123 |
| - 0.0131 | 0.1410 | 0.6767 |
| -α 0.00318 | 0.0929 | 0.5842 |
-0.696 for phenidone
-0.824 for BL-240
0.0 for gelatin
1. A silver halide photographic element which has not undergone development sensitizing
exposure to actinic radiation, including at least one negative acting surface latent
image-type silver halide emulsion layer and a hydrazine compound, said element being
characterized by the presence of a swirl pattern reducing amount of at least one additive
selected from a) a 3-pyrazolidinone or 2-pyrazoline developing agent in reactive
association with said silver halide and b) in a topcoat layer, a surfactant selected
from the class consisting of alkoxylated alcohols and fluorinated surfactants.
2. A silver halide photographic element which has not undergone development sensitizing
exposure to actinic radiation, including at least one negative acting surface latent
image-type silver halide emulsion layer and a hydrazine compound, said element having
a contrast promoting amount of a diarylcarbinol contrast promoting agent in reactive
association with said silver halide emulsion layer, wherein the diarylcarbinol compound
has the formula (I) or (II):
R₁R₂R₃COH (I)
R₁R₂R₃C(CH₂)nOH (II)
wherein R₁ and R₂ each represent a substituted or unsubstituted aromatic group, R₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group and n represents a positive integer from 0 to 4, and wherein said diarylcarbinol is incorporated in the silver halide emulsion layer in an amount from about 10⁻⁴ to 10⁻¹ mole per mole of silver halide and said element having a swirl pattern reducing amount of an additive selected from the group consisting of a) a 3-pyrazolidinone or 2-pyrazoline developer in the emulsion and b) in a topcoat layer, a surfactant selected from the group consisting of alkoxylated alcohols and fluorinated surfactants.
R₁R₂R₃COH (I)
R₁R₂R₃C(CH₂)nOH (II)
wherein R₁ and R₂ each represent a substituted or unsubstituted aromatic group, R₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group and n represents a positive integer from 0 to 4, and wherein said diarylcarbinol is incorporated in the silver halide emulsion layer in an amount from about 10⁻⁴ to 10⁻¹ mole per mole of silver halide and said element having a swirl pattern reducing amount of an additive selected from the group consisting of a) a 3-pyrazolidinone or 2-pyrazoline developer in the emulsion and b) in a topcoat layer, a surfactant selected from the group consisting of alkoxylated alcohols and fluorinated surfactants.
3. The element of claim 1 wherein alkoxylated alcohols are present in said topcoat
layer and said alcohols are selected from the group consisting of ethoxylated and
propoxylated alcohols.
4. The element of claim 3 wherein there is a ratio of less than 20 ethoxy and propoxy
groups to each surfactant group.
5. The element of claim 4 wherein said surfactant group contains an hydroxyl group.
6. The element of claims 1-5 additionally containing said developer in said emulsion
layer, and said developer comprises a 3-pyrazolidinone developer.
7. The element of claims 1-5 wherein said hydrazine has the formula:
R-NHNH-
R¹
wherein R is an aromatic group and R1 is selected from hydrogen, alkyl, and aromatic groups.
R-NHNH-
R¹
wherein R is an aromatic group and R1 is selected from hydrogen, alkyl, and aromatic groups.
8. The element of claim 6 wherein said hydrazine has the formula:
R-NHNH-
R¹
wherein R is an aromatic group and R1 is selected from hydrogen, alkyl, and aromatic groups.
R-NHNH-
R¹
wherein R is an aromatic group and R1 is selected from hydrogen, alkyl, and aromatic groups.
9. A silver halide photographic element which has not undergone develpment sensitizing
exposure to actinic radiation, including at least one negative acting surface latent
image-type silver halide emulsion layer and a contrasting promoting hydrazine compound,
said element being characterized by the presence of a swirl pattern reducing amount
of at least one additive selected from a) an auxiliary developing agent in reactive
association with said silver and b) in a topcoat layer, a surfactant selected from
the class consisting of alkoxylated alcohols and fluorinated surfactants wherein said
surfactant is present in said topcoat layer in an amount of from 0.010 to 0.5g/m²
and said surfactant comprises an ethoxylted or propoxylated alcohol with a ratio of
the ethoxy and propoxy groups to hydroxyl surfactant groups of less than 16 and wherein
said emulsion layer contains a 3-pyrazolidinone auxiliary developer in an amount of
from 0.001 to 0.5 g/m².
10. A silver halide photographic element which has not undergone development sensitizing
exposure to actinic radiation, including at least one negative acting surface latent
image-type silver halide emulsion layer and a contrasting promoting hydrazine compound,
said element having a contrast promoting amount of a diarylcarbinol contrast promoting
agent in reactive association with said silver halide emulsion layer, wherein the
diarylcarbinol compound has the formula (I) or (II):
R₁R₂R₃COH (I)
R₁R₂R₃C(CH₂)nOH (II)
wherein R₁ and R₂ each represent a substituted or unsubstituted aromatic group, R₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group and n represents a positive integer from 0 to 4, and wherein said diarylcarbinol is incorporated in the silver halide emulsion layer in an amount from about 10⁻⁴ to 10⁻¹ mole per mole of silver halide and said element having a swirl pattern reducing amount of an additive selected from the group consisting of a) a 3-pyrazolidinone developer in the emulsion and b) in a topcoat layer, a surfactant selected from the group consisting of alkoxylated alcohols and fluorinated surfactants wherein said surfactant is present in said topcoat layer in an amount of from 0.010 to 0.5g/m² and said surfactant comprises an ethoxylted or propoxylated alcohol with a ratio of the ethoxy and propoxy groups to hydroxyl surfactant groups of less than 16 and wherein said emulsion layer contains a 3-pyrazolidinone auxiliary developer in an amount of from 0.001 to 0.5 g/m².
R₁R₂R₃COH (I)
R₁R₂R₃C(CH₂)nOH (II)
wherein R₁ and R₂ each represent a substituted or unsubstituted aromatic group, R₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group and n represents a positive integer from 0 to 4, and wherein said diarylcarbinol is incorporated in the silver halide emulsion layer in an amount from about 10⁻⁴ to 10⁻¹ mole per mole of silver halide and said element having a swirl pattern reducing amount of an additive selected from the group consisting of a) a 3-pyrazolidinone developer in the emulsion and b) in a topcoat layer, a surfactant selected from the group consisting of alkoxylated alcohols and fluorinated surfactants wherein said surfactant is present in said topcoat layer in an amount of from 0.010 to 0.5g/m² and said surfactant comprises an ethoxylted or propoxylated alcohol with a ratio of the ethoxy and propoxy groups to hydroxyl surfactant groups of less than 16 and wherein said emulsion layer contains a 3-pyrazolidinone auxiliary developer in an amount of from 0.001 to 0.5 g/m².