JPH0571930B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a silver halide photographic paper with improved whiteness of the white background of thin photographic paper, and more specifically, an oil-soluble fluorescent agent is added to the silver halide emulsion layer of the support. and the use of oil-soluble dyes on the opposite side to improve whiteness. PRIOR ART It is a well-known technique to apply optical brighteners to enhance the whiteness of the processed substrate of silver halide photographic paper. These fluorescent brighteners absorb ultraviolet light and usually emit slightly bluish fluorescence, making objects appear whiter. Such optical brightening methods have long included adding optical brighteners to the paper support or its polyethylene laminate layer, as well as adding water-soluble optical brighteners to the silver halide emulsion layer or other photographic coating layers. A method of adding a whitening agent or an oil-soluble fluorescent brightener, and a method of adding a fluorescent brightener to a developing solution in advance are known. However, in the case of silver halide photographic paper made of a polyethylene laminated paper support, which is particularly suitable for rapid processing, if an attempt is made to incorporate an optical brightener into the laminate layer, the laminate layer will be damaged due to the poor thermal stability of the optical brightener. There are drawbacks such as the fact that optical brighteners tend to decompose during the heating extrusion process during layer formation, and when applying optical brighteners during the development process, it is necessary to maintain a constant concentration throughout the process. If you don't take measures to maintain it, there are inconveniences such as not being able to maintain the uniformity of the finish.
Most preferably, a fluorescent brightener is included in the photographic layer in advance. In particular, in the method of adding an optical brightener to the photographic layer, an oil-soluble optical brightener is used rather than a water-soluble optical brightener to prevent the optical brightener from being washed away during the development process. For this purpose, an oil-soluble optical brightener is dissolved in an organic solvent and added to the gelatin layer as an emulsified dispersion, as described in British Patent No. 1072915. method is known. On the other hand, although visual whiteness varies depending on individual preference, it is also known that, in general, a bluish white looks whiter than a neutral white. Furthermore, in silver halide photographic elements, undesirable light absorption on white backgrounds is caused by the yellowing of natural polymers such as gelatin used as binders, synthetic polymers such as polyvinylpyrrolidone and polyvinyl alcohol, and the yellowing of silver halide emulsions. residual color due to silver and pigments due to fog, residual color due to sensitizing dyes and anti-irradiation dyes, dyeing of colored substances in the processing machine, and problems such as couplers, antioxidants, and ultraviolet absorbers, which are especially problematic with color photographic paper. Examples include yellowing and the formation of colored pigments by couplers and developing agents that occur without development of silver halide.In order to visually cancel out these so-called residual colors, it is a means to adjust the hue of the white background by adding a blue tint. As seen in JP-A No. 53-19021, there is a method for controlling the hue of the support surface by incorporating an inorganic coloring pigment into the polyolefin of polyolefin coated paper, and as shown in JP-A-55-93150. A known method is to use an oil-soluble dye in the photographic layer to adjust the hue in the photographic layer. Hue adjustment on the surface of the support involves the complexity of preparing the support according to the optical properties of the various photographic layers, and extrusion coating of polyolefin is usually performed at high temperatures of 300°C or higher, and the colorant is It must satisfy requirements such as having heat resistance of 300℃ or more, no bleed-out, no sublimation, and good dispersibility in polyolefin, which narrows the range of colorant selection. In this respect, it is advantageous to incorporate the colorant in the photographic layer. In particular, in recent years, rapid processing using automatic processors has become widespread, and the above-mentioned residual color of sensitizing dyes and the like has become a more serious problem. JP-A-60-154251 describes that when a sensitizer and a dye are used together in the same layer, the brightness is reduced. In other words, the whiteness is improved by having an oil-soluble optical brightener and an oil-soluble dye in different photographic layers, but in this case as well, the whiteness of the dye can be improved by adjusting the whiteness. Increasing the amount added has the disadvantage of decreasing brightness. (Object of the Invention) Therefore, an object of the present invention is to provide a silver halide photographic paper having a white background with high brightness and good whiteness. (Structure of the Invention) An object of the present invention is to provide a photographic paper having a silver halide emulsion layer on a reflective support, in which the reflective support has a transmission density of 0.8 or less, and a silver halide emulsion layer on the support. This is achieved by containing an oil-soluble optical brightener in the silver emulsion layer and further containing an oil-soluble dye on the side opposite to the support. As a result of our studies, we found that using an oil-soluble fluorescent agent and an oil-soluble dye in the same emulsion layer, as described in JP-A-60-154251, gives good whiteness, but if the dye is increased by adjusting the whiteness, the lightness decreases. accompanied by a decrease in However, by using dyes on the back side of the support,
It was found that the decrease in brightness was small and the whiteness was improved. When using an oil-soluble dye on the back side of the support opposite to the photographic emulsion layer, the transparency of the support has a large effect; as the transmission density of the support increases, the amount of dye used increases; If the transmission density is 0.8 or less, it will not be affected much. Preferably, the transmission density of the support is in the range of 0.7 to 0.3. The fluorescent agent used in the photographic emulsion layer is an oil-soluble fluorescent agent dissolved in a high-boiling organic solvent and used as an emulsified dispersion. Other methods include dissolving it in a monomer in advance and then polymerizing it to form a latex dispersion, or impregnating it into a hydrophobic polymer using an auxiliary solvent and using it as a latex dispersion. It is also possible to use a water-soluble fluorescent agent as described in Japanese Patent Publication No. 48-30495, but the brightness does not improve as expected due to the fluorescent whitening agent flowing out during the development process. . As oil-soluble optical brighteners used in the present invention, for example, substituted stilbenes and substituted coumarins described in British Patent No. 786234, substituted thiophenes described in U.S. Patent No. 3135762, etc. are useful.
Fluorescent brighteners such as those disclosed in Japanese Patent Publication No. 45-37376 and Japanese Patent Application Laid-Open No. 50-126732 can be used particularly advantageously. Typically useful optical brighteners include those having one of the following structural formulas.

[ka]

[ka]

[ka]

[Formula] Here, Y ₁ and Y ₂ are alkyl groups, Z ₁ and
Z ₂ is hydrogen or an alkyl group, n is 1 or 2,
R ₁ , R ₂ , R ₄ and R ₅ are aryl, alkyl, alkoxy, aryloxy, hydroxyl, amino, cyano, carboxyl, amide, ester,
It is an alkylcarbonyl, alkylsulfo or dialkylsulfonyl group or a hydrogen atom. R ₆
and R ₇ is a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, or a cyano group. R ₁₆ is a phenyl group, a halogen atom, or an alkyl-substituted phenyl group. R ₁₅ is an amino group or an organic primary or secondary amine. Next, specific examples of water-insoluble optical brighteners used in the present invention will be given.

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[Table] The method for preparing emulsions of these water-insoluble optical brighteners is to dissolve the optical brightener in a high-boiling organic solvent as exemplified in British Patent No. 1072915, and then dissolve this in a hydrophilic colloid such as gelatin. There is a method of emulsifying and dispersing it with a surfactant. Examples of high boiling point organic solvents include US Pat.
No. 3779765, West German Patent No. 1152610, British Patent
No. 1272561, JP-A-53-1520, JP-A-55-25057
Phthalate esters and phosphate esters such as those described in Japanese Patent Publication No. 45-37376 are generally usable, but are not limited to these, for example, as disclosed in U.S. Pat. No. 3,416,923. Amide compounds, benzoic acid esters, substituted paraffins, and the like can also be advantageously used. If the amount of the fluorescent brightener used is too small, the whiteness improvement effect will not be sufficient, and if it is too large, blooming will occur in areas of high image density, resulting in a decrease in the apparent image density. The luminous efficiency of fluorescence depends on the type of optical brightener, the type and concentration of oil used for emulsification,
Furthermore, it cannot be expressed uniformly because it varies depending on the coexistence of various quenching substances, coexistence of other ultraviolet absorbing substances, etc., but the amount of optical brightener used in the present invention is 3.
Most preferably, it is used in the range of mg to 200 mg/ ^m2 . Further, the ratio of emulsifying oil to the optical brightener is selected and used at an optimum value from the viewpoint of solubility and concentration quenching of the optical brightener. As other means, it may be used as a latex dispersion by first dissolving it in a monomer and then polymerizing it to form a latex dispersion, or by impregnating it into a hydrophobic polymer using an auxiliary solvent. When the fluorescent agent is used as a latex dispersion, a method similar to that for the latex dispersion described in JP-A-50-126732 can be used.
As the dye to be used on the back side of the support, oil-soluble dyes are effective in consideration of migration and outflow due to processing liquids, etc., and are generally dissolved in a high boiling point organic solvent and used as an emulsified dispersion. In addition, it can be used as a latex dispersion by first dissolving it in a monomer and then polymerizing it, or by impregnating it into a hydrophobic polymer using an auxiliary solvent. Any dye can be used in the present invention, and specifically, anthraquinone-based, azo-based, phthalocyanine-based, oxonol-based, and benzylidene-based dyes can be used. Among these, anthraquinone-based, azo-based and phthalocyanine-based dyes are particularly preferably used. Next, a typical example will be shown.

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[Table] The dyes used in the present invention are used for the purpose of adjusting the hue of the white background of photographic paper. It should be selected so that it looks white,
Even if a blue dye or the like is used alone, the absorption characteristics can be adjusted by using two or more of a red dye, a green dye, a blue dye, etc. in combination, if necessary. Although the content of the dye is not particularly limited, it is usually preferably 0.05 mg/m to 5 mg/m. According to the invention, the reflective support used has a transmission density of
Since it is 0.8 or less, a sufficiently thin support can be obtained. In the present invention, any reflective support can be used as long as it has a transmission density of 0.8 or less. For example, any material such as paper, a paper base coated with a resin or the like, synthetic paper, etc. can be used. Although there are no particular limitations on the surface properties of the reflective support used in the present invention, it is preferable that the surface has excellent water resistance. In this case, the water-resistant surface is based on a hydrophobic resin,
For example, it can be formed by coating a paper substrate. In an embodiment in which such a water-resistant surface is formed,
Even when a silver halide photographic light-sensitive material is immersed in a bath used for development processing, it is possible to prevent water from forming on the substrate. For example, if a water-resistant surface is formed by extrusion coating a molten polyolefin onto a paper substrate, a polyolefin-laminated paper with excellent water resistance can be obtained. Examples of the resin used in the hydrophobic resin coating layer coated on the surface include polyolefins such as polyethylene, polypropylene, and polybutene, olefins such as ethylene, propylene, and butene, and monomers such as vinyl acetate, vinylidene chloride, and maleic anhydride. (e.g., ethylene-vinyl acetate copolymer, propylene-vinylidene chloride copolymer, propylene-maleic anhydride copolymer, etc.), or polystyrene, polyvinyl chloride, polyacrylate, saturated polyester, polycarbonate, etc. homopolymers or copolymers, or blends thereof. The thickness of this hydrophobic resin coating layer is
Although there are no particular limitations, it is generally preferred to have a thickness of about 10 to 50 μm. When using polyethylene resin, there is no particular restriction on its molecular weight as long as extrusion coating is possible, but polyethylene having a molecular weight in the range of 20,000 to 200,000 is usually used. Further, the polyethylene resin used for the hydrophobic resin coating layer in this case may be any of low density, medium density, and high density polyethylene resins, and these may be used alone or in combination of two or more types. Further, a fine particle powder having higher heat resistance than the above resin, for example, a white pigment such as BaSO ₄ , ZnO, TiO ₂ or the like may be mixed with the resin, thereby making it possible to obtain an opaque support. In this case, a thin, opaque white support with high transmission density can be obtained by mixing and whitening by forming voids by extrusion or stretching, or by bonding them together. As the binder or protective colloid that can be used in the emulsion layer or hydrophilic colloid layer (e.g., protective layer, intermediate layer) of the light-sensitive material of the present invention, it is advantageous to use gelatin, but other hydrophilic Colloids can also be used. For example, gelatin derivatives, graft polymers of gelatin and other polymers, proteins such as albumin and casein; cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, and cellulose sulfates; sugar derivatives such as sodium alginate and starch derivatives; polyvinyl alcohol , polyvinyl alcohol partial acetal,
Poly-N-vinylpyrrolidone, polyacrylic acid,
A wide variety of synthetic hydrophilic polymeric materials can be used, such as single or copolymers of polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, and the like. In addition to lime-processed gelatin, acid-processed gelatin, Bull.Soc.Sci.Phot.Japan, No. 16,
Enzyme-treated gelatin as described in p. 30 (1966) may be used, and gelatin hydrolysates and enzymatically decomposed products may also be used. Any of silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide, and silver chloride may be used as silver halide in the photographic emulsion layer used in the present invention. The preferred silver halide is silver iodobromide containing up to 15 mole percent silver iodide. Particularly preferred is silver iodobromide containing from 2 mol % to 12 mol % silver iodide. The average grain size of the silver halide grains in the photographic emulsion (the grain size is the grain diameter for spherical or approximately spherical grains, the edge length for cubic grains,
Expressed as an average based on projected area. ) is not particularly limited, but is preferably 3μ or less. The particle size may be narrow or wide. The silver halide grains may have different phases inside and on the surface. Further, the particles may be particles in which a latent image is mainly formed on the surface, or may be particles in which a latent image is mainly formed inside the particle. The photographic emulsion used in the present invention is P. Glafkides
Written by Chimie et Physique Photographique (Paul
Montel Publishing, 1967), GFDuffin
Photographic Emulsion Chemistry (The Focal
Press, 1966), VLZelikman et al.
Making and Coating Photographic Emulsion
(The Focal Press, 1964). That is, any of the acidic method, neutral method, ammonia method, etc. may be used, and the method for reacting the soluble silver salt with the soluble halogen salt may be any one-sided mixing method, simultaneous mixing method, or a combination thereof. good. It is also possible to use a method in which particles are formed in an excess of silver ions (so-called back-mixing method).
One type of simultaneous mixing method is a method of keeping pAg constant in the liquid phase in which silver halide is produced, that is,
A so-called controlled double jet method may also be used. According to this method, a silver halide emulsion having a regular crystal shape and a nearly uniform grain size can be obtained. Two or more types of silver halide emulsions formed separately may be mixed and used. In the process of silver halide grain formation or physical ripening, a cadmium salt, a zinc salt, a lead salt, a thallium salt, an iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, an iron salt or an iron complex salt, etc. may be allowed to coexist. Silver halide emulsions are usually chemically sensitized.
For chemical sensitization, see for example “Die
Grundlagender Photographischen Prozesse
mit Silber−halogeniden” (Akademische
Verlagsgesellschaft, 1968) pages 675-734 can be used. That is, sulfur sensitization using sulfur-containing compounds that can react with active gelatin and silver (e.g., thiosulfates, thioureas, mercapto compounds, rhodanines); reducing substances (e.g., stannous salts, amines, hydrazine derivatives, formamidine sulfinic acid, silane compounds) reduction sensitization method;
Noble metal compounds (e.g., gold complex salts, Pt, Ir,
A noble metal sensitization method using complex salts of periodic table metals such as Pd can be used alone or in combination. The photographic emulsion used in the present invention can contain various compounds for the purpose of preventing fog during the manufacturing process, storage, or photographic processing of the light-sensitive material, or for stabilizing photographic performance. That is, azoles such as benzothiazolium salts, nitroimidazole salts, nitrobenzimidazoles, chlorobenzimidazoles, promobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles. such as benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (especially 1-phenyl-5-mercaptotetrazole); mercaptopyrimidines; mercaptotriazines; Zaindenes, tetraazaindenes (especially 4-hydroxy substituted (1,3,
3a, 7) tetraazaindenes), pentaazaindenes, etc.; many compounds known as antifoggants or stabilizers such as benzenethiosulfonic acid, benzenesulfonic acid, benzenesulfonic acid amide, etc. can be added. For more detailed examples of these and how to use them, see, for example, U.S. Pat. No. 3,954,474;
Those described in No. 3982947 and Japanese Patent Publication No. 52-28660 can be used. The photographic emulsion layer or other hydrophilic colloid layer of the light-sensitive material produced using the present invention contains coating aids, antistatic properties, smoothness improvement, emulsification dispersion, adhesion prevention, and improvement of photographic properties (e.g., development acceleration, high contrast , sensitization)
Various surfactants may be included for various purposes. For example, saponins (steroids), alkylene oxide derivatives (e.g. polyethylene glycol, polyethylene glycol/polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycols Nonionic interfaces such as alkylamines or amides, polyethylene oxide adducts of silicone), glycidol derivatives (e.g. alkenylsuccinic acid polyglycerides, alkylphenol polyglycerides), fatty acid esters of polyhydric alcohols, alkyl esters of sugars, etc. Activator: Alkyl carboxylate, alkyl sulfonate, alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkyl sulfate, alkyl phosphate, N-acyl-N-alkyl taurine, sulfosuccinic acid Contains acidic groups such as carboxy groups, sulfo groups, phospho groups, sulfate ester groups, phosphate ester groups, etc., such as esters, sulfoalkyl polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl phosphate esters, etc. Anionic surfactants; amphoteric surfactants such as amino acids, aminoalkyl sulfonic acids, aminoalkyl sulfates or phosphates, alkyl betaines, amine oxides; alkylamine salts, aliphatic or aromatic quaternary ammonium salts Cationic surfactants such as heterocyclic quaternary ammonium salts such as , pyridinium, imidazolium, and phosphonium or sulfonium salts containing aliphatic or heterocycles can be used. The photographic emulsion layer of the photographic light-sensitive material of the present invention contains, for example, polyalkylene oxide or its derivatives such as ethers, esters, and amines, thioether compounds, thiomorpholins, and quaternary ammonium salts for the purpose of increasing sensitivity, increasing contrast, or accelerating development. The developing agent may include compounds, urethane derivatives, urea derivatives, imidazole derivatives, and developing agents such as dihydroxybenzenes and 3-pyrazolidones. Among them, dihydroxybenzenes (hydroquinone, 2-methylhydroquinone, catechol, etc.) and 3-pyrazolidones (1-phenyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, etc.) are preferred. , usually used at 5 g/m ² or less. For dihydroxybenzenes, 0.01 to 1
g/m ² is more preferable, and in the case of 3-pyrazolidones, 0.01 to 0.2 g/m ² is more preferable. The photographic light-sensitive material used in the present invention may contain a dispersion of a water-insoluble or sparingly soluble synthetic polymer in the photographic emulsion layer or other hydrophilic colloid layer for the purpose of improving dimensional stability. For example, alkyl (meth)acrylate, alkoxyalkyl (meth)
Acrylate, glycidyl (meth)acrylate, (meth)acrylamide, vinyl ester (e.g. vinyl acetate), acrylonitrile, olefin, styrene, etc. alone or in combination, or together with acrylic acid, methacrylic acid, α,β-unsaturated dicarboxylic acid, Hydroxyalkyl (meth)
Polymers containing a combination of acrylate, sulfoalkyl (meth)acrylate, styrene sulfonic acid, etc. as monomer components can be used. The photographic emulsions used in the present invention may be spectrally sensitized with methine dyes and others. The pigments used include cyanine pigments, merocyanine pigments,
Included are complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes, and complex merocyanine dyes. Any of the nuclei commonly used for cyanine dyes can be used as the basic heterocyclic nucleus for these dyes. That is, pyrroline nucleus, oxazoline nucleus, thiazoline nucleus, pyrrole nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus, imidazole nucleus, tetrazole nucleus, pyridine nucleus, etc.; a nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei; and these A nucleus in which an aromatic hydrocarbon ring is fused to the nucleus of Imidazole nuclei, quinoline nuclei, etc. can be applied.
These nuclei may be substituted on carbon atoms. The merocyanine dye or composite merocyanine dye includes a nucleus having a ketomethylene structure, such as a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thioxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus, A 5- to 6-membered heteroartic ring nucleus such as a thiobarbituric acid nucleus can be applied. The photographic light-sensitive material of the present invention may contain an inorganic or organic hardening agent in the photographic emulsion layer or other hydrophilic colloid layer. For example, chromium salts (chromium alum, chromium acetate, etc.), aldehydes (formaldehyde, glyoxal, glutaraldehyde, etc.), N-methylol compounds (dimethylol urea, methylol dimethylhydantoin, etc.),
Dioxane derivatives (2,3-dihydroxydioxane, etc.), active vinyl compounds (1,3,5-triacryloyl-hexahydro-s-triazine, 1,3-vinylsulfonyl-2-propanol, etc.), active halogen compounds (2,3-dihydroxydioxane, etc.), (4-dichloro-6-hydroxy-s-triazine, etc.), mucohalogen acids (mucochloric acid, mucophenoxychloroic acid, etc.), and the like can be used alone or in combination. (Examples) The present invention will be explained in detail below using Examples, but the present invention is not limited to these embodiments. Example 1 An emulsion consisting of cubic AgBrI (I; 1.0 mol%) grains with an average grain size of 0.6 μm prepared by a conventional method was subjected to chemical ripening, and a spectral sensitizing dye of the following structural formula: 0.30
Millimole/mol AgX was added to prepare a coating solution.

[Formula] 2.0g of silver and 4.0g of gelatin in 100g of this coating solution
After adjusting the gelatin concentration to contain
1 mg of 1-phenyl-5-mercaptotetrazole was added as an antifoggant, and the following method -
10g of the optical brightener emulsion prepared in 1 was added, and 0.2g of 2,4-dichloro-6-hydroxy-1,3,5 triazine was added as a hardening agent.
Thickness with protective layer consisting of gelatin 1.5g/ ^m2
110μ polyethine laminate paper (transmission density =
0.62) Coated on the support at a coated silver amount of 1.5 g/m ² .
Furthermore, Table 1 shows a dye emulsion prepared on the back side of the support as follows. Varying amounts were added to the back coating solution and applied. For comparison, we also prepared one without an optical brightener emulsion and a dye emulsion, one with an optical brightener emulsion introduced into the emulsion layer, and one with a protective layer of an emulsion layer containing an optical brightener emulsion. A sample to which a dye emulsion was added was also prepared as a comparison sample. The coated sample was processed without exposure to light under the conditions shown below, and the fluorescence intensity was measured using a Hitachi 203 fluorescence spectrometer. The same treated sample was measured using a Nippon Denshoku Kogyo color difference meter.
The lightness (L value) was determined using MODEL 1001DP, and the whiteness was visually evaluated, and the results are shown in Table 1. <Preparation of optical brightener emulsion> As an oil-soluble optical brightener, exemplified compound F-1,
A 12% aqueous gelatin solution containing 7 g of dodecylbenzenesulfonic acid as a solid content is obtained by dissolving 8 g of n-dioctyl phthalate in 100 ml of ethyl acetate and 200 ml of ethyl acetate.
The mixture was mixed with 800 ml at about 60°C and stirred vigorously using a homogenizer to prepare an emulsified dispersion. <Preparation of dye emulsion> A solution of 1.0 g of Exemplary Compound D-8 in 100 ml of cresyl phosphate and 80 ml of ethyl acetate contains 7 g of dodecylbenzenesulfonic acid as a solid content.
The mixture was mixed with 800 ml of a 12% aqueous gelatin solution at about 60°C and stirred vigorously using a homogenizer to prepare an emulsified dispersion. <Development processing> Developer composition 1-phenyl-3-pyrazolidone 0.4g Sodium sulfite (anhydrous) 67g Hydroquinone 23g Potassium hydroxide 11g Sodium carbonate monohydrate 11g Potassium bromide 3g 5-Methyl-benzotriazole 133mg Add water Set to 1. Fixer composition Ammonium thiosulfate 170g Sodium sulfite (anhydrous) 15g Boric acid 7g Glacial acetic acid 5g Ethylenediaminetetraacetic acid 0.1g Add water to make 1. Processing conditions Using the processing solution with the above composition, development was carried out in a small self-developing machine under the following conditions: development at 30°C for 25 seconds, fixing at 30°C for 25 seconds, washing with water at 20°C for 25 seconds.

[Table] As can be seen from Table 1, when a dye is used on the optical brightener side, the whiteness becomes insufficient and becomes dark, and the brightness and fluorescence intensity are inferior, whereas in the present invention, a dye is used on the back side. As a result, brightness and fluorescence intensity were high, and satisfactory whiteness was obtained. Example 2 Example 1 was carried out in exactly the same manner as in Example 1, except that the same amount of Exemplary Compound D-9 as in Example 1 was used as the dye in the dye emulsion. The results are shown in Table-2. As shown in Table 2, samples 2-5 and 2-6, which are embodiments of the present invention, are superior even when the dyes are changed.

[Table] Example 3 In Example 1, the amount of dye added and the transmission density of the supports were determined as shown in Table 3 in the same manner as in Example 1, using supports with different transmission densities. The results are shown in Table-3. In sample 3-8, where the transmission density of the support was 1.02, it was necessary to increase the amount of dye added, and in this case, the back side would have a strong bluish feel, which is not preferable. It can be seen that samples 3-4 to 3-6, which are included in the embodiments of the present invention, are excellent in both brightness and whiteness.

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Claims (1)

[Claims] 1. Photographic paper having a silver halide emulsion layer on a reflective support, the reflective support having a transmission density of 0.8 or less, and containing a fluorescent brightener in the silver halide emulsion layer on the support, A silver halide photographic paper further comprising a silver halide emulsion layer and an oil-soluble dye on the opposite side of the support.