JPH02259751A - silver halide photographic paper - Google Patents

Abstract

PURPOSE:To enhance the whiteness of the white ground of a reflective support having a prescribed transmission density by forming an emulsion layer contg. a fluorescent whitening agent on the support and by incorporating an oil soluble dye into a layer on the rear side of the support. CONSTITUTION:A silver halide emulsion layer contg. a fluorescent whitening agent, e.g., a compd. represented by formula I is formed on a reflective support having <=0.8 transmission density, e.g., PE laminated paper and an oil soluble dye, e.g., an anthraquinone compd. represented by formula III is incorporated into a layer on the rear side of the support. In the formula I, each of Y1 and Y2 is alkyl and each of Z1 and Z2 is H or alkyl. A compd. represented by formula II may be used as the whitening agent represented by the formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a silver halide photographic paper with improved whiteness of a thin photographic paper. This invention relates to a technique for improving whiteness by including an oil-soluble fluorescent agent in an emulsion layer and using an oil-soluble dye on the opposite side.

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 optical brightener.

A method is known in which a fluorescent brightener is added in advance to a developing solution. 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 and printing processes during layer formation, and if optical brighteners are applied during the development process, they are constantly exposed during processing. It is most preferable to include a fluorescent brightener in the photographic layer in advance, as there are disadvantages such as the inability to maintain a uniform finish unless some effort is made to maintain a constant density. 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 such purposes, it is effective to incorporate nine oil-soluble optical brighteners into the gelatin layer as described in British Patent No. 1,072,915, dissolved in an organic solvent and added as an emulsified dispersion to the gelatin layer. method is known.

On the other hand, although visual whiteness varies depending on individual preference, it is also known that in general, bluish white looks whiter than 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 halogens. Residual colors caused by silver and dyes caused by fogging of silver emulsions, residual colors caused by sensitizing dyes and anti-irradiation dyes, dyeing of colored substances in processing machines, couplers, antioxidants, etc. that are a problem especially in color photographic paper, These include the yellowing caused by ultraviolet absorbers, and the formation of colored pigments by couplers and developing agents that occur without the development of silver halide. As a means for adjusting the hue, as seen in JP-A No. 53-19021, an inorganic coloring pigment is incorporated into the polyolefin of polyolefin coated paper to adjust the hue of the support surface;
As seen in Japanese Patent Application Laid-Open No. 55-93150, there is a known means for adjusting the hue in the photographic layer by using an oil-soluble dye in the photographic layer. Hue adjustment on the surface of a support involves the complexity of preparing the support depending on the optical properties of the various photographic layers, and extrusion coating of polyolefins is usually carried out at high temperatures of 300°C or higher. , the colorant is 3
It must satisfy requirements such as having heat resistance of 00℃ or higher, no bleed-out, no sublimation, and good dispersibility in polyolefins, and the range of colorant selection is narrow. In this respect, it is more advantageous to include the colorant in the middle of 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, white discoloration is improved by having an oil-soluble optical brightener and an oil-soluble dye present in different photographic layers, but even in this case, the whiteness of the dye can be adjusted by adjusting the whiteness. If the amount of addition is increased, there is a drawback that the brightness is decreased.

(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 This is achieved by containing an oil-soluble optical brightener in the silver halide emulsion layer and further containing an oil-soluble dye on the side opposite to the support.

As a result of our investigation, we found that using an oil-soluble fluorescent agent and an oil-soluble dye in the same emulsion layer as described in JP-A No. 60-154251 results in good white discoloration, but it is difficult to increase the amount of dye by adjusting the whiteness. Accompanied by a decrease in brightness.

However, it has been found that by using a dye on the back side of the support, the brightness decreases less and the whiteness improves.

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; When the transmission density is 0.8 or less, it is not affected so 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 means 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 whiteness 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. 786,234, and substituted thiophenes described in U.S. Patent No. 3,135.762 are useful. And, the special public official
Optical brighteners such as those disclosed in Japanese Patent Laid-open No. 5-37376 and Japanese Patent Application Laid-open No. 126732/1988 can be used with particular advantage.

Typically useful optical brighteners include those having one of the following structural formulas.

(U) 92 CIII) (■) z2 is hydrogen or an alkyl group, n is 〆 or 2, R1,
R2, R4 and R5 are aryl, alkyl, alkoxy, aryloxy, hydroxyl, amino, cyano, carboxyl, amide, ester, alkylcarbonyl,
It is an alkylsulfo or dialkylsulfonyl group or a hydrogen atom. R6 and R17 are a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, or a cyan group.

R16 is a phenyl group, a halogen atom, or an alkyl-substituted phenyl group. Rlg is an amino group or an organic or secondary amine.

Next, specific examples of water-insoluble optical brighteners used in the present invention will be given.

H2 H2 F-12 F-17 A method for preparing an emulsion of these water-insoluble optical brighteners is to dissolve the optical brightener in a high-boiling organic solvent as exemplified in British Patent No. 1,072,915. There is a method of emulsifying and dispersing this in a hydrophilic colloid such as gelatin together with a surfactant. Examples of high boiling point organic solvents include U.S. Patent No. 2,322,
No. 027, No. 3,676゜137, No. 3,779,7
No. 65, West German Patent No. 1.152.610, British Patent No. 1,
No. 272,561, JP-A-53-1520, JP-A-5
5-25057, Japanese Patent Publication No. 45-37376, etc., 7-talic acid esters and phosphoric esters are generally usable, but of course they are not limited to these; for example, U.S. Pat. The amide compounds disclosed in No. 416.923, benzoic acid esters, and substituted paraffins can also be used advantageously.

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, pluming will occur in areas of high image density, resulting in a decrease in the apparent image density. The luminous efficiency of fluorescence varies depending on the type of optical brightener, the type and concentration of oil used for emulsification, the coexistence of wood quenching substances, the coexistence of other ultraviolet absorbing substances, etc., so it cannot be expressed uniformly, but the present invention The amount of optical brightener used in
It is most preferable to use the range from 2009/- to 2009/-.

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 of the latex dispersion described in JP-A No. 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 7-mer 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 specific examples include anthraquinone-based, azo-based, phthalocyanine-based, oxonol-based, and benzylidene-based dyes. Among these, anthraquinone-based, azo-based and phthalocyanine-based dyes are particularly preferably used.

Next, a typical example will be shown.

2H5 0sNa Mixture of 5th and 8th positions D-9 D-18 CH7 The purpose of the dye used in the present invention is to adjust the hue of the white background of photographic paper. Depending on the degree and absorption characteristics, the one that looks the whitest visually should be selected. Is it possible to use two or more types of dyes together to improve their absorption characteristics? It can also be divided into sections. Although the content of the dye is not particularly limited, it is usually preferably 0.05 vv to 5 TIIg/m.

According to the present invention, since the reflective support used has a transmission density of 0.8 or less, the support can be made sufficiently thin.

In the present invention, as a reflective support, a transmission density of 0.8
Any reflective support can be used as long as it is as follows. 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.

The water-resistant surface in this case can be formed by coating a substrate, for example a paper substrate, with a hydrophobic resin.

In an embodiment in which such a water-resistant surface is formed, even when the 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, by extrusion coating a molten polyolefin onto a paper substrate to form a water-resistant surface, a polyolefin-laminated paper with excellent water resistance can be obtained.

Examples of the resin used for the hydrophobic resin coating layer on the surface include polyolefins such as polyethylene, polypropylene, and polybutene; olefins such as ethylene, propylene, and butene; examples include vinyl acetate, vinylidene chloride, maleic anhydride, etc. copolymer with nanatsumer (
(e.g., ethylene-vinyl acetate copolymer, propylene-vinylidene chloride copolymer, propylene-maleic anhydride copolymer, etc.), or homopolymers or copolymers such as polystyrene, polyvinyl chloride, polyacrylate, saturated polyester, polycarbonate, etc. polymer,
Or a blend of these substances can be mentioned. The thickness of this hydrophobic resin coating layer is not particularly limited, but is generally 10
The thickness is preferably about 50 μm.

When using a 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 BaSO4, ZnO, TiO2, etc. 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 then extruding or stretching to form voids and whitening, or by bonding them together.

As a binder or protective colloid that can be used in the emulsion layer or hydrophilic colloid layer (e.g., protective layer, intermediate layer) of the photosensitive material of the present invention, it is advantageous to use gelatin. Sex colloids can also be used.

Examples include 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,
Synthetic hydrophilic polymeric materials such as single or copolymers of polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, etc. can be used.

Gelatin includes lime-processed gelatin, acid-processed gelatin, Bull, Soc, Sci, Phot,
Japarx.

A16. 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 less than 15 moles of silver iodide. Particularly preferred is silver iodobromide containing from 2 to 12 moles of silver iodide.

Average grain size of silver halide grains in a photographic emulsion (grain diameter for spherical or approximately spherical grains, bag length for cubic grains, not based on projected area (expressed as average)) is not particularly limited, but it 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 particles.

The photographic emulsion used in the present invention is P, Glafkid
Chimie et Physique Pho by es
tographique (published by Pauli Monte 1,
(1967), Photo by G. F. Duffin
graphic Emulsion Chemjstr
y (The Focal Press, 1966)
, V. L., Zelikmanet al. Makf
ng and coating photography
icEmulsion (The Focal Pre
SS, 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 I-rogen salt may be one-sided mixing method, simultaneous mixing method, or a combination thereof. It's okay.

It is also possible to use a method in which particles are formed in an excess of silver ions (so-called back-mixing method).

As one type of simultaneous mixing method, a method in which the pAg in the liquid phase in which silver norogenide is produced can be kept constant, that is, a so-called Chondrald double jet method can 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.

Separately formed silver halide emulsions of 2 m or more may be mixed and used.

In the process of silver halide grain formation or physical release, cadmium salts, zinc salts, lead salts, thallium salts, iridium salts or complex salts thereof, rhodium salts or complex salts thereof, iron salts or iron complex salts, etc. may coexist. .

Silver halide emulsions are usually chemically sensitized.

For chemical sensitization, e.g. HoFrieser HA
l″Die Grundlagender Photo
graphischenProzesse mit S
ilber-halogeniden” (Akade
mische Verlagsgesellschaf
T, 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, Reduction sensitization method using amines, hydrazine derivatives, formamidine sulfinic acid, silane compounds): Noble metal compounds (e.g., total complex salts, Pt, I
A noble metal sensitization method using lead salts of metals of group 1 of the periodic table such as r, Pd, etc. 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, bromobenzimidazoles, mercaptothiazoles,
Mercaptobenzothiazoles, mercaptobenzimidazoles, mercap)? Asiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (especially 1-phenyl-5-mercaptotetrazole), etc.; mercaptopyrimidines; mercaptotriazines; thioketo compounds such as oxadorinthion Niazaindenes, such as triazaindenes, tetraazaindenes C% Ic 4-hydroxy substitution (is L 3a,
7) Adding a number of compounds known as anti-capri agents or stabilizers such as tetraazaindenes), pentaazaindenes; benzenethiosulfonic acid, benzenesulfinic acid, benzenesulfonic acid amide, etc. I can do it.

For more detailed examples of these and their uses and methods, see, for example, U.S. Pat.
Those described in No. 982,947 and Japanese Patent Publication No. 52-28,660 can be used.

The photographic emulsion layer or other hydrophilic colloid layer of the light-sensitive material prepared using the present invention may contain coating aids, antistatic properties, smoothness improvement, emulsification dispersion, adhesion prevention, and photographic property improvement (e.g.
Various surfactants may be included for various purposes such as development acceleration, high contrast, and sensitization.

For example, saponins (steroids), alkylene oxide conductors (e.g. polyethylene glycol, polyethylene glycol/volibrobylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or amides, polyethylene oxide adducts of silicone), glycidol derivatives (e.g. alkenyl; succinic acid polyglycerides, alkylphenol polyglycerides), fatty acid esters of polyhydric alcohols, alkyl esters of sugars, etc. Ionic surfactants; alkyl carboxylates, alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfates, alkyl phosphates, N-acyl-N-alkyl taurines, sulfosuccinic acid Carboxy groups such as esters, sulfoalkyl polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl phosphate esters,
Anionic surfactants containing acidic groups such as sulfo groups, phospho groups, sulfate ester groups, phosphate ester groups; amino acids;
Ampholytic surfactants such as aminoalkyl sulfonic acids, aminoalkyl sulfuric acid esters or phosphoric acid esters, alkyl betaines, and amine oxides; alkylamine salts, aliphatic or aromatic quaternary ammonium salts, pyridinium, imidazolium, etc. Cationic surfactants such as heterocyclic quaternary ammonium salts 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, thiomol 7-olins, quaternary ammonium salt compounds, urethane derivatives,
It may also contain developing agents such as urea derivatives, imidazole derivatives, dihydroxybenzenes, and 3-pyrazolidones.

Among them, dihydroxybenzenes (hydroquinone, 2
-methylhydroquinone, catechol, etc.) and 3-pyrazolidones (l-phenyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, etc.) are preferred, and usually 5 f/r? Used below. In the case of dihydroxybenzenes, 0.01
~1 fAI? is more preferable, and in the case of 3-pyrazolidones, 0.01 to 0.2 is more preferable.

The photographic light-sensitive material used in the present invention may contain a dispersion of a water-insoluble or water-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 these and acrylic acid, A polymer containing a combination of methacrylic acid, α, β-unsaturated dicarboxylic acid, hydroxyalkyl (meth)acrylate, sulfoalkyl (meth)acrylate, styrene sulfonic acid, etc. as a monomer component can be used.

The photographic emulsions used in the present invention may be spectrally sensitized with methine dyes and others. The dyes used include cyanine dyes, merocyanine dyes, 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, viroline nucleus, oxazoline nucleus, thiazoline nucleus, virol nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus, imidazole nucleus, tetrazole nucleus,
Pyridine nucleus, etc.: Nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei; and nucleus in which an aromatic hydrocarbon ring is fused to these nuclei, i.e., indolenine nucleus, benzindolenine nucleus, indole nucleus, benz Oxadole nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, penzimidazole nucleus, quinoline nucleus, etc. are applicable. These nuclei may be substituted on carbon atoms.

Merocyanine dyes or composite merocyanine dyes include a pyrazolin-5-one nucleus, a thiohydantoin nucleus, and a 2-thioxazolidine-2 nucleus having a ketomethylene structure.
, 4-dione nucleus, thiazolidine-2,4-dione nucleus, thiazolidine-2,4-dione nucleus, and deoparbituric acid nucleus.

The photographic material of the present invention may contain an inorganic or organic hardener in the photographic emulsion layer or other hydrophilic colloid layer.

For example, chromium salts (chromium alum, chromium acetate, etc.)
, aldehydes (formaldehyde, cryoxal,
geltaraldehyde, etc.), N-methylol compounds (
dimethylol urea, methylol dimethyl hydantoin, etc.).

Dioxane conductors (2,3-dihydroxydioxane, etc.), active vinyl compounds (1,3,5-)lyacryloyl-hexahydro-5-)riazine, 1°3-vinylsulfonyl-2-propatol, etc.), active Halogen compounds (2,4-dichloro-6-hydroxy-3-triazine), mucohalogen acids (mucochloric acid, mucophenoxychlorate), and the like can be used alone or in combination.

(Example) The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these embodiments.

Example 1 Cube A with an average grain size of 0.6 μm prepared by a conventional method
An emulsion consisting of gBr I (I: 1.0 mol%) grains was subjected to chemical ripening, and a spectral sensitizing dye of the following structural formula was added to the emulsion.
30 mmol 1 mol AgX was added to prepare a coating solution.

Silver 2. O? , gelatin 4.02
After adjusting the gelatin concentration, 1-phenyl-5-mercaptotetrazole 11% F was added as an antifoggant, and an optical brightener emulsion prepared according to method 1 below was added to 10% F. Added as a hardening agent, 2
．． 0.22% of 4-dichloro-6-hydroxy-1,3,5) riazine was added to 110μ thick polyethene laminated paper with a protective layer on the back of gelatin (1.5%).
Retraction degree = 0.62) It was coated on the support with a coated silver amount of 1.5. Furthermore, Table 1 shows a dye emulsion prepared on the back side of the support as follows. Varying amounts were added to the back metal 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 unexposed and processed under the conditions shown below.
Fluorescence intensity was measured with a Hitachi 203 fluorescence spectrometer.

The same processed sample was measured using a colorimetric color difference meter MODE made by Nihon Isshoku Kogyo.
The lightness (L value) was determined using L100IDP, and the whiteness was visually evaluated, and the results are shown in Table 1.

<Preparation of optical brightener emulsion> Exemplary compound F-1,8 as an oil-soluble optical brightener n
-100 d of dioctyl phthalate and 200 d of ethyl acetate
800 yd of a 12% aqueous gelatin solution containing dodecylbenzenesulfonic acid (solid content: 72%) and approximately 60°C.
and stirred thoroughly using a homogenizer to prepare an emulsified dispersion.

<Preparation of dye emulsion> Illustrative compound D-81, Of Cresyl 7Ospha) 1
A solution of 00g and 80g of ethyl acetate was heated at about 60°C with 800fnt of a 12tigelatin aqueous solution containing 7g of solid dodecylbenzenesulfonic acid, and stirred vigorously using a homogenizer to prepare an emulsified dispersion.

Development processing> Developer composition 1-Phenyl-3-pyrazolidone 0.4t Sodium sulfite (anhydrous) Hydroquinone Potassium hydroxide Sodium carbonate -water Potassium bromide 5-Methyl-benzotriazole Add water to 7t 11? 1P f 133 Cape 1t.

Fixer composition: Anthonium thiosulfate 170? Sodium sulfite (anhydrous) 15y boric acid
7f glacial acetic acid
5f ethylenediaminetetraacetic acid 0
．． Add 1f water to make 1t.

Processing conditions Using the treatment liquid with the above composition Development: 30℃, 25 seconds Fixing 30℃ 25 seconds Washing with water 20℃ 25 seconds The image was developed using a small self-developing machine that satisfies the following conditions.

As can be seen from Table 1, when a dye is used on the optical brightener side, the whiteness is insufficient and becomes dark, and the brightness and fluorescence intensity are inferior, whereas the use of a dye on the back side of the present invention results in brightness, Fluorescence intensity was high and satisfactory white discoloration was obtained.

Example 2 Example 11C was carried out in exactly the same manner as in Example 1, except that the same amount of Exemplified 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.

(The following is a blank space) Example 3 In Example-1, the amount of dye added and the transmittance density of the support were determined as shown in Table-3 in the same manner as in Example-1, using supports with different transmittance densities.

The results are shown in Table-3.

In sample 3-8 where the transmission density of the support is 1.02, it is necessary to increase the amount of dye added, and in this case, the back side becomes unfavorably bluish. 3-4 within the embodiments of the present invention
It can be seen that samples 3-6 are excellent in brightness and whiteness.

(Margin below)

Claims (1)

[Claims] (1) In a photographic paper having a silver halide emulsion layer on a reflective support, the reflective support has a transmission density of 0.
8 or less, and contains a fluorescent brightener in the silver halide emulsion layer on the support, and further contains an oil-soluble dye on the opposite side of the support from the silver halide emulsion layer. Chemical silver photographic paper.