JPH03182741A - Silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE:To improve the sharpness of images by laminating synthetic resin layers on both surfaces of a specific paper base and dispersing white pigments into the synthetic resin layer on the side where an emulsion is coated. CONSTITUTION:The synthetic resin layers are laminated on both sides of the paper base and the white pigments are dispersed into the synthetic resin layer on the side where the emulsion is coated. The photosensitive material is so formed as to have >=2.9 optical density of the light escaping to the rear surface when measured by a goniophotometer while the paper itself is about 150mu thick and to have >=3.0 optical density of the light escaping to the rear surface of the base formed by using this paper. Namely, the synthetic resin layers are satisfactory if the layers allow the dispersion of the white pigments, can be laminated on paper by melt extrusion, etc., and can prevent the penetration of water and photographic processing liquid. The good curling balance is obtd. and the color development with excellent sharpness is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a silver halide photographic material, and more particularly to a reflective silver halide photographic material with improved image sharpness.

[Conventional technology]

The sharpness of silver halide photographic light-sensitive materials is determined by so-called irradiation, where incident light is scattered by silver halide particles, particles of emulsified dispersions such as couplers and UV absorbers, and certain filler particles contained in the light-sensitive element. It is well known that the optical density decreases due to gelation or due to so-called halation, in which light is reflected by a support located below the photosensitive element. In order to prevent irradiation, it is common practice to add a dye to the silver halide emulsion layer. Regarding prevention of halation, for example, JP-A-5E160
No. 738 describes the provision of a colorant-containing layer that becomes substantially colorless upon treatment between a support and a white pigment-containing layer in which a white pigment is dispersed in a water-soluble binder. Adding dyes to prevent irradiation has the disadvantage of reducing the sensitivity of silver halide photographic light-sensitive materials, and the use of a white pigment-containing layer in which white pigments are dispersed in a water-soluble binder is used in light-sensitive elements. Areas that have been subjected to stress such as bending or scratching may develop color when developed, and the amount of processing liquid components absorbed into the photosensitive element is greater than in a system without a core layer, making staining more likely to occur during print storage. , secondary problems such as loss of curl balance occur.

[Problem to be solved by the invention]

Therefore, there is a need for a reflective silver halide photographic material that is free from such secondary problems and has excellent image sharpness. As mentioned above, image sharpness is affected by various factors, but it has been found that it is also reduced by light scattering in the support.

Generally, the support is often thicker than the photosensitive layer coated thereon, and therefore, there is a great possibility of improving the sharpness of the image by considering the support. It has been found that the sharpness of the image decreases because light incident from the emulsion layer side is scattered in the support and returns to the emulsion layer.

Paper occupies a large proportion of the thickness of the support, and it is desirable to minimize the amount of light scattered inside the paper returning to the emulsion layer. In other words, if the incident light is reflected as close to the surface of the synthetic resin layer containing the white pigment and the paper as possible, there is a great possibility that the sharpness can be improved.

By increasing the amount of white pigment dispersed in the synthetic resin layer, the proportion of incident light reflected at the upper layer of the support is increased, and the proportion of reflection inside the paper is reduced, improving sharpness. However, if the amount of white pigment added to the synthetic resin layer is increased, the flatness of the support will be significantly reduced, and the speed of the process of laminating the paper and synthetic resin layer will have to be reduced. Therefore, the amount of white pigment added is restricted.

By adding a white pigment such as titanium white to the paper or coating the paper with a white pigment such as titanium white dispersed in a water-soluble polymer such as gelatin, the proportion of incident light reflected near the surface of the paper can be increased. It is possible to reduce the proportion of reflection inside the paper by increasing the amount of white pigment, but in this case, there are restrictions on the amount of white pigment added and the amount of coating applied due to the ease of handling the paper and the suitability of the synthetic resin layer for carving. be.

[Means to solve the problem]

It is very difficult to quantitatively evaluate how the incident light is reflected in the thickness direction of the support (the inventor has not found a way to do so, but for example, it is difficult to quantitatively evaluate how the incident light is reflected in the thickness direction of the support). Qualitative inferences can be made by measuring the optical density distribution on the front and back sides of the body using a goniophotometer. The fact that a large amount of light passes through the back side of the support means that there is a high probability that the light will be reflected deep within the support.

As a result of various studies from the above point of view, the present inventor found that when the thickness of the support itself is approximately 150 μm, the thickness of the support is approximately 5° When light is incident at an angle of A photographic light-sensitive layer is coated on a support that has an optical density of 2.9 or more and the optical density of light passing through the back surface of a support formed using this paper is about 3.0 or more, and is exposed and developed. It has been found that the resolution of the images obtained can be improved.

That is, the present invention provides a silver halide photographic light-sensitive material having at least one silver halide emulsion layer on a paper support, in which synthetic resin layers are laminated on both sides of the paper support and the emulsion is coated on the side on which the emulsion is applied. A white pigment is dispersed in the synthetic resin layer, and when the paper itself is about 150μ thick, the optical density of light passing through the back surface is 2.9 or more when measured with a goniophotometer. The silver halide photographic material is characterized in that the optical density of light passing through the back surface of the support is 3.0 or more.

The present invention will be explained in detail below.

Generally, the larger the optical density value of the back side of a paper support, the less light passes through to the back side.

Even if the paper is of the same thickness, the thicker the paper, the higher the optical density value on the back side, so the paper thickness must be kept the same for measurement.

The synthetic resin layer in the present invention may be any material as long as it can disperse a white pigment, can be laminated onto paper by melt pressing, etc., and can prevent penetration of water or photographic processing liquid, such as a film made of polyolefins, especially polyethylene. .

In the present invention, examples of the white pigment added to the synthetic resin layer on which the emulsion is applied include titanium dioxide (titanium white), zinc oxide, barium sulfate, silica, alumina, and barium stearate. Titanium is preferred, and may be of anatase type or rutile type. A white pigment is added so that the reflectance of the support is 80% or more at 380 to 700 nm. The preferred thickness of the synthetic resin layer is 25 to 40μ, and the preferred amount of white pigment added is 8
~20g/bo.

The light-reflecting substance to be dispersed in the synthetic resin layer of the support is preferably prepared by sufficiently kneading a white pigment in the presence of a surfactant, and by treating the surface of R coarse particles with a di- to tetrahydric alcohol. It is preferable to use

The occupied area ratio (%) of white pigment fine particles per defined unit area is most typically calculated by dividing the observed area into adjacent 6 n x 6 n unit areas and projecting onto that unit area. It can be determined by measuring the occupied area ratio (%) (Ri) of the fine particles.

The coefficient of variation of the occupied area ratio (%) is the average value of R4 (1'
It can be determined by the ratio S/l'r of the standard deviation S of R4 to r). Number of target unit areas (n)
is preferably 6 or more. Therefore, the coefficient of variation s/W can be determined as follows.

In the present invention, the coefficient of variation of the occupied area ratio (%) of the pigment fine particles is preferably 0.15 or less, particularly 0.12 or less. If it is 0.08 or less, the dispersibility of the particles can be said to be "substantially uniform."

The paper is made by adding a white pigment such as titanium dioxide so that the optical density on the back side is approximately 2.9 or higher when measured with a goniophotometer, or by adding a white pigment such as titanium dioxide to a water-soluble polymer such as gelatin. Use a pigment that has been dispersed and applied.

The preferred thickness is approximately 150 μm, but depending on the application, it may be thinner than this as long as the optical density of the back surface is approximately 2.9 or more in terms of 150 μm. If it is thicker than 150μ, the apparent value will be larger because it should be about 2.9 or more when converted to 150μ.

A subbing layer is generally coated on the white pigment-containing synthetic resin layer on the side to which the photographic emulsion layer is coated.

Moreover, a so-called c-king layer may be coated on -E of the synthetic resin layer on the opposite side in order to balance the curl, provide writability, and prevent static.

The paper used for the support of the present invention is selected from materials commonly used for photographic paper, such as those obtained from natural bulbs, synthetic pulps, or mixtures thereof. That is, the main raw material is natural bulbs selected from conifers, hardwoods, etc., and as necessary, fillers such as clay, talc, calcium carbonate, urea resin fine particles, rosin, alkyl ketene dimer, higher fatty acids, paraffin wax, alkenyl succinic acid, etc. A material containing a sizing agent such as epoxidized fatty acid amide, a paper strength agent such as polyacrylamide, a fixing agent such as sulfuric acid, or a cationic polymer may be used. In particular, neutral paper with a pH of 5 to 7 (measured with a pH meter using a flat model GST-5313F manufactured by Toa Denpa Kogyo Co., Ltd. as an electrode) using a reactive sizing agent such as alkyl ketene dimer or alkenyl succinic acid. The one used is preferred. Furthermore, synthetic pulp may be used in place of the above-mentioned natural pulp, or a mixture of natural pulp and synthetic pulp in any ratio may be used.

The surface of the valve can also be surface-sized with a film-forming polymer such as gelatin, starch, carboxymethyl cellulose, polyacrylamide, polyvinyl alcohol, or a modified product of polyvinyl alcohol. Examples of polyvinyl alcohol modified products in this case include carboxyl group modified products, silanol modified products, and copolymers with acrylamide. Further, when surface size treatment is performed using a film-forming polymer, the coating amount of the film-forming polymer is adjusted to 0.1 to 5.0 g/po, preferably 0.5 to 2° Og/rrf. Furthermore, an antistatic agent, a fluorescent whitening agent, an antifoaming agent, etc. can be added to the film-forming polymer at this time, if necessary.

In addition, the paper used in the present invention is produced by processing pulp that has reached -E and valve slurry containing additives such as filler, sizing agent, paper strength reinforcing agent, and fixing agent as necessary by a paper machine such as a Fourdrinier paper machine. It is manufactured by making paper, drying, and winding. The above-mentioned surface size treatment is performed sometime after this drying step 111, and calender treatment is performed after drying and between winding. If the surface size treatment is performed after drying, this calender treatment can be performed either before or after the surface size treatment.

The silver halide in the silver halide emulsion layer coated on the reflective support used in the present invention is silver chloride, silver bromide, silver chlorobromide, or a mixture of these and silver iodide. is used, and may be either a surface latent image type or an internal layer image type.

For the photosensitive material of the present invention, it is particularly preferable to use a high silver chloride emulsion with a silver chloride content of 80 mol % or more and a non-diffusible hydrophobic color coupler.

Regarding the preferred halogen composition, grain structure and manufacturing method of such high silver chloride emulsions, see European Patent EPO, 273,430.
Those described on pages 3 to 31 of A2 and in Examples can be applied.

Further, for couplers and other photographic additives, those described on pages 32 to 51 of the above-mentioned European patent can be applied, and for color processing, the methods and methods described on pages 51 to 57 of the above-mentioned European patent can be applied. In addition, these silver halides,
Regarding photographic additives and color processing, please refer to Japanese Patent Application No.
The one described in '168895 can be preferably applied.

The optical properties of the gill and the support were measured using an automatic variable angle photometer (GON IOPI) manufactured by Murakami Color Research Institute (Tokyo).
When data obtained by measurement using an IOTOMETER is graphed, a diagram such as that shown in FIG. 1 is obtained, for example. FIG. 1 is a graph obtained by measuring the optical properties of the sample $4A support of Example 1 using an automatic variable angle photometer, and the sample measured in the figure connects 90° and 270°. It is placed on the horizontal line, and light is applied from a direction (arrow) at 5 degrees to the normal line drawn to the front surface of this sample, and how the light is distributed over 360 degrees is depicted. Concentric circles centered on the origin represent the degree of brightness of light (equal optical density), the circle with D = 0.0 is the brightest, and the circle with D = 2
．． A circle of 0 represents medium brightness and D = 4.0 represents the darkest.

A large optical density value means that less light passes through that area. The center of the concentric circles has an optical density of 4.0 (Due to the accuracy of the detector, it is impossible to distinguish between 4.0 and above.) The curve above the horizontal axis passing through the center is reflected by the surface of the support (emulsion layer coating side). The curve below the horizontal axis represents the brightness of light passing through the back side of the support.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 Samples A and B were prepared in which all other constituent layers were the same except for the support.

Support for Sample A A paper with a thickness of approximately 150μ and an optical density of 2.5 measured with a goniophotometer was used as a support for comparison, and anatase type titanium white was used on the side of this paper where the emulsion was coated. The other side was coextrusion laminated with polyethylene containing 10% by weight of titanium white dispersed therein and polyethylene containing no titanium white on the other side. The thickness of the polyethylene layers is 30μ each. The optical density of the back surface of this laminated support was measured with a goniophotometer and was 2.7.

Support for Sample B: Paper containing 30% by weight of anatase-type titanium white and having an optical density of 3.1 on the back surface as measured by a goniophotometer and a thickness of approximately 150μ was used. Same as the support. The optical density of the back surface of this laminated support was measured with a goniophotometer and was 3.4.

A multilayer color photographic paper having the layer structure shown below was prepared on the paper support. The coating solution was prepared as follows.

19.1 g of yellow coupler (Ext), 4.4 g of color image stabilizer (Cpd, 1) and color image stabilizer (C
pd-7) 27.2 cc of ethyl acetate and 8.2 g of solvent (Solv-1) were added to 0.7 g and dissolved, and this solution was mixed with 8 c of 10% sodium dodecylhenzenesulfonate.
The mixture was emulsified and dispersed in 185 cc of a 10% aqueous gelatin solution containing c. On the other hand, silver chlorobromide emulsion (cubic, average grain size 0.
3=7 mixture of 88- and 0.70μ (silver ratio). The coefficient of variation of particle size distribution is 0.08 and 0.08.
10. Each emulsion contains 0.2 mol % of silver bromide locally on the grain surface), and the following blue-sensitive sensitizing dyes are added per mol of silver to 2.0 x 10-' mol for large-sized emulsions, respectively. In addition, for small size emulsions, 2.5X
After adding 10-' moles, sulfur sensitization was applied to 'gA.
Manufactured.

The above-mentioned emulsified dispersion and this emulsion were mixed and dissolved to prepare a first coating liquid so as to have the strength shown below.

Coating solutions for layers 2 to 7 were also prepared in the same manner as coating solution No.-N. As the gelatin hardening agent for each layer, 1-oxy-3,5-dichloro-3-triazine sodium salt was used.

The following spectral sensitizing dyes were used in each layer.

Blue sensitive emulsion layer SOiθ SO+tl-N(Calls):+ (C11□).

(CL)4 SO1θ SOJ! l (C2tls) 3 (2.0XIO-'mol each for large size emulsions and 2.5XIO-'mol each for small size emulsions per mole of silver halide) green-sensitive emulsion layer (halogen 4.0 x 10-' moles for dog size emulsions and 5.6 moles for small size emulsions per mole of silveride.
XlO-' mol) and SO, θ 03H N(CJs)x (halogenated! per 11 mol, 7.0 mole) Red-sensitive emulsion layer CzHs lθ C21 ((per mole of silver halide, for large size emulsions 0.9XIO-
'molar, and 1.0 molar for small size emulsions. lX10-'
mol) To the red-sensitive emulsion layer, the following compound was added in an amount of 2.6 x 10-' mol per mol of silver halide.

In addition, 1-(5~methylureidophenyl)5-mercaptotetrazole was added to each of the blue-sensitive emulsion layer, green-sensitive emulsion layer, and red-sensitive emulsion layer with halogenated S! 8 moles per mole
．． 5 x 10-s mol, 7.7XIO-' mol, 2.5X
10-'mol was added.

In addition, 1X10-' mol and 2XIO-' mol of 4hydroquine-6-methyl-1,3,3a7tetrazaindene were added to the blue-sensitive emulsion layer and the green-sensitive emulsion layer, respectively, per mol of halogenated compound. .

The following dye T4 was added to the emulsion layer to prevent irradiation.

and (layer structure) The strings for each layer are shown below. The numbers represent the coating amount (g/rd). The silver halide emulsion represents the coated amount in terms of silver.

Support polyethylene laminate paper [The polyethylene on the first layer side contains a white pigment (TiO□) and a bluish dye (ulmarine blue)] Part-II (blue-sensitive layer) Said silver chlorobromide emulsion 0.30 Gelatin 1.86 Yellow coupler (ExY) 0.82 Color image stabilizer (Cpd-1) 0.19 Solvent (Solv-1) 0.35
Color image stabilizer (Cpd-7) 0.
06 Second layer (color mixing prevention layer) Gelatin 0.99 Color mixing prevention agent (Cpd-5) 0.08 Solvent (Solv-1) 0.1
6 solvent (Solv-4>0
．． 08 Third layer (green-sensitive layer) Silver chlorobromide emulsion (cubic, 1:3 mixture (Ag molar ratio) of one with an average grain size of 0.55μ and one with an average grain size of 0.39n. Coefficient of variation of grain size distribution are 0, 10 and 0.08,
(Each emulsion contained 8 mol% of AgBrO locally on the grain surface) 0.12 Gelatin
1.24 magenta coupler (ExM)
0.20 color image stabilizer (Cpd-2)
0.03 color image stabilizer (Cpd-
3) 0.15 color image stabilizer (Cp
d-4) 0.02 color image stabilizer (
Cpd-9) 0.02) Container (
Solv-2) 0.40 Fourth layer (ultraviolet absorption layer) Gelatin 1.58 Ultraviolet absorber (UV-1) 0.47 Color mixture prevention agent (Cpd-5) 0.0
5 Solvent (So!v-5) 0
．． 24 Fifth layer (red-sensitive layer) Silver chlorobromide emulsion (cubic, 1:111 mixture of one with an average grain size of 0.58μ and one with an average grain size of 0.45n (Ag molar ratio). Grain size distribution The coefficient of variation is 0.09 and 0.1
1. In each emulsion, 6 mol% of AgBr O was locally contained in a part of the grain surface) 0.23 Gelatin
1.34 cyan coupler (E
xC) 0.32 color image stabilizer (C
pd-6) Color image stabilizer (Cpd-7> Color image stabilizer (Cpd-8) Solvent (Solv-6) Sixth layer (ultraviolet absorption N) Gelatin ultraviolet absorber (UV-1) Color mixing prevention agent (cpd -5) Solvent (Solv-5) Seventh N (1iN) Gelatin 1.33 Acrylic modified copolymer of polyvinyl alcohol (denaturation degree 17%
) 0.170.03 0.17 0.40 0.04 0.15 0.53 0.16 0.02 0.08 Liquid paraffin (Ext) 1 1 mixture with yellow coupler Ct It s (molar ratio) ( ExM) 1:l mixture (molar ratio) of magenta couplers (ExC) Cyan couplers R-CJs and CJ.

and 1 Each weight is 2: :Mixture of 4 (Cpd 1) color image stabilizer (Cpd-2) color image stabilizer しυυしtlls (Cpd-3) color image stabilizer (Cpd-4) color image stabilizer (Cpd-5) Color mixing prevention agent 0 ■ H (Cpd-6) color image stabilizer shiaHq tano 2 : 4 Mixture (weight ratio) (Cpd-7) color image stabilizer →C1h-CHh- CONHC4H9(t) Average molecule l 60.000 (Cpd-8) color image stabilizer H (Cpd-9) color image stabilizer Shinko Shinko (tlV-1) Ultraviolet absorber C,H (0 C, IIq(t) c4Hq(t) 4 4 combination (weight ratio) (Solv 1)? capacity Medium (Solv-2)? capacity Medium 2: ■Mixture (volume ratio) (Sol Sea 4) Sol Medium (Solv-5) Melt Medium C00CJ+7 (CHHz)s C00CJ+.

(Solv-6) The method for evaluating the sharpness of solvent photographic light-sensitive materials is described in detail in "Basic Silver Salt Photography of Photographic Engineering, p. 418 (Complete Edition of Nippon Photo Studio)".

1. Samples A and B were exposed to light through red, green, and blue optical filters with a rectangular wave mask having various spatial frequencies in close contact with them.

The exposed sample was processed in the following steps using a paper processing machine.

Treatment 1 King Law Benefit-1--degree Output Color Development
Bleach and fix at 35°C for 45 seconds Rinse at 30-35°C for 45 seconds ■ Rinse at 30-35°C for 20 seconds ■ Rinse at 30-35°C for 20 seconds ■ Dry at 70-80°C for 60 seconds (rinse ■-・■ The composition of each treatment liquid is as follows.

Ya-Lannyffl (l-i
j Otsu−2□22Δ(capture=namie [water
800 ail
800 rtdl Ethylenediamine-NN NN-tetramethylenephosphonic acid 1.5 g 2.0 g
Potassium bromide 0.015 g Triethanolamine 8.0 g 12.0 g Sodium chloride 1.4 g Potassium carbonate 5 g N-ethyl-N-(β-methanesulfonamidoethyl)-3-methyl-4 Aminoaniline sulfuric acid Salt 5゜Og N,N-bis(carboxinmethyl)hydrazine 5.5g Fluorescent brightener (WIIITEX 4B, manufactured by Sumitomo Chemical) 1.0 g Add water] 000ml pH (25°C) 10.05 jlfl- Redundant IL (Tank fluid and refill fluid are the same) Ammonium hydrothiosulfate (70%) Sodium sulfite Iron ethylenediaminetetraacetate (I[I) Ammonium ethylenediaminetetraacetate disodium Ammonium bromide 5 g 7.0 g 7.0 g 2 .0g 000if 10.45 400 ml 100 ml 7 g 5 8 g 0 g Add water and make 1000 rrdl pl ((25°C)) 6.0 421 waves (tank liquid and replenisher liquid are the same) Ion exchange water (calcium , magnesium is 3 p each
PII+ or below) Sharpness is 4, 10, and 15 lines/m+ for spatial frequencies, respectively.
0CTI with n/'! Evaluation was made using the value of output power contrast/power power contrast ratio).

The larger the number 4ti, the higher the sharpness.

It can be seen that aK $4 A, which has a large value of optical density of light passing from the front side to the back side of the paper, improves sharpness.

Example 2 Trials 14c and D were prepared in which all the other constituent layers were the same except for the support.

Support for Sample C A paper with a thickness of about 150 II and an optical density of 2.6 as measured by a goniophotometer on the back side was used as a support for comparison. The other side was coextruded laminated with polyethylene containing 15% by weight of Titanium White 1 dispersed therein and polyethylene containing no titanium white on the other side. The thickness of the polyethylene layers is 32μ each. The optical density of the back surface of this laminated support was measured with a goniophotometer and was 2.8.

Support for Test HD Samples except that paper with a thickness of approximately 150μ and an optical density of 2.9 on the back side measured with a goniophotometer were used, which were made by rinsing anatase-type titanium white at 15% by weight of the paper. Same as support in C. The optical density of the back surface of this laminated support was measured with a goniophotometer and was 3.1.

A photosensitive element was coated on the support in the same manner as in Example 1, and exposed and developed in the same manner as in Example 1.

Table 2 Sharpness It can be seen that the sharpness can be improved when the optical density of light passing from the front side to the back side of the paper is large.

(Effects of the Invention) When using the paper support specified by the present invention, color development with good curl balance and excellent sharpness can be obtained.

[Brief explanation of drawings]

FIG. 1 is a graph obtained by measuring the optical characteristics of the sample of Example 1 using an automatic variable angle photometer.

Claims (1)

[Claims] In a silver halide photographic material having at least one silver halide emulsion layer on a paper support, synthetic resin layers are laminated on both sides of the paper support, and the synthetic resin layer on the side to which the emulsion is coated has a white color. Pigments are dispersed, and the paper itself is approximately 15
The optical density of the light passing through the back side of the paper support formed using this paper is 3.0 or more, and the optical density of the light passing through the back side when measured with a goniophotometer when the paper is 0μ thick is 2.9 or more. A silver halide photographic material characterized by: