JPH07107599B2 - Dot etching method for halftone silver halide images. - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a halftone silver halide image etching method and a silver halide photosensitive material for halftone (dot and line) image contact copying.

Prior Art Silver halide light-sensitive materials are commonly used in the photolithographic industry for producing halftone or line images, for example as color proofing films and contact printing papers.

For the purpose of adjusting the hue of the lithographic print, halftone dots or line images (usually the expression "halftone images" also includes "line images") partially dissolves the metallic silver of the halftone dots or line images. It is customary to carry out a treatment called "dot etching" which consists of a treatment with a mild oxidant solution of The most commonly used etching solution is a mixture of ferricyanide and thiosulfate, known as Farmer's solution, but other oxidizing agents such as permanganate, cerium salt, dichromate, Persulfates and the like can also be used.

In the case of halftone images, the loss of the silver image at the edges of the halftone dots varies from 0% to 100% halftone dot area ratio (ie covered by halftone halftone dots, % Of total area). The extent to which halftone dots can be etched is limited by the consequent loss of density at the center of the halftone dots during dot etching. The density at the center of the halftone dot should not drop below a value of 2 or else the quality of the copy or printing plate made from the original will deteriorate. The degree to which the film can be usefully etched should also be such that small halftone dots, i.e. 10% to 20%, should not be completely lost during the etching process and should remain large and dark enough to be copied. It is also limited by the so-called restraint. In order to improve the dot-etching properties of silver halide films used in photolithography, it is customary to increase the silver halide coverage. This method will reduce the concentration loss at the dot center during etching. However, the increased cost attributable to the increased silver coverage is a serious drawback. In addition, a very thick gelatin topcoat covering a silver halide emulsion is a method for improving the dot-etching characteristics of a photographic lithographic film as disclosed in British Patent 2,108,
No. 693. However, this method has the drawback that a substantial increase in gelatin content leads to an increase in the time required for post-treatment film drying.

SUMMARY OF THE INVENTION The present inventors have developed a halftone dot or line in which an imagewise exposed silver halide emulsion is developed in an alkaline developer and the silver image is dot-etched by a silver halide oxidizing solution. A method for improving photoengraving dot etching of a black-and-white silver halide light-sensitive material for image-contact copying, wherein the high chloride fine grain silver halide emulsion is at least 1 selected from the group of thiazolium salt compounds, thiazole compounds and pyrazole compounds. Used in operable combination with a compound of the invention (preferably in combination with a mercaptotetrazole compound), said at least one compound having a halftone dot area (especially 50% halftone intermediate size range such as halftone dots). However, there is a significant reduction in the dot area ratio of small dots (etching is actually the most harmful to small dots). There. Undesirable significant reduction of small halftone dots
10% halftone dot etching to less than 3%), and the improvement is characterized in that it is present in a reduced amount.

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the development of an imagewise exposed line or halftone image contact copying silver halide photosensitive material in an alkaline developer, the silver image of which is dot etched by a silver halide oxidizing solution. In the photoengraving dot etching method as described above, a high chloride fine grain silver halide emulsion is prepared from at least one selected from the group consisting of thiazolium (including dithiazolium) salt compounds, thiazole (including dithiazole) compounds, and pyrazole compounds. Operatively in combination with a compound, said at least one compound being used in an amount such that the area reduction of the dots takes place without significantly impairing the dot area ratio of the small dots. An improved method characterized by the following. As used herein, the term "high chloride" means a silver halide in which at least 60 mol% of its halide content is chloride ion. As used herein, the term "fine grain" refers to silver halide having an average grain size of less than 0.15μ.

Preferably, the invention relates to the above method wherein the selected compound is combined with a high chloride fine grain silver halide emulsion in combination with a mercaptotetrazole compound.

The following formulas (I), (II), (III), (IV) and (V)
Are provided to provide a better understanding of the chemical properties of the compounds of the present invention. The substituents attached to them have reasonable size and properties so as not to impair their utility as stabilizers, antifoggants, or toning agents used for the purposes of the invention. Should be.

In general, the thiazolium (including dithiazolium) salt compounds in the process of the invention correspond to general formula I or II: Wherein R ₁ represents hydrogen, a mercapto group, an aliphatic group, or an aromatic group; Q ₁ is selected from the group consisting of nitrogen and carbon atoms necessary to complete a single or fused 5-membered ring. Represents an atom; R ₂ represents an aliphatic group or an aromatic group, R ₃ represents a divalent group, and X ⁻ represents an anion. The mercapto group represented by R ₁ includes an alkylmercapto group such as methylmercapto, ethylmercapto and the like (wherein the alkyl substituent is preferably composed of 1 to 4 carbon atoms). Aliphatic groups represented by R ₁ and R ₂ include straight or branched chain alkyl groups, cycloalkyl groups, alkylene groups, and alkynyl groups. Examples of straight chain or branched chain alkyl groups are alkyl groups having 1 to 10, preferably 1 to 5 carbon atoms. Preferred examples include methyl, ethyl, propyl, butyl and the like. The cycloalkyl group generally has 3 to 10 carbon atoms, and preferred examples thereof are cyclopentyl group, cyclohexyl group, adamantyl group and the like. Examples of the alkenyl group are allyl group and the like, and examples of the alkynyl group are propargyl group and the like. The aliphatic group represented by R ₁ and R ₂ may be substituted. Examples of the substituent of the aliphatic group include an alkoxy group (for example,
Methoxy group, ethoxy group, propoxy group, butoxy group, etc.), one or more halogen atoms (eg chlorine, bromine,
Fluorine, iodine, etc.), alkoxycarbonyl group, aryl group (eg, phenyl group, halogen-substituted phenyl group, etc.), hydroxy group, cyano group, sulfonyl group, etc.

Examples of the aromatic group represented by R ₁ and R ₂ include a substituent (for example, an alkyl group, an alkoxy group, a cyano group, a dialkylamino group, an alkoxycarbonyl group, a carboxy group,
Nitro groups, alkylthio groups, hydroxy groups, sulfonyl groups, carbamoyl groups, halogen atoms and the like, the alkyl groups of which are preferably those having 1 to 5 carbon atoms) with or without phenyl and naphthyl groups. Preferred examples of the substituted group are, for example, p-methoxyphenyl group, o-
Methoxyphenyl group, tolyl group, p-chlorophenyl group,
Examples include m-fluorophenyl group and the like. The divalent group represented by R ₃ includes all divalent groups, but preferably 6 to
A cyclic hydrocarbon group such as an arylene group having 12 carbon atoms such as m-phenylene group, an alkylene group having 1 to 12 carbon atoms such as methylene group, ethylene group, trimethylene group, decamethylene group, etc. It is a non-cyclic hydrocarbon group. The divalent group represented by R ₃ is 8 to
It may be an aralkylene group having 10 carbon atoms. 1 to ₃ of the carbon atoms of the above groups for R ₃ can be replaced by heteroatoms such as nitrogen, sulfur, oxygen and the like. More preferably, R ₃ is a divalent branched or straight chain alkylene group having 1 to 10 carbon atoms. Such a chain is substituted with, for example, one or more of an alkoxy group having 1 to 4 carbon atoms such as a methoxy group and an ethoxy group, a halogen atom such as a chlorine atom and a bromine atom, a hydrogen atom, an acetoxy group and the like. be able to. The single or condensed 5-membered ring completed by Q ₁ in the above formula (I) is an alkyl group such as a methyl group or an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, a phenyl group or It may be substituted with an aryl group such as a benzine group, a halogen atom such as chlorine or bromine, an alkoxycarbonyl group, a cyano group, an amide group and the like. A ring fused onto a 5-membered ring is a single or fused 6-membered ring with or without one or more nitrogen atoms in its skeleton, eg benzene, | 1,2-d | or | 2,1-d | Or |
It may be 2,3-d | -naphthalene, 1- or 2- or 3-pyridine, pyridazine, pyrimidine, and pyrazine.

X ^- Examples of chlorine, iodine, nitrate, sulfate, p- toluenesulfonate and the like.

Further, in general, the thiazole (including dithiazole) compound of the present invention has the general formula (III) Wherein Q ₂ represents an atom selected from the group consisting of nitrogen and carbon atoms necessary to complete a single or fused 5-membered ring as described for the 5-membered ring of formula (I). , And R ₄ represents hydrogen, a mercapto group, and an aliphatic or aromatic group as described for R _{1 in} formulas (I) and (II).

Also, in general, the pyrazole compounds of the present invention have the general formula (IV) Wherein Q ₃ represents a single or fused ring as described for the 5 membered ring of formula (I).

Also, generally, the mercaptotetrazole compound to be combined with the above selected compound operatively associated with the high chloride fine grain silver halide emulsion according to the present invention is represented by the general formula (V) Wherein R ₅ represents an aliphatic or aromatic group as described for R ₁ and R _{2 in} general formula (I).

Preferably, according to the method of the present invention, the high chloride fine grain silver halide emulsion has an average grain size of less than 0.11μ (the term "grain size" as used herein refers to silver halide observed under an electron microscope). Means a circular diameter with the same area as the average projected area of the crystal). Still preferably, the high chloride fine grain silver halide emulsion according to the method of the present invention has a silver halide content of 80 mol% or more, more preferably 90% or more. Particularly preferred high silver chloride content emulsions are silver chlorobromide or silver chloroiodobromide emulsions. Also according to the method of the present invention, preferably the compounds selected from the above group and the combination of them with a mercaptotetrazole compound is from 0.01 to 2 g per mol of silver, more preferably from 0.05 to 0.5 g per mol of silver. A range of amounts is combined with the high chloride fine grain silver halide emulsion.

Another aspect of the present invention comprises one or more hydrophilic colloid layers coated on a support, at least one of which is a silver halide emulsion layer, and the silver halide emulsion is a thiazolium salt compound or thiazole. A black and white silver halide light-sensitive material for line or halftone image contact copying characterized in that it is a high chloride fine grain silver halide emulsion operably combined with a compound and a compound selected from the group of pyrazole compounds. Preferably, in the silver halide light-sensitive material of this invention, the selected compound is combined with a high chloride fine grain silver halide emulsion in combination with a mercaptotetrazole compound.

In general, thiazolium (including dithiazolium) salt compounds effective for the silver halide light-sensitive material of the present invention correspond to the above formulas (I) and (II). In general, a thiazole (including dithiazole) compound corresponds to the above formula (III). In general, the pyrazole compound has the above general formula (I
Equivalent to V). The compounds selected within the above formula are used to prepare the silver halide photosensitive material of the present invention.
It may be combined with a mercaptotetrazole compound corresponding to the general formula (V).

Such compounds, emulsion compositions, and grain sizes reduce the dot area ratio of 10% dots to less than 3% and also 100%.
50% halftone dot area ratio is more than 10% without reducing the halftone dot density below 2.0, preferably at least 12
It is specifically selected to reduce.

In fact, according to the present invention, the silver chloride content of the silver halide emulsion, the grain size of the silver halide grains, and the compounds (thiazolium salt compounds, thiazole compounds, and those selected from the group of pyrazole compounds, and the like) And the amount of the mercaptotetrazole compound) can be appropriately selected to obtain the best results.
In particular, the particle size has been found to have a significant effect on the above objectives. Of course, one of ordinary skill in the art can adjust the emulsion of the appropriate silver halide content, the grain size of the silver halide grains, and the amount of the selected compound to best operate the process according to the specific requirements. . To this end, standard halftone dot test charts can be used as described in the Examples below to control the results obtained while varying the specified parameters.

Furthermore, another invention relates to a dot-etched photograph produced by the above-mentioned dot-etching method.

Specific examples of the compounds corresponding to the above-mentioned general formula which are effective for the dot etching method and the silver halide photosensitive material of the present invention are as follows: Combined with the high chloride fine grain silver halide emulsions of this invention (the term "combined with" is added to the coating composition containing the silver halide emulsion used to form the silver halide emulsion layer. Or to be added to a silver halide emulsion-free coating composition that is used to form a water-permeable interrelated, non-photosensitive layer with the silver halide emulsion layer. When used), the compounds of general formulas I, II, III, and IV, alone or in combination with the compounds of general formula V, provide a significant improvement in the dot-etching properties of the coated emulsion. In particular, halftone dot sizes are greatly reduced without losing small dots and without reducing the density of large dots.

Organic sulfur compounds, especially thiols, are disclosed in, for example, Photographic Science and Engineering Vol. 11 (1967) p.363, Research Disclosure 1972.
It is well known to act as an inhibitor to bleaching silver images with a bleaching solution, as described in US Pat. No. 3,033,705,803.
This effect has been used, for example, to protect the silver optical soundtrack of motion picture films when bleaching metallic silver from color images. However, this effect is merely an overall suppression of bleaching, with bleaching of small dots (such as 10% halftone) to a greater degree than bleaching of midrange dots (such as 50% halftone). No signs of being suppressed. In fact, a 1-phenyl-5-mercaptotetrazole compound corresponding to compound 7 in the list above (which can suppress total bleaching as described in the above mentioned Photografic Science and Engineering). Known) are not effective on their own for the methods and materials of the present invention.

A number of heterocyclic nitrogen and sulfur compounds, including the compounds of the general structures I, II, III, IV and V above, were added to photographic emulsions by EJ Bar, "Stabilization of Stabilization.
It is also well known to produce a stabilizing or antifoggant effect as described in Chapter 3 of "Fotografic Emeraldion" (Foral Press, London, 1974).
This effect is generally independent of the type of halide present in the emulsion, as long as the dissociation constant of the stabilizer-silver ion complex is lower than the solubility product of silver halide. The antifoggant effect does not depend on the grain size of the silver halide emulsion. On the other hand, the improvement in the dot etching caused by the compound of the general formula I, II, III, or IV or the combination thereof with the compound of the general formula V is obtained for the fine silver halide emulsion containing a high% chloride. Seems to be special.

Further, many photographic stabilizers, including some of the compounds of Structures I, II, III, IV and V, have been added, especially when added to pure silver chloride emulsions, by P. Grafqueys in "Fotographik Chemistry" (Fauten. Press, London, 1958) 1st
It is known to modify the morphology of developed silver to impart a blue tone to the image, as described in Volume 380. Unlike the present invention, which requires a very fine grain emulsion, the image toning effect occurs regardless of the silver halide grain size.

The silver halide emulsions of this invention preferably have a narrow grain size distribution, but this invention is not limited to such emulsions. As noted above, the present invention is limited to very fine grain silver halide, with the major halide component being chloride and the minor component, if present, being either bromide or iodide, or both. . Emulsions of very fine grain size, such as those of the present invention, are often referred to as "lipman emulsions." Methods for producing such emulsions are well known, for example, P. Grafkays, "Photographic Chemistry" (Fountain Press, London, 1958), Vol. 1, Vol.
It is described on page 365.

Silver halide emulsions are gold compounds such as hydrochloroaurate and gold chloride; salts of precious metals such as rhodium and iridium; sulfur compounds capable of forming silver sulfide by reacting with silver salts; It may optionally be sensitized with reducing agents such as tin salts, amines and formamidine sulphinate. In addition, salts of noble metals such as rhodium and iridium may be present during precipitation or physical ripening of the silver halide emulsion. The binder for the emulsion is preferably gelatin, but some or all of it may be used for research purposes in order to improve the dimensional stability and physical properties of the coating film.
It may be replaced by other synthetic or natural polymers as described in Dice Closure, 1978, Section 17643, Section IX.

Suitable antifoggants or stabilizers may be added to the coating, for example as described in Research Disclosure Section VI above.

The emulsion may further contain additives such as wetting agents, hardeners, filter dyes, plasticizers, lubricants, matting agents, etc., as described in Research Disclosure above. In addition to the silver halide emulsion layer of the present invention coated on a support, the photosensitive material may have a non-photosensitive layer such as a surface protective layer, an antihalation layer, an antistatic layer and the like. The non-photosensitive layer may contain a hydrophilic colloid binder (eg gelatin), a surface active agent, an antistatic agent, a matting agent, a slipping agent, a gelatin plasticizer, polymalatex and the like.

Examples of supports preferably used in the photosensitive material of the present invention are polyester films such as polyethylene terephthalate film and cellulose ester films such as triacetic acid fibrous film.

The present invention does not particularly limit the development processing of the photosensitive material.
In general, all the development methods used in the lithographic field for processing photographic materials (consisting of the steps of developing, fixing and etching) can be employed. The developing process can be carried out manually or by using an automatic processor at a processing temperature generally in the range of 18 to 50 ° C., but a temperature outside the range is not excluded.

The developer can contain any of the known developers. Examples of developers (which may be used alone or in a mixture) are hydroxybenzene (eg hydroquinone), aminophenol (eg N-
Methyl-p-aminophenol), 3-pyrazolidone (eg 1-phenyl-3-pyrazolidone), ascorbic acid and the like. In addition, the developer may contain a preservative, an alkaline agent, a buffering agent, an antifoggant, a water softener, a hardener and the like.
The developers that can also be used in the present invention are called lith developers, which are dihydroxybenzene developing agents, alkaline agents, small amounts of free sulfite and sulfite ion buffers (eg formalin) for controlling the concentration of free sulfite. And sodium bisulfite adduct or acetone and sodium bisulfite adduct), and the like.

The fixer can have a composition that is commonly used. Examples of fixing agents that can be used are thiosulfates, thiocyanates, and organic sulfur compounds known as fixing agents. The fixing solution may further contain a water-soluble aluminum salt as a hardener.

In addition, the etching liquid contains all commonly used compositions,
For example, "The Theory of the Photographic Process" by CEK Meads (Macmillan, 1954).
It can have the composition described on pages 737-744. In detail, permanganate, ferric salt, persulfate, cupric salt, cerium salt, ferric hexacyano (II
I) Etching solution as a reducing component consisting of a salt or dichromate alone or optionally in combination with an inorganic acid such as sulfuric acid and an alcohol; or a hexacyanoferric (III) salt or ethylenediaminotetrahydrofuran Ferric acetate (I
II) An etching solution containing a reducing agent such as a salt, a silver halide solvent such as thiosulfate, thiocyanate, thiourea or a derivative thereof, and optionally an inorganic acid such as sulfuric acid. Can be used. Representative examples of the etching solution are a Farmer's solution containing potassium ferricyanide and sodium thiosulfate, an etching solution containing persulfate and potassium permanganate, an etching solution containing persulfate, and an etching solution containing cerium salt.

The composition of the etching liquid used in the present invention and the processing conditions (temperature, time, etc.) are not particularly limited. Etching the entire surface can be carried out by immersing the photosensitive material in an etching liquid as usual. Otherwise, the etching liquid may be applied locally, for example by using a brush, to etch a portion of the image.

Next, the present invention will be described in more detail with reference to examples.

Example 1 A silver halide emulsion containing 98% silver chloride and 2% silver bromide was prepared by an ordinary double jet method using an aqueous silver nitrate solution (800 m
l, 2.5N) and an aqueous solution of mixed halides (17 ml of 2.5N potassium bromide and 833ml of 2.5N potassium chloride) were added to a well-stirred aqueous gelatin solution at 36 ° C over 30 minutes. .

Lower the pH of the emulsion to 3.5 and add sodium sulfate (800 ml,
The emulsion was solidified by adding 40% w / v).
The emulsion was then washed in the usual way and reconstituted with the addition of additional gelatin to give a final content of 80 g gelatin / mol silver.

The average grain size of the emulsion was 0.080 by electron microscopy.
It was measured as μ. The emulsion was divided into several parts to prepare a coating material containing formaldehyde (hardener) and wetting agent.
In addition, the green antihalation layer was coated on the backed polyester base after each sample had the additions specified in Table 1. 10 for each cover
It was normally exposed through a standard halftone halftone dot test plate made with a Crossfield Laser-Skyana model 640 Magnaskyan consisting of 0 to 100% halftone dot area in% increments. The exposure light source is HP
It was an M17 metal halide lamp. The coating was developed with 3M RDC developer for 20 seconds at 40 ° C and fixed with a 3M "Fix Roll" fuser to produce a halftone image that was an exact negative reproduction of the test chart.

Cut the halftone halftone image to make a strip,
The strips were soaked in the ferricyanide bleaching solution for a series of times from 30 seconds to 6 minutes and then washed with water.

The ferrocyanide bleaching solution was prepared as follows: Solution A: Potassium ferriciyanide 37.5 g 500 cm ^{3 with} water Solution B: Sodium thiosulfate pentahydrate 480 g 2000 cm ^{3 with} water To use 1 part of solution A 4 And 27 parts of water. The temperature was kept at 20 ° C.

The strip was dried and the halftone dot area ratio of the bleached image was measured with a densitometer. The maximum etching ability of the coating is such that the measured area ratio of 10% halftone dot falls below 3%, or the density of 100% halftone dot is 2%.
It was grasped as the halftone dot reduction rate (%) that can be obtained for 50% halftone dots before either one falls below the other. Values for maximum etching capacity are given in Table 1.

The results shown in Table 1 show the effectiveness of the compounds of structural formulas I, II, III and IV in improving the etching properties of the coating and the further improvement resulting from the additional presence of the compound of structural formula V. Illustrative Example 2 A series of silver halide emulsions were prepared with increasing grain size. All emulsions had a composition of 98% silver chloride and 2% silver bromide. Emulsion grain size was controlled using well known techniques of varying temperature, addition rate, and amounts of silver and halide solutions. Each emulsion was split in two, one of which was coated without further addition. The other is compound 1 (0.25 g / mol silver) and compound 7 (0.07 g / mol silver)
Was added. All emulsions were coated and tested as described in Example 1.

The maximum etching capacity of the emulsion is shown in Table 2.

The results, shown in Table 2, demonstrate that the effectiveness of the inventive additives in improving the etchability of coatings depends on the grain size of the emulsion.

Example 3 A series of silver halide emulsions was prepared by varying the chlorobromide ratio and using the procedure as described in Example 1. All emulsions had grain sizes in the range 0.078-0.088μ.

The emulsion was coated as described in Example 2 with and without addition of compounds 1 and 7. The maximum etching capacity of these coatings is reported in Table 3.

The results, shown in Table 3, demonstrate that the effectiveness of the compounds of this invention in improving the etchability of coatings depends on the salt-bromide ratio of the emulsion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Paolo Beretta Savona, Italy, Italy Fuerania 17016, 3M Italy Riciers Societa Pel Atsioni Attention (72) Inventor Jionathan Peter Kitzchin UK SIE M 19 5 AESETX, Harlow, Pinnacles Minesota 3M Research Limited (56) Reference JP 55-22751 (JP, A) JP 59-55426 (JP, A) JP 60-178445 (JP, A)

Claims (10)

[Claims] 1. A silver halide light-sensitive material containing an imagewise exposed high chloride fine grain silver halide emulsion is developed in an alkaline developer to produce a halftone halftone image, and A halftone image photoengraving etching method of subjecting the developed silver image to dot etching with a silver halide oxidizing solution, wherein the silver halide photosensitive material is a thiazolium salt compound, a thiazole compound, and a pyrazole compound. A photolithographic dot-etching process as described above, characterized in that it comprises a compound selected from the group consisting of: in an amount such that a reduction in dot area occurs without significant reduction of small dots. 2. The silver halide light-sensitive material comprises a mercaptotetrazole compound in combination with a compound selected from the class of thiazolium salt compounds, thiazole compounds and pyrazole compounds. Photolithographic dot-etching method. 3. A thiazolium salt, a thiazole, and a pyrazole compound have the formula (In the formula, R ₁ represents hydrogen, a mercapto group, an aliphatic group, or an aromatic group, R ₂ represents an aliphatic group or an aromatic group, R ₃ represents a divalent group, R ₄ represents hydrogen, Represents a mercapto group, an aliphatic group, or an aromatic group; Q ₁ and Q ₂ represent an atom selected from the group consisting of nitrogen and carbon atoms necessary for completing a single or fused 5-membered ring; ₃ represents an atom necessary for forming a condensed ring, and X ⁻ represents an anion.) The photolithographic dot-etching method according to claim 1 or 2. 4. A black and white silver halide for line or halftone image contact copying, which comprises one or more hydrophilic colloid layers coated on a support, at least one of which is a silver halide emulsion layer. A photosensitive material, wherein the silver halide emulsion is a high chloride fine grain silver halide emulsion, and the silver halide photosensitive material is a compound selected from the group of thiazolium salt compounds, thiazole compounds, and pyrazole compounds, And a black-and-white silver halide light-sensitive material for line or halftone image contact copying as described above, containing in an amount such that dot etching causes a reduction in halftone dot area without significant reduction of small halftone dots. 5. The line of claim 4 wherein the photosensitive material comprises a mercaptotetrazole compound in combination with a compound selected from the class of thiazolium salt compounds, thiazole compounds and pyrazole compounds. Black and white silver halide photosensitive material for halftone image contact copying. 6. The silver chloride content of a silver halide emulsion, the grain size of silver halide grains, and a compound selected from the group of thiazolium salt compounds, thiazole compounds and pyrazole compounds or a combination thereof with a mercaptotetrazole compound. The amount is 10% halftone dot area ratio is 3
% Without reducing the concentration of 100% halftone dots to less than 2.0, and the halftone dot area ratio of 50% halftone dots to 10%.
A black-and-white silver halide light-sensitive material for line or halftone image contact copying selected according to claim 4 or 5 selected to provide an etching process which reduces by more than%. 7. A thiazolium salt, a thiazole, and a pyrazole compound have the formula (In the formula, R ₁ represents hydrogen, a mercapto group, an aliphatic group, or an aromatic group, R ₂ represents an aliphatic group or an aromatic group, R ₃ represents a divalent group, R ₄ represents hydrogen, Represents a mercapto group, an aliphatic group, or an aromatic group; Q ₁ and Q ₂ represent an atom selected from the group consisting of nitrogen and carbon atoms necessary for completing a single or fused 5-membered ring; ₃ represents an atom necessary for forming a condensed ring, and X ⁻ represents an anion). A black and white silver halide photosensitive material for line or halftone image contact copying according to claim 4 material. 8. A black-and-white silver halide photosensitive material for line or halftone image contact copying according to claim 4, wherein the silver halide grains have a size of less than 0.15 μm. 9. The black or white for line or halftone dot image contact copying according to claim 4, wherein the silver halide is silver chlorobromide or silver chloroiodobromide containing 60 mol% or more of silver chloride. Silver halide photosensitive material. 10. A silver halide light-sensitive material containing a compound selected from the group of thiazolium salt compounds, thiazole compounds and pyrazole compounds or a combination thereof with a mercaptotetrazole compound in an amount of 0.01 to 2 g per mol of silver. A black-and-white silver halide photosensitive material for line or halftone image contact copying according to claim 4 or 5 contained therein.