CA1110484A - Light-sensitive silver halide photographic material containing a tetrazolium compound - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Light-sensitive silver halide photographic materials to be treated with a hydroquinones-containing developing solution which material comprises a support and at least one hydrophilic colloidal layer coated thereon containing silver halide grains having an average grain size of 0.05 to 1.5 µ and a tetrazolium compound and a method of processing thereof.

Description

The present invention relates to a novel light-sen-sitive silver halide photographic material and the processing method therefor. Particularly, it relates to a novel lith type light sensitive silver halide photographic ma-terial for obtain-ing a photographic image with an especially high contrast, high sharpness and hish resolving power, and to the processing method therefor.
More particularly, it relates to a novel light-sensi-tive silver halide photographic material ~h-ch is applicable ad-vantageously to a ]ight sensi-tive silver halide photographic ma-terial with a high contrast suitable for formin~ a clot-- or line-ima~e on a lith (printing) li(~ht-sensltive silvel^ halicle material or (~ co~yin~ light-serlsitive materia:J, as ~re~ll as t:o the r~rocessin~
m~?~ od t~ or.
It has been known to Eorm a L~ho-tographic image with an extremely high contrast by using some Xind of a light-sensitive silver halide photographic mater:ial.
It has been }cno~n, for e~ample, to obtain a high con-trast image, e.g. a line- or dot:-image, by treating, with an al-lcalirle hydroquinones developing solution containing sulfite ionsin a very low concentration, a light-sen.sikiv~ material which c:om-prise~ a silver halicle emulsion containir-cJ silver chloricle in a high content (at least more than 50 mole %) and further containing silver iodide less than 5 mole %, the grains of which emulsion being minute (average grain size, ca. 0.3 ~),uniform in size and shape, and the grain size distribu-tion thereof being narrow. The above-mentioned kind o~ light-sensitive silver ha:Lide matcrial is known as the lith type light-sensitive material.
In printing business, there is usually required such a process as to convert a continuous gradation original image to a dot image, i.e. a process to convert the densities of the con-tinuous gradation to a predetermined numbered assembly oE dots respectively h~ving are2 of the same densities but proportional in size to the densities of the con~inuous gradation. In order to carry out -this, -the lith type light-sensitive material is sub-jected to development, af-ter photographing the original image through a cross- or contract-screen, to form the dot image on the light-sensitive material.
For this purpose there has been employed a light-sen-sitive silver halide photographic material containing a silver ha-lide emulsion, the yrains of which being minute and being uniform 1~ in size and shape. Even when this kind of a ligh-t-sensitive sil-ver halide photographic material is ernploy~d, the :intermediate density recJion (un(l~si.recl con~:inuous gradation parts) is repro-(luc~cl, be;ide the max:irnum cl~nsJt~ rec~1on alltl the minilllum one (fo~J),whcn th~ m~ter;;al is procec:secl with a stanclard b:L~ck and whitc-~ cle-veloping solution. The intermedia-te density region oE the so-cal-led flinge is undesirable for producing printing plates and makes the dot quality worse.
There has heretofore been employed the li-th type light-sensitive material also Eor l:he reproduction oE a line image. For ~ the sam~ reason, however, there have been obtained images having at h~,t the ~-valuc oE 5 - 6 o the characteric.tic curve, t~lich value is lower than 7 ~ 9 required Eor for~ing the desirable line image, if -the standard black and white developing solution is em-ployed. In order to avoid this, there has been employed, as men-tioned above, a specific developing solution called l'an infectious developing solution ". It is indispensable, however, to maintain the sulfite concentration in the in-Eectious dev~lop:ing solution as low as possible to obtain a high contrast image, but such the de-veloping solution ~s very poor in storability hecause of the low concentration of the sulEite so that this have caused a big trou-ble in printing business. ~very efEort has been macle, however, to improve the storability. Mevertheless~such efforts have not been so succe~sful. As a result, an ordinary developing solution for continuous gradation, such as Meto/hydroquinone or phenidone~hy~
droquinone developing solution which is excellent in the storabi-lity, is recommended for processing the lith light-sensitive ma-terials. However, there has been known no method capable of ob-taining a dot image with a good dot ~uality by using such the de-veloping solution.
It is, therefore, the primary object o the invention to provide a novel light-sensitive silver halide photographic material and the processing method thereof to obtain a high con-trast silver image.
It is arlother object of the invention to provide a l~th type ligh~-sens:itive silver halide mater:ial containing a te-~r~zolium compound suitable for obtaining a dot- or line-image.
It is still another object of the invention to provide a novel procesqing method of the above-mentioned lith type light-sensitive ~ilver halide material to obtain a high contrast black and silver image, especially a dot- or line-image~
The inventors have found, after extensive studies to attain the above-mentioned objects, that the objects can be at-tained by processing a lith type light-sensitive silver halide photographic material containing, in a hydrophilic colloidal layer, silver halide grains having a narrow grain size distribution and a tetrazolium compound, after exposure, with an ordinary develop-ing solution containing a hydroquinones developing agent as a main developing agent.
The present lnvention is concerned wlth a light sensitive silver halide photographic material which consists essentially of a support, at least one hydrophilic colloidal layer coated thereon containing silver halide grains having an average grain size of from 0.05 to 1.5 ~ and at least 75% of which grains being within a range of fxom 0.6 to 1.4 times said average grain size, and a tetrazo:Lium compound selected from the group consisting of a compound of formulae (I), (II) or (III):

N N (X )n-l ( ) ~ I ~

R~ - N ~ - N--D- N---N~ ~ R5 ~3 C C 2(X )n-1~II) 9 - N N - Rg E - ~ (III) 1~ 3~ R4, R5, R8, Rg, Rlo and Rll each represents an aryl group or a heterocyclic group; R2, R6 and R7 each represents an aryl group, a heterocyclic group, an alkyl group, hydroxyl, carboxyl or the salt thereof, an amino group, me.rcap-to, nitro or hydrogen; D represents a dlvalent aromatic group;

- 3a -~' E represents an alkylene group, an arylene group or an aralkylene group; X is an anion; said heterocyclic group being selected from the group consisting of a thiadiazolyl group, a benzothiadiazolyl group, an oxazolyl group, a pyrimidinyl group, a pyridyl group and a 2,5-dimethyl-thiazolyl group' and n is 1 or 2, provided that the compound forms an intramolecular salt when n is 1.
In accordance with the invention, there can be formed a superior line~ or dot-image, without employing the infectious development, by processing a light-sensitive silver halide pho-tographic material having, coated on a support, at least one hydrophilic colloidal layer whlch comprises light-sensitive silver , ~ 5~48~

halide grains having an average grain size of 0.05 - 1.5 ~ and at least 75 % of the tol~al grains being within the range of 0.6 -1.4 times larger than the (average grain .size) and a tetrazolium compound, after the image exposure, with a hydroquinones-contain-ing developing solution.
According to a preferred embodiment of the invention there is obtained a hiyh contrast silver imacJe with a superior reproducibility of the line image by processiny a light-sensiti-ve silver halide photographic material containing silver halide grains having the ahove-mentioned yrain size and rhe distribution thereof (hereinafter referred to as the silver hali.de of the in-vention ) and a diffusible tetrazo.lium corn~ound c~ft:er the lrna~e ~posur~, w:i.th a hydroquirlone~3-contain.i.n~ develor)irlcJ solut.iorl.
Accordi.ny to another pr~ferred elrlbodiment of the in-vention, there is obtained a dot image (half tone image) wi-th a superior dot quality by developing a light-sensitive silver halide photographic material containiny the silver halide of the inven-tion and a non-diffusible tetrazolium compouncl, aEter thc image exposure throu~h a contact screen, with the Metol/hydroquinone dev~loping solution (herei.nafter referred to as the MQ developing solution) ox wi.th ~h~ phenidone h~droquinone developin~ solut~,on (here~inafter referred to as the PQ developln~ solut.ion) whlch are famous and popular for the black and white developi.ng solution.
I-t can not be expected from heretofore known techni-ques that the high contrast line- or ~ot-image could be obtained without employing the infectious developing solu-tion.
As explained above, the tet.razolium compotlnds inclu-de non-diffusible and diffusible ones. The term "non-diffusible tetrazolium compound" means a compound which does not dissolve from the li~ht-sensitive material to the developing solution dur-ing the developmen-t. In o-ther words, -the compoun~ does not dis-solve in a concentratic)n o~ several%, preferably not more than

2 %, when a gelatin layer containing the compound is dipped for 10 minutes in an aqueous solution at 2a - 40C having the same ion strength and pH-value as those o the developing solution.
The representa-tive tetra~.olium compounds employed in the invention include the follo~ing compounds represen-ted by the general formulae :

f R
¦ Rl-N~ - I 3 n-l ;
~ ~ ( }

R4~N~Y N _ _D __ N~__.-N-R .

N MM ~ M 2~X ~ 1 ~0 R ~-~ N-R~ l?~Lo-N~ .. M 11. (III) N ~ N N
\ ,~ "~ 2(~

- E - - _ f J

1 3 ~ 5 8 9 10 and Rll each represent a group selected from an aryl group such as phenyl group (e.g. phenyl, tol.yl, hydroxylphenyl, car~oxyphenyl, aminophenyl or mercaptophenyl, carboxyethyL, nitro~ihenyl, etho-x~phenyl, iodophenyl, meth.ox~phenyl, cyanophenyl, acetamidophenyl, q~

etc . ) and a naphthyl group (e.g. c~-naphthyl, ~-naph-thyl, hydroxy-hapht'nyl, carboxynaphthyl or aminoaph-thyl, e-tc . ), and a heterocyclic gro~p ( e . g . thiadiazolyl, benzothiadiazolyl, oxazolyl pyrimidinyl, py-ridyl, 2, 5-dimethyl-thiazolyl, etc. ) . The group can advantageously contain an elec tron sharing group capable of :~o~mi.ng a rnetal che-late or a complex sucn as primary, secondary, tertiary ami.do oxime, thio ether, keto, thioketo, hyclroxyl, mercapto, caxboxyl, sulfo, phospho alkoxyl and : R2 ~ R6 and R7 each represent a group selected from an aryl group such as a phenyl c~roup and a naphty:L group, a he-terocyclic group, an alXyl group (e.g, methyl, e1.hy:l, propyl, ~u-tyl, mercaptomethyl or mercaptoethyl and a carboxyalkyl group such as a methoxycarbonyl or ethoxycarbonyl ), hydroxy]., car~oxy or the ,sa~ thereol~, an alni.no CJrOU~ ?.('J. <lmlllO, C!ttlYI~rll;rlO Or an:l.Li.nC)), morc-ll?t.o, nit:ro ~ln~ ycl:r~oclc-r~ ) rc~prosc!nt.~; a cl.iva:k:nk aro~ t.:i.e (~.rou~-yxoup; 13 :repr~?sc?nts a (J:rOUP s~:Lec~ecl :ELOm an a:Llcy:].c:~ rOUP, arl arylene group and an aralkylene group: X is an anion; and I1 iS 1 or 2, provided that the compound forms an intramolecular salt when n ls 1.
In the above forrnula, the divalen-t aromatic group :Eor E is preferably an arylene group (e.g. phenylene, alko.xy-substi-tutecl phenylen~? such as methoxy-subst:itu~ed phenylene, naphthylene, ~liph~rlyl.t~ne~, ~tc . ) or a cl:ivaLerlt aronati.e hel:eroc yc.li.c yroup.
The followincJ are typiea:L exarllples oE the ca tionic moieties of the te trazoliurn compouncls thereof .
( 1 ) 2- ~ Benzo thiazol-2 -yl ) -3-phenyl-5-dodecyl-2H-tetrazolium ( 2 ) 2, 3-Diphenyl-5- ~ 4-t-octyloxyphenyl ) -2 ~-te-trazolium ( 3 ) 2, 3, 5-Triphenyl-2H-tetrazolium ( 4 ) 2, 3 5 -Tr.i (p-earboxyethylphenyl ) - 2H- te-trazoliurn ( 5 ) 2- ~ Benzothiazol-2-yl ) -3-phenyl-5- ( o-chlorophenyl ) -2H-tetrazolium (6 ) 2, 3-Diphenyl-2H-tetrazolium ( 7 ) 2, 3-Diphenyl-5-rnethyl-21I- te trazoli.um ?l~

(8) 3-(p-Hydroxyphenyl)-5-methyl-2-pnenyl-2H-tetrazoliuTn (9) 2 3-Dir~nerlyl-5-ethyl-2H-tetrazolium (~.0) 2 3-Diphenyl-5-n-hexyl-2H-tetrazolium (11) 5-Cyano-2 3-diphenyl-2H-tetxazolium (12) 2-(BenzothiaY.ol-2-yl)-S-phenyl-3-(4-tolyl)-2H- tetrazolium (13) 2-(Benzothiazol-2-yl)-5-(4-chlorophenyl~-3-(4-nitrophenyl)-2H-te-trazolium (14) 5-Ethoxycarbonyl-2 3 di 3-nitrophenyl)-2H-tetrazolium (15) 5-~cetyl-2 3-di(p-ethoxyphenyl)-2H-tetra;olium (16) 2 5-Diphenyl-3-(p-tolyl)-21-I-tetrazolium (].7) 2 5-Diphenyl-3-(p-iodophenyl)-2H-te-trazolium (18) 2 3-Diphenyl-5-(p-d:i.pheny1.)-21~ tetra7Oiium (l.3) 5~ B:~o.~l~.)p~ r~y~ r?~lC~llyl~- s- (?. 1 G-t; r:L~ :r~ rlyl)-;?.I-I-tr.l.~lY.o:lium (20) 3-(p-hydroxyp~l?nyl)-5 (p-n:itrop~lerly:l.)-2--r)llcny:L-2[1~t(?t:r zolium (21) 5-(3 4-Dimethoxyphenyl)-3-(2-ethoxyphenyl)-2-(4-methoxy-phenyl)-2H-tetrazol;.uTn (22) 5-(4-Cyanophenyl)-2 3-diphenyl-2H-tetrclzolium (23) 3-(p-Acetamidophenyl)-2 5-diphenyl-2H-tetrazolium (2~) 5~ cetyl-2 3--dipheny].-2H-tetrazoliuTn (25) 5-(Fur-2-yl)-2 3-diph~lly:L-2I-I-tetraY~o.l.:ium (26) 5-(Thien-2-yl)-2 3-diph~nyl-2~I-te~razol:i.~lm (27) 2 3-Diphenyl-5-(pyrid~-yl)-211-tetrazolium (28) 2 3-Diphenyl-5-(quinol-2-yl)-2H-tetrazolium (29) 2 3-Diph2nyl-5-(benzoxazol-2-yl)-2H-te-trazolium (30~ 2 4-Diphenyl-5-nitro-2H-tetrazolium (31) 2 2 3 3 -Tetraphenyl-5 5 -1 4-butylene-di--(2H--tetrazolium) (32) 2 2 3 3 -Tetraphenyl-5 5 -p-phenylene-di-~2H-tetrazolium) (33) 2-(4 5-Dimethylthiazol-2-yl)-3 5-diphenyl-2H--te-trazolium (34) 3 5-Diphenyl-2-(trizin-2-yl)-2H--te-trazolium (35) 2-(Benzothiazol-2-yl)-3-(4-methoicyphenyl)-5-phenyl-21I--tetrazolium . ~ --7--tetrazolium (36) 2,5-diphenyl-3-~-naphtyl-2H-tetrazolium (37~ 3,3'-~3,3'-dimethox~-4/4'-diphentylene3-2,2',5,5 tetraph~nyl-di~(2H-tetrazolium) As the anionic moieties, are mentioned, e.g. a halogen ion, a thivsulfate anion, a sulfate anion, a thiocyanate anion, an alkylsulfate anion, a nitrate anion, an acetate anion, a lower al-kylbenzene sulfonate anion for the diffusible tetra~olium compound and a 'r,igher alkylbenzenesuLfon~te anlon such as p-dodecyl.benzene-lO ~ sùlEonate anion, a hi.~her alkylsulfate anion such as laurysulfate anion, a dialkyisulfosuccinate anion .5uch a'; d-2.-eth~lhexylsulfosuci--nat~ n:ion, ~ ~oly~t.hc~r ~lcohol .~.3U.~.~clte ~.ln:iOn .5uch as (~C?tyl~.~oly-e~lonoxysul~ate an.i.on, ~ hi~h~r .l.atty acic~ an:ion SllCh a~s~ st~ar.ic acicl an.ion, and a po:Lymer haviny acid radicals such as polyacr~-late anion for the non-diffusible tetrazolium compound.
Most typical examples of the compouds of the inven-tion are as follo~s :
(l) 2,3,5-Triphenyl-2H-tetrazollum ch].oride (2) 2,3,5-Tri(p-carboxyethylphenyl)-2E'~-tetrazoliurn iodide

(3) 2-(Benzothi.a~.ol-2--yl)-3-L)henyl-5(o-chloroptl~nyl)-2 tetrazol.ium hro~i-le

(4) 2,3-Diphenyl- 2II-t~trazoliu.~ thiasulEate

(5) 2,3-Diphenyl-5-methyl-2H-te-trazolium chloride

(6) 3-(p-Hydroxyphenyl~-5-methyl-2-phenyl-2M-tetrazolium sul-fate

(7) 2,3-Dlphenyl-5-ethyl-2H-tetrazolium chloride (8~ 2,3-Diphenyl-5-n-hexyl-2H-tetrazolium chloride (9) 5-Cyano-2,3~diphenyl-2H-tetrazolium thiocyanate (lO) 2-(Benzothiazol-2-yl)-5-phenyl-3-(4-tolyl)-2H-tetrazolium chloride (11) 2-(Benzvthiazol-2-yl)-5-(4-chlorophenyl~-3~ -nitrophenyl)~
2M--tetrazolium chloride (12) 5-Ethoxycarbonyl-2,3-di(3-nitrophenyl)-2H-tetrazolium bromide (13) S-Acetyl-2,3-di(p-ethoxyphenyl)-2H-tetrazolium chlori~e (14) 2,5-~iphenyl-3-(p-tolyl)-2H-tetraxolium methylsulfa-te (15) 2,5-Diphenyl-3-~p-iodophenyl)-2H-tetrazolium chloride (16) 2,3-Diphenyl-5-(p-diphenyl)-2H-tetrazolium chloride (17) 5-(p-Bromophenyl)-2-phenyl-3-(2,4,6 trichlorophenyl)-2H-tetrazolium chloride (18~ 3-(p-Hydroxyphenyl)-5-me-thyl-2-phenyl-2H-tetrazol.ium chloride (19) 5-(3,4-Dimethoxyphenyl,~-3-t2-ethoxyphenyl)-2-(4-me-thoxy-phenyl)-2H-tetrazolium chloride (20) 5-(4-Cyanophenyl)-2,3-dlphenyl-2lI-t:etrazo.l..ium chloride ~2.l) 3-(p-~t~mi.dophenyl)-~,S-d.~ph~n~1-2~l-tetxcl7.ol:ilm~
chloride (22) 5-Acetyl-2,3-diphenyl-2H-tetrazolium chloride (23) 5-(Fur-2-yl)-2,3-diphenyl-2H-tetrazolium chloride (24) 5-~l'hien-2-yl)-2,3-diphenyl-2EI-te-trazolium chloride (25) 2,3-Diphenyl-5-(pyrid-4-yl)-2H-tetrazolium nitr~te (26) 2,3-Diphenyl-5-(quinol-2-yl)-2H-tetrazolium chloride ~27) 2,3-Diphenyl-5-(benzoxazol-2-yl)-2H--tetrazolium chloride ~?.8) ~,3-Diphenyl-S-nitro-2E1-t~trazolium methylsul.fate (29) 2,2',3,3'-Tetraphenyl-5,5'-1,~-butylene-di(2~I-tetra-zolium chloride) (30) 2,2~,3,3',-Tetraphenyl-5,5'-p phenylene-di-(2H-tetra-zolium chloride) (31) 2-(4,5-Dimethylthiazol-2-yl~-3,5-diphenyl-2~I-tetrazolium chloride ~32) 3,5-Diphenyl-2-(triazin-2-yl)-2H-tetrazoliun sulfate (33) 2-(Benzithiazol 2-yl)-3-(4-methoxyphenyl)-5-phenyl-2~I-tetrazolium chloride (34) 2,5-diphenyl-3-a-naphtyl -2H-tetrazolium chloride (35~ 3,3 7 - ( 3,3'-dimethoxy 4,4'-diphenylene)~2~2 t ~ 5,5~_ tetraphenyl-di~(2E~-tetrazolium chloride) ~36) 5-(3-~ethoxyphenyl)-3-(3-tri.~luoromethylphenyl~-2-phenyl-2H tetrazolium acetate ~21 Non diffusible tetrazolium compound (37) 2-(Benzothiazol-2-yl)-3-phenyl-5-dodecyl-2H-tetrazoli~n bromi.de (38) 2,3-Diphenyl-5-(4-t-octyloxyphenyl)-2H-tetrazolium chlo-ri.de (39) 2,3,5-Triphenyl-2H--tetrazolium-diethylhexylsuccinate sulfonate (~0) ?.,3,5-Tri(p-carboxyethylphenyl.)-2II-t.etr.l~,olillm p-dode-~:ylbenztene-c~ulforlate.
(~1) 2-(13enzoth:i~zo:l-2-y:L)-3-1,~henyl-5--(o~chl.orc)r.)heny~ 211~
t~tra~,ol:i.utn cIi~?thylhexylsuccin;lte sulfonate t42) 2,3-Diphenyl-2H-tetrazoliurn p-octylbenzenesulfonate (43) 2,3-Diphenyl-5-methyl-2M--te-trazolium laurysulate (4~) 3~(p-fIydroxyphenyl)-5-methyl-2-phenyl-2II--tetrazolium isopropylnaphtalenesulEonate (45) 2,3-Diphenyl-5-ethyl-2lI-tetr.lzol.ium di-ethy.l.he~y.l.sul.Eo~
succir~te ~6) 2,3-Diph~nyl-'j~n-hcxyl-2I~-tc~trazolium cety:l.polyetheno~y-sul.Eate (47) 5-~yano-2,3-diphenyl-2H tetrazolium polyacrylate (48) 2-(Benzothiazol-2-yl)-5-phenyl-3-(4-tolyl)-2H-tetrazolium ~-diethylhexylsuccinate sulfonate (49) 2-(Benzothiazol~2-yl)-5~(4-chlorophenyl)~3-(4-nitrophenyl)-2H-tetrazolium diethylhexylsuccinate sulEona-te : (50) 5-Ethoxycarbonyl-2,3-dit3-nitrophenyl)-2EI-tetrazolium~
diethylhexylsuccinate sulfonate (51) 5-Acetyl-2,3-di(p-ethosyphenyl)-2H-tetraxolium-diethyl-hexyls~ccinate sulfonate t~

(52) 2,5-~iphenyl-3-(p-tolyl)-2H-tetrazolium-p-octylbenze-nesul~onate (53) 2,5-Diphenyl-3-(p-iodophenyl)-2H-tetrazolium-p~ctylben~e-nesulfonate (54) 2,3-Diphenyl-5-(p-diphenyl)-2H-tetrazolium p-octylben-zenesul-fonate (55) 5-(p-Bromophenyl)-2-phenyl-3 (2,4,6-trichlorophenyl)-2H-te-trazolium isopropylnaphtalenesulfonate (56) 3-(p-Hydoxyphenyl)-5-~p-nitrophenyl)-2-pheny1.-2II--tetrazolium diethylhexylsuccinate sulfona-te (57) 5-(3,4--Dimethoxyphenyl)-3-(2-ethoxyphenyl)-2--(4-methoxy-phenyl)-2I-I-tetraæolium di.ethylhexylsllccinate sul~onate ~58) 5-(4 Cy~noph~nyl)-2,3-d:iph~nyl-?.~ tetra~.olium diethy1-hexylsuccinate sulEonate (S9) 3-(p-~ceta~nidophenyl)-2,5-di.phe~nyl-2II-tetrazolium lauryl-sulfate (60) 5-Acetyl-2,3-diphenyl-2H-tetrazolium diethylhexylsucci-nate sulfonate (61) 5(Fur-2-yl)-Z,3-diphenyl-2~I-tetrazolium diethylhex~
succinate su.l.fona-te (62) 5-('.~ien-2-yl)-2,3-diphenyl.~2II-t~tra:~olium diethylhexyl-succinate sulfonate (63) 2,3-Diphenyl 5-(pyrid-~-yl)-2H-tet.razolium diethylhexyl-succinate sul:Eonate (64) 2,3-Diphenyl-5-(quinol-2-yl)-2H-tetrazolium diethyl-hexylsuccinate sulfonate (65 ? . 2,3-Diphenyl-5-(benzoxazol-2-yl)-2H-tetrazolium diethyl-hexylsuccinate sulfonate (66) 2,4-Diphenyl-5-ni-tro-2H-tetrazolium polyacrylate (67) 2,2',3,3'-Tetraphenyl-5,5' 1,4-butylene-d~ H tetra~-o-lium) laurylsu1.fa-te (68) 2,2'3,3'^-~etraphenyl-5,5'-p-pheI~ylene-dl-(2H-tetrazolium) cetylpolyethenoY~ysulfate (69) 2 (4,5-Dimethyl-thiazol-2-yl)-3,5-diphellyl-2H-tetrazoliurn polyacrylake (70) 3,5-Diphenyl-2-(triazin-2-yl)2H-tetrazoliunl stearate (71) 2-(Benzothiazol-2-yl)-3-(4-rnekhoxyphenyl~-5-pllenyl-2H-tetrazoliurn di-ethylhexylsulfos~ccinate (72) 2,5-Diphen~rl-3-a-napthyl-2H-tetrazolium clodec~rlsulfate (73) 3,3'-(3,3'-Dimethoxy-4,4'-diphenylene)-2,2',5,5'- tetra~
phenyl-di-(2H-tetrazolium polyacrylate) (7~) 5-(3-Methyloxyphenyl)-3-(3-trifluoromethylphenyl)-2-phe-nyl-te-trazolium isopropylnaphtalenesulfonate The non-d~ f~lsihl.e or diE~usible tetrazolium compounds accord.inc3 t:o the inverltiosl are t:~lUS synt~-ler~ .ed hy an oF>ti.onal se-l.~ction oE the allionic ar)d cat:i.onic moiety. r~c~ n-di:f~Eu5:ibl~
com~ounds, e.g. 2,3,5-triphenyl-~H-tetrazo:Lium dioctyl--3uccinate~
sulfonate, nay be dispersed into a gelatin solution by mixing the respective soluble tetrazolium salt and the ~elatin to disperse them in the gelatin solution and then by that op'cimum anion is admixed thereinto therehy to ob-tain the gelatin solu-tion dispersed wi.th the non-diffusible tetrazoliuln compound as specifical:Lyrnen-t.i.on~d in E~ample~s set ~orth la~e.
~ lte:rllatively, crystals of the non-d:i~fus;.ble te-trazolium compound purely sunthesized may be dissolved in a sui- ..
table solvent 5uch as dimethylsul~oxide and then dispersed in the gelatin solution. ~hen the dispersion is not sufficiently homo-geneous,good results rnay be obtained by exposing the emulsion di-persion to an ultrasonicwave or by use of a suitable homogenizer such as Man-ton-~aulin homogenizer.
As mentioned above, the tetrazoliurn compounds of this invention may be used both in diffusible and non-cliffusible forms, when the silver halide of this invenkion is employed. However, the hicJher contrca3t image may be obtained by emplc)ying the non-~1~--diffusible tetrazolium compounds. Accordingly, it is advantageousto employ the non-diffu~ e tetrazoliurn cornpound wh~n an especial-ly su~erlor aot quality i~ required~
On the other hand, the use of too much high contrastlight-sensitive material sometimes brings about not sufficient reproduction of the line image, particularly those of fine letters and lines. In this case an image with more superior quality may be obtained by the use of the diffusible tetrazolium compounds.
According to a preferred embodiment of the invention, the tetrazoliurn compound of the invention is incorporated into a silver halide emulsion layer~
~ ccording to another preferred ern~ocliment of the in-v(~3nt10n, ~he compound i~ incorporated in a layer adjacen~ (or a la~er adjace~nt to said adjacent layer) to the layer containir the silver halide emulsion.
The above-mentioned compounds of the invention may preferably be employed in an amount of 0.0001 - 10 mole, more pre-ferably 0.0001 1 mole, per mole of -the silver halide contained in the light-sensitive silver halide photographic material of -the invention. As the silver halide employed for the light-sensitive silver halide photographic rnat:erial o~ the invention includes any silver halide used for the conventiorlal silver halide photographic materials, e.g. silver bromide, silver chlorobromide, silver io-dobromide, silver chloroiobromide or ~ilver chloride and the liXe~
The average grain size of the silver halide in the invention is 0.05 - 1.5 ~, preferably 0~1 - 0.8 ~, and at least 75 % of the total grains are wi-thin a range of 0.6 - 1.4, prefe-rably 0.7 - 1.3 times larger than the average grain siæe. Fur-thermore, the silver halide comprises silver chlorobrornide or chloroiodobromide containing at least 50 mole ~/O silver chloride.
The silver halide of the invention having the above-melltioned average grain size and the distribution thereoE may be prepared by any known method described, e.g. in U.S~ Patents 2,592,250 3,276,877, 3,317, 3~ , 2,222,264, 3,320,069 and 3,206,313 and in Jouxnal of Photographic Science 12(5), 242-251 (1964).
Silver halides prepared by other me-thods may also be employcd in mixture.
Accoxding to the rnost preferred concrete embodiment of the invention, the silver halide of the inven-tion is silver chloroioclobromide or chlorohromide having an average grain size of 0.1 - 0.5 u and at least 80 % of the -total gralns be~ing within a xange of 0.7 - 1,3 times larger than the averaye graln size.
The silver halide emulsion of -the inven-tion may be s~n3iti7~e~ with various ]cind- of chernical sensiti7~ers~ ~s the ~s~n;;itl~er, .Ir~? ment-ioned, ~or ex~ple, acl;ivaked cJela~in, sulfur .(3~n'~ r~ `.CJ. '~O~li.lll'.l ~:h.~.03u~1..ea~ ry~ .ioc-l:r~atTli.~lc`, t.~lio~
or aryl isocyanate, etc.), selenium serlsi-tizers (~.g. ~,N-dime-thylserenourea or selenourea, etc.), reducing sensitizers (e.g.
triethylenetetramine or stannic chloride, etc.) and various no-ble metal sensitizers represented by potassium chloroaurite, po-tassium aurioth:iocyanate, potassium chloroaurate, 2-auro-sulfo-benæothiazole methylchloride, arnmonium chloropalladate, potassium chloroplatinate and so~iurn chloropalladite. The sen3itizerC, may be elnploye(l alone, or mixed together. Ammor,iu~ hiocy(:lnate may be auxiliarily ernployed ~hen a gold sensitizer is employed.
Furthermore, the silver halide emulsion used in the invention may be sensitized optically with one or more sensitizing dyes to give a li~ht sensitivity within the desired ligh-t-sensi-tive wave length.
Various kinds of sensitizing dyes may b~ employed for the purpose. As the optical sensitizers employed advantageously in -the invention are mentioned, e.g. a cyanine, merocyanine, tri-or tetranuclei merocyanine, tri~ or tetranuclei cyanine, hemicyanine, o~onole, hemioxonole and the li~

-~ :L-~-ke.
The optical sen.sitizers preferably contain within the chemical structure thereof a nitrogen-containing heterocyclic nucleus,e.g. a basic group such as thiazoline or thiazole, or rho-danine, thiohydantoin, oxazolidine-dione, barbituric acid, thio-barbituric acid or pyrazolone. The nucleus may be subsituted with an alkyl, hydroxyalkyl, halogen,phenyl,cyano or alkoxy group or may be fused with a hydrocarbon or heterocyclic ring.
The silver halide emulsion of the invention may preferably be stabilized with 5,6-trimethylene-7-hydroxy-s-tria-zole (1,5-a) pyrimidine, S,6-tetramethylene-7-hydroxy-s--triazolo (1,5~a)pyrimidine, 5-methyl-7-hydroxy-s--triazolo-(1,5-a)pyrimidi-ne, 7-hydroxy-s-triclYolo~1,5-a)pyrinlidine, 5-methyl-6-brolllo-7~
hydrcxy-s-tric-lzolo~1,5-a) pyrimid:ine, cste~rs or salts of c3alllc acid (e.g. isoamyl g~llate, dodecyl gallate, ~)ropyl gallate or sodium gallate), mercaptans ~e.g. l-phenyl-5-mercaptotetrazole or 2-mercaptobenzothiazole), benzotriazoles (e.g. 5-bromobenzotriazole or 4-methylben~otriazole ) and benzimidazoles (e.g. 6-nitrobenzi-midazole) Such stabili~ers are clescribed in, e.g. U.S. Patents ~4,6U7, 2,716,062, 3,512,982, 3,342,596, 3,726,686 and 3,717, 46~, British Patent 1,363,921. E'urthermore, the silver halide emulsion o~ -the inven-tion may contain a latent image stabilizers such as a sulfur-containing amino acid, or a gradation-adjusting agent such as a cadmium or rhodium salt, described in, e.g. Bri-tish Patent 1,343,904 and U.S. Patent 3,821,295.
It has been known, e.g. British Patent 775,197 and U.S. Patent 3,488,709, to employ a rhodium or cadmiun salt to in-crease the contrast of silver halide emulsion. However, problems still remain when the rhodium salt is employed. For example, the use of rhodium salt tends to cause an unevenness of -the product due to the minute amount of addition and the narrow allowable ran-ge thereof o~ -the salt, and thus makes it difficult to produce stable photoyraphic materials. In case of the ~admiun, salt, it has to be added as little as possible from an ecological view-point, for it is washed out by film-processing and comes finally into the environment. The cadmium sa]ts are known to prevent the metabolism and -to be harm~ul to living tissues. Cadmium may be detected not only in air but also in the body o sea animals. ~s a result of interest in public health and the maintenance of nor-mal ecological balance in view of the to~icity of rare metals, including cad~ium mentionecl above, the inventors have reached the invention relatiny to a no~Jel method to obtain a light-sensitive material with sufficiently high contr~c;t, even in no use of such hclrm~ul rnctal,. ~n~3n the above-m~ntioned silver h~licl~ and te tra;~oLium corrlpouncl o~ the invention ~re incor~orat:(?cl into the hydrophillc colloidal layer.
The hydrophilic colloid advantageously employed in the invention i.5 gelatin. ~s other hydrophilic colloids than ge-latin are rnentioned, e.g. colloidal albumin, acJar, gum arabic, arginic acid, hydrolyzed ce:LLulose ace~-ate, acxylamide, imida-ted polyamide, polyvinyl alcohol, hydrolized polyvinyl aceta-te, water-501uhle pol~m~r clescrib~d in, e.g. Briti.sll Pa~ent 5%3,~)61, U.S.
Patents 3,8~7,620, 3,655,389 an~ 3,3~:L,332., ~lal-in deriva~ives such as phenylcarbamyl-acylated- orphthalate~-g~latin described in, e.g. U.S. Patents 2,614,928 and 2,525,753, or graft-polyme-rized monomers on gelatin having the ethylene group and being capable of polymerization, such as acrylic acid and the ester thereof, styrene, a methacrylic acid and the ester -thereof, des-cribed in e.g. U.S Patents 2,548,520 and 2,831,767.Such hydrophi-~c colloids mayalso be applied to a iayer containing no siLver ~lide, e.g. an antihalation layer, a protective layer or an in-t~-rmediate layer.
The light-sensitive silver halide material of the invention may be prepared ~y coating the above-m~ntioned layer con-taining the silver halide and the tetrazolium compound of the invention on a suitable photographic base. I~S the representative supports employed in -the invention are mentioned, e.g. a baryta paper, a polyethylene-coa-ted paper, a synthetic polypropylene paper, a glass plate, a ccllulose acetate or cellulose nitrate filrn, a polyester film such as a polyethylene terepht'nalate film, a polyamide ~ilm, a polypropylene film, a polycarbonate Lilm, a polystyrene film and the like. The suppor-ts are op-tionally selected depending on the purpose ~or which the ligh-t-sensitive photogra-phic material is used.
As mentioned above, -the light-sensi-tive silver hali-de photographic material oE thc inventiorl compr:.;.ses at least one hydrophili~ collo.idal layer, coated on the supr.)or~, coll~aining a s:ilver h~ L~Ie of t~li.,s invent.iorl and the tetra201:iurrl cornr~ound oE
the invention.
I~ is preferable in the light-sensitive material of the invention that a protective layer having a suitable thickness is coated. The protective layer is aclvantageously a gelatin layer the thickness, of which is preferably 0.1 - lO,u, more preferably ?.0 0.~ - 2Ø~.
'~'hc~ hitherto known lith typo l.ight-sensit.iv(? si:Lver halide photographic materials USJUa11Y have a protective lay~r.
In this invention, however, the protective layer plays an impor-tant role different ~om known cn~s.
The protective layer is, in general, coated for the purpose to protect the silver halide emulsion layer from an inci-dental mechanical damage during production processes, e.g. cutting, winding or wrapping process, or during photographing and/or pro-cess;.ng caused by con-tact of the li.ght-sensitive rnaterial wit:h other subs-tance.
It has turne~1 out that the protec-tive layer of the in~ention not only protects the above-rnentioned silver halide -:L7-~ L~ 4 emulsion but also plays an important ro~e fo~ processing stability.
That is, while the lith type light-sensitive material has to be able to form a very high con-trast line-and dot-image, if a com-pound oxidizable of a hydroquinone develc,ping agent is added in the light-sensitive ~ilver halide photgraphic material -to obtain the above-mentioned high contrast silver image, the above-mentioned -oxidizing agent gives a large influence on the development during the progress thereof and consequently, the quality of the line-or dot-image obtained is largely influenced by the difference of e.g. a developing time, a temperature and an amount of -the expo sur~
It is not necessari:ly elucidated in the process of ~he invention why the presence O;e the protective layer may act ~f~c~tiv~ly on the ~abilLty o~ the irnage quality and o th~ de-veloping process. Presumably, the protective layer may have a function to control ade~uately the infiltration rate of the hy-dro~uinone/Metol or phenidone from the processing solution into the light-sensitive ma-terial, or the difusion rate of -the tetra-zolium compound within -the light-sensitive material or therefrom to the processing solution.
This eE~ect is remarlcable when the te~trazolium com-pound of ~he invention is employed. This ~E~ct is not so remar-kable when other oxidizing agent than the tetrazolium compound,described in, e.g. German Patent No. 2,634,666, published on February 7,1977, are employed.

Various kinds of photographic additives rnay optional-ly be added to -the above-mentioned hydrophilic colloid of the in-vention, as far as -they do not impair the effect of the invention.

As the additive~, are mentioned, e.g. a gelatin plasticizer, a hardening agent, a sur~ace active agent, an imaye stabilizer, an ultraviolet ab~orber, an antistaining ayent, a pH adjuster, an antioxidant, an antistatic agent, a viscosity-increclsing agc-nt, 4~il4 a granularity improving agent, a dye, a mordant, a brightening agent, a development regulatorl a matting agent, and the like.
~ mong the additives mentioned above, -the following may particularly and preferably be employed: viscosity-increas-ing agents and plas-ticizers, described in U S. Patents 2,960,404, 3,767,410, 3,659,956 and 3,692 ,753, e.g. a styrene/sodium maleate copolymer and dextran sulfate, etc,hardning agents of aldehyde, epoxy, ethyleneimi.ne, active halogen, vinylsulfone, iso-cyanate, sulfinic acid ester, carbodiimide,a mucochlori.c acid, ~- or acyloy].s, etc,, i~aye stabilizers, e~g. 6,6'-butyli.clene-bis (2-t-butyl-4-~ethylphenol) and ~,4'-methy:lene-'b:i.s(~.,6-cl:i-t-butylpne-no:L), o~.c,; ~lltav.iolet ab;oxb~rs, clescrlbecl in, e .CJ. U . S . Patent 3,%53,92~ ,r;it:i.,h P~terlt. :l,30.9,3q9, U.S. Pa~ont.~ 3,53;,'79~ an(~
3,707,375 and Br.itish Pat~nt :l,287,770, p~rticularly 2-(2-~ydroxy-5.~-but.ylphenyl)benzotriazole,2-(2-hydroxy-3,5-di-t-butylphenyl) benzotriazole, 2-(hydroxy-3-t-butyl-5-butylphenyl)-5-chloroben-~otriazole and 2-(hydro~y-3,5-di-t-butylphenyl)-5-chlorobenzotria-zole, surface active agents for coating aids, emulsifiers, inEil-tration-irnproving agents for a processing solution, def'oamcrs, or agents ~or controlling var:ious physical properties oE the light-e:en~itive tnat~rial, descri'~ed :in, e~.y. U.S. Patellts 3,026,202, and 3,514,293, British Patents 548,532 and 1,216,38g, U.S. Patent 3,726,683, including anionic, cationic, no~.ionic and amphoteric compounds; mordants described in, e.g. U.S. Patents 2,113,381 and 2,548,564; antistaining agents described in, e.g. U.S. Patents 2,360,210, 2,728,659, 2,732,300 and 3,700, 453, particularly 2-methyl-5-hexadecyl-hydroquinone, 2-methyl-5-sec-octadecylhydro-quinone and 2,5-di-t-octylhydroquinone, etc;; antistatic agents described in, e~g. U.S. Patents 2,882,157, 2,972,S35, and 3,573,093 and British Patent 1,378,584 and U.S. Paten-ts 3,54l3,369, 3,704,128 and 3,663,230, matting agents described i.n, e.g. U.S.. Patents : ' 2,992,101 and 2.956,884, Br.itish Paten-ts 1,221,980, and 1,307,373, . ~ ~
~3 -19-particularly silica gel 'naving a grain size of 0.5 ~ 20 ,u and polyme-thylmethacrylate having a gr.~n size of 0 . 5 - 20 ,u, developing promotors, e.g. benzyl alcohol and a polyoxye-thylene series com-pouncl wllich ln.~y b~ added in t,he l~rocessing bath.
In accordance wi-th the process of the inven-tion, there is ob-tained a high contrast silver image~ The invention is -therefore appllcable to various fields wherein a high contrast black and white recording is required . The light- sensitive mate-rial of the invention i s, for examplc, applied pr~Eerably to a ] 0 printing- or micro-sensitive material.
The process of the inven-tion for forming a lith type pho-tographic image has superior charaeterist ics which no conven-1: iona:l proce3~;e,C; havc~ r~ached y~t .
i s no t nc~c~ ~ s ~ ~ ri l y e l uc i d.~ cl wh y t'he 'h i cJh c o rl -trast silver image may be obtained aceordiny to the process of the invention. It is presurned that the semiquinone produced by oxidation of ~ydroquinone in the developing solution by the tetra-zolium compound may be aeeumulated in an abnormally high concentra-tion near the developecl silver.
It is said, in yeneral, that the so-called "infectious pherlom~norl" cloes not taho plclCe due to instantaneous rernoval of the semic~uinone or cLuinones b~ sull~onation when the sulfite ions are in a high eoneentration in the developing solution. Whereas, in the present proeess, it is presurned as iE the infeetious deve-lopment takes plaee at the position of -the exposed silver halide in the gelatin layer due to predorLIinant supply o-f the semiquinone.
I t is aeeordingly essential in the process of the invention to treat with a developing solution contai ning a hydro-quinone developing agent., The lith -type developing solution (in- ' fectious developing solution), however, is not essentially requir-ed as far as the solution is of h,ydroquinones, by wllich hiyh con--trast lith type silver imaye may sufficiently he obtained even : . :

.
.

in the presence of sulfite ion in a high concentration.
The process of the invention differs apparently from the conventional processes in that no conventional lith type developing solution which contains hydroquinone, alkali, alkali metal bromide, sulfite ion in low concentration, and as a preser-ver a condensation product of formaldehyde/sodium bisulfite or carbonylbisulfite amine ls needed, although the use of such com-ponen-ts may of course be possible.
As the hydroquinone type developing agents employed in the invention are mentioned, e.g. hydroquinone, chlorohydroqui-none, bromohy~roquinone, isopropylhydroquinone, toluhydroquinone, metylhydroquinone, 2,3-dichlorohydroquinone, 2,5-diMethylhydro-~uinone, 2,3-dibromohydroquinonc, 2,5-dihydroxyacetophe~none, 2,5-diethy:Lhydroquinone, 2,5-di-p-phenethylhydroqu:inone, 2,5-dibenzo-ylaminohydroquinone, and the like.
The developing solution containing the hydroquinones developing agent employed in the invention includes not only the so-called lith type developing agent but also the gradient ~Q

and PQ developing solutDn, the la-tters of which are advan-tageously employed in the invention because of the easiness of preparation and ~uperior preservability. ~mong these developing solutions, those which sho~ the superadditivity are preferred. For example, the developing agents and the additives thereEor described in "The Theory of Photographic Process'!, Third Edition, pp 374-378 (1966) are advantageously employed. A preserver like sulfite salts such as sodium sulfite, potassium sulfite or ammonium sulfi-te may jointly bc employed in the developing solution used in the inven-tion without impairing the effect of the invention; and this is another characteristic of the invention. The adjustement of pH
and giving a buffer function with an alkali hydroxide, alkali carbonate or amine, or addition of inorganic development retarder such as potassium bromide or of organic developmen-t retarder such

8~L

as benzotriazole may optionally be carried out as in the standard black and white developing solution. :~
In the invention the phrase "-trea-t with a develop~
ing solution containincJ hy~roquinones developing agont" m~ans to carry out development of the exposed material of the invention with the developing solution which satisfies the above-mentioned - -conditions, and various modes may be included therein. For exam- :
ple, the temperature at which developmen-t is carried Ollt is pre~
ferably below 50~C, more preferah]y around 30~C', and the time re~uired for development is general]y within 30 minutes, more preferably within S minutes, by which good results are obtained in general.
~ r the cleveloprnent;, the subsec1uen~ prc.~ces.ses ';uch as washirlg, s~oppirlcJ, st:abi.li~ cJ ancl.f.ixi.nq are c~arrled out. :~.E
necessary,processes like prehardening and neutralization and the li~e may be adopted, but they may optionally be omitted. ~e pro-cesses may be carried ou-t either by the so-called r~nual treatment e a bath- or tray-development or by -t'ne mechanical -treatmen-t like a rollar- or hanger-development. According to a preferrcd ?.0 embodimen~ of the :invention, the proc:essing solutlorl in the bath dev~lopmen-t was more than 20 times st:abler over long perlod than the convention li-th type developing solution. '~:specially, when the known particular developing solution con-taining sulfite ion in an extremely low concentration is em~loyed in order -to impro-ve the dot quality o the lith type light-sensitive material, it became of no use for several hours. While, accordlng to a preferred method o~ the invention, the processiny solution coulcl be s-tably ernployed after one month has passed, and the dot qual:ity using the solution was then comparable to that using a newly prepared solution.

Furthermore, addition of a contrast agerlt often used for -the conventional higll contrast developing solu-ti.on to the .
--22- ~
.

developing solution employed in the invention gives no undesirable influence on the photographic quality.
As can be clearly understood by the explanations given above, the invention relates to a novel l:ight-sensitive silver ha-lide photographic material and the processing method thereof which may obtain a superior line- or dot-image by processing the light-sensitive silver halide photographic material comprising a tetrazo-lium salt and a silver halide having a narrow grain si~e distributio tion, with a developing solution containing hydroquinone, using no infectious developing solution.
According to the process of the invention, there is ob-tained a high contrast silver image even when the diffusible tetra-zolium compound is employecl. ~ere may also be obtained a dot ima~
y~ which is ~uper:ior to that obtained by the method desaribed in G~rman Patent No. 2,63~,666, publi~hecl on February 7,:L977, when the non-dif~usible tetrazolium compound is employed.
The invention is further concretely explained by the fol-lowing Examples, which by no means restrict the scope of the inven-tion:

A silver chloroiodobromide-gelatin emulsion comprising silver hallde of ~0 mole % chloride, 19 rnole % brGmide and 1 mole % iodide, having an average grain size of 0.3 u and of 80 % grains within a range of 0.26 - t).36 ~ was sensitized chemically with sulfur- and gold-sens!itizers. To the emulsion were added polyethy-leneglycoln (m.w. - 1540) oleic acid ether in an amount of 200 mg -~
per mole of silver , and further 4-hydroxy-6-methyl-1,3,a,7-tetraa-~aindene and spiro-bis ( 3,3-dimethyl-5,6-d:ihydroxyinclane ) in a-mounts of 100 mg and 20 mg per mole of silver respectively. The emulsion was coated on a polyethylene terephthalate support in such amounts that those of the silver and the ~elatin were 55 mg per 100 cm2, respectively . Further, on the silver halide emulsion layer, was coated gelatin in an amount of 30 mg per lt)0 cm2 as a :
protective layer. The above-mentioned elements were wedge-ex-posed with a tungsten lamp through a gray contact screen and then - processed at 30C according to the following processes :
Developing : 1.5 min. - -Stop fixing : 2 min.
Washing : 5 min.
Drying.
The following compositions were employed in the processing bath:
~Developing solu-tion~
Metol 3.5 g Anhydrous sodium sulfite 60 g ~Iydroquinone 9.0 g Sodiurn car~onate 54 y Pota8sium ~)romide2.5 y 5-Nitrobenzimidazole0.5 g l-Phenyl-5-mercaptotetra-20 g .~ :
zole . .
Waterto make 1 litre (pH=
10.25) ~Stop fixer]
Ammonium thiosulfate decahydrate 150 mg Anhydrous 80dium sulfite 10 g Sodium acetate trihydrate 15 g Glacial ace tic acid 15 ml Water to make 1 litre :
(pII=4.20) Comparison 1 was repeated, except that potassium dichro-mate was added, in advance of coating, to the emulslon in an a-mount of 4 g per mole of silver.

-2~-.

i34 COMP~RISO~J 3 Comparison 2 was repeated, except that potassium persul-fate was added, in advance of coating, to -the emulsion in an a-mount of 4.0 g per rnole of silver instead of potassium dichromate used in Comparison 2.
EXAMPL~ 1 A material was prepared in the similar rnanrler as in Com-parison 1, except that 2,3,5-triphenyl tetrazolium chloride (Com-pound (1)) was added, in advance of coating, to the emulsion in an amount of 4.5 g per mole of silver instead of potassium dichro-mate usecl in Comparison 1.
~X~MI'LE 2 ~ rnateri.,~l was prepared :i.n t:he si.m:i:lar manr~e.r as :i.n Com-parisvn 1, exc~pt that 3-(p-hyclroxyphenyl)-5-lnethyl-2-phenyl-2l-I-tetrazolium chloride (Compound (1~3)) was added, in advance of coat-ing, to the emulsion in an amount of 4.0 g per mole of silver instead of potassium di.chromate u~ed in Comparison 1.
E ~ ~PLE 3 material was prepared in the similar manner as in Com-pari~,on 1, cxcept that 2,3-diphenyl-5-ethyl-2H-tetrazolium chlori-de (Cornpound (7)) was addcd, in advance o:~ coat:i.nc~, to the ernulsion in an amount of ~.0 g per rnole o s:ilver instead of po-tassiurn di-chromate used in Comparison 1.
F,XAMPLE 4 A material was prepared in the similar manner as in Comparison 1, except that a non-diffusible tetrazolium compound tCompound(66)) synthesized from 2,3-diphenyl-5-nitro-2H--tetrazo-lium chloride and polyacrylic acid was added, in advance of coat-ing, -to the emulsion in an amount of 8 g per mole of silver instead of potassium dichromate used in Comparison 1.

The results of Comparison 1 to 3, and Examples 1 to 4 are summarized in Table 1.

Table 1 Photographic Relative Dot performance sensi-tivity r Fo~ quality Sample Comparison 1 100 6.42 0.06 2.0 " 2 91 6.74 0.04 2.5 " 3 89 6.66 0.04 2.5 Example 1 80 10.22 0.04 3.5 " 2 83 9.87 0.04 3.0 " 3 85 10.03 0.0~ 3.5 .
" 4 92 12.85 0.0~ 5.0 As clearly shown in 'L'clb:le l, t:he mat~rial. accoxding to ~ i.nventi.on i.n~reas~s conlx~st vc?ry efEect::iv~:l.y all(l havo a clot qua:L:ity supcrior to okher knowrl ox.i.(l:i7~i.ncJ ac~t?nls everl wh~rl pro-cessed with the MQ cleveloping solution, and therelore, has supe-rior properti.es for the lith type ligh-t-sensitive material for the line- and dot-image use. }Iere, the -term "dot quality" means 20 an ~valuat.ion value for the reproduction c~uality of the half tone image.
The 1l lith type" pho-tographic ~lement (exposed usin~ a ha:lf tone .imay~ and cleveloped ) produc~s usu~lly a part call~d ".~hadow dot" and a part called "hicJhtlight part`'.
The intermediate part which is between the two parts has various sizes. The term "dot quality" re~erred to herein means an evaluation value of a part called "50 % dot" i.e. the concen-tration at which 50 % is developed, and is expressed by a progressiv ve scale. Namely "4" means to be excellent and "l" means to be 30 extremely bad. It is not normally allowed -that the 50O dot quality is less than '3".
It has turned out, among the above-ment:iorled mater.ials accordin~ to the invention, the use o:E -the di~usihle tetrazolium salt (Exar.~ples 1, 2 and 3) produces an slightl-y lower- ~-value ancl clot quality, but o:E a rather superior charact:eristics for the . -26-S~4 reproduction of the line image, as compared with the use of the non-diffusible tetrazolium salt (The characteristic of line image was estimated visually by the reproducibility of the Chinese cha-racter "UTSU".) A silver chloroiodobromide/gelatin emulsion comprising silver halide of 50 mole % chloride, 49 mole % bromide and l mole % iodide, having an average grain size of 0.25,u and 75.P/O grain within a range of 0.23 - 0.28,u was sensitized chemically with sulfur- and gold-sensitizers. To the emulsion were added polyethy-leneglycol (m.w.-1420) oleic acid ether in an amount of 200 mg per mole of silver, and further ~-hydroxy-6-methyl-1,3,3a,7-tetrazxain-~erle :in an amount o:E 300 mcJ ~er mo:le oE silvcr. rL'II~ emu:L.~;i.on wc~s coatccl on a polyethy:Lerle tetrclphta:Late suppo r t .i n suc h ~lmoullt~

that those oE the silver and the gelatin were 55 mg and 50 mg per 100 cm , respectively.
Further, on the silver halide emulsion layer, was coated gelatin in an amount of 30 mg per 100 cm as a pro-tec-tive layer.

The above-mentioned material was wedge-exposed with a tungsten lamp throuyh ~ gray contac-t screen and then processed at 30f'C accord-~ny to the followiny process~s:
Developing : 2 rnin.
S-top fixing : 2 min.
Washing : 5 min.
Drying.
q~re processing bath was composod as follows:
¦Developing solution~

Formaldehyde/sodium acid sulfite adduct 50 g Hydroquinone 15 g Boric acid 8 g Anhydrous sodi~n sulflte 2 g Sodium carbonate rnonohydrate 85 g Potassium bromide 2.5 g 6-Ni-troindazole 0.1 g Water to make 1 litre ~pH=10.00) The same cornposition as in Comparison 1 was errlployed for the Eixing solution.

Comparison 4 was repeated, except that hexaam:ine cobalt chloride ~.~ias added, in advance of coat:iny, to the emu:Lsion in an amount of 3 g per mole of silver and that -the following processing bath composition was employed:
,~eveloE~ing solution ,7 , . ' M~ o1. 3.5 CJ

~n~ o~:iurn c~,u:L.(ik~ 0 IIydroctui. nolle 9 ~ O c~
Sodium carbonate monohydrate 54 Potassium bromide 2.5 g 6-l~itroinda~ole 0.1 g Water to ma~e :L li-tre (plI=10.25) Z~o COMPARISON 6 Comp~ri.son 5 wax repeatecl, except -that Chloxamine T (to-sylchlo.ramide sod:ium) was add~d, .in aclvance o~ coatirlcJ, to the emulsi.on in amount of 3 y per mole of silver ins~ead of hexaami-ne cobal-t chloride used in Comparison 5.

Comparison 5 was repea-ted, except tha-t 2,5-diphenyl-3-~-naphthyltetrazolium chloride (compound (34)) was added, in advance oE coating, to the emulsion in an anount of 4 g per mole of silver instead of hexaamine cobalt chloride usecl :in Comparison 5 Compari.son 5 was repeated, excempted -that: :3,3'-(3,3'-dimethoxy-4,4'-diphenylene)-2,2',5,5'-phenyltetra-di-(2H-tetra-. -2~-zolium chloride)(Compound (35)) was added, in advance of coating, -to the emulsion in an amount of 2 g per rnole of cilver instead of hexaarrline cobalt chLoride used in Comparison 5.
EX~MPLE 7 Example 6 was repeated, except that sodi~t dibutyl-hexyl-succinate sulfonate was fur-ther added in an amount of 1 g per li-tre to the developing solution used in Comparison 5.
The results of Comparison 4 -to 6 and Examples 5 to 7 are swnmarized in Tablc! 2.
Table 2 ~~ ~ ~
pllo~:o~r~?~ ~c~ D~t ~e.rS.orlnarlce Se~ls:i t.i.V~ ,y ~f F~og c{uali ty Salnp:Le .

'omparison 4 100 4.40 0.06 2.0 ,. 5 93 5.97 0.08 2.5 ~' 6 88 6.02 0.0~3 ~ 2.5 E~ample 5 82 7.97 0.08 ¦1 3-5 " 6 85 8.21 0.06 3.0 _ " 7 ~5 ~.7~ 0.06 ~ s clearly shown in Table 2, a hi~l contrast image with a good dot quality is obtained even when the tetrazoliurn salt, arnong substantially the diffusible oxidizing agents, is trea-ted with the MQ developing solution.

A silver iodobromide/gelatin emulsion comprising silver halide of 98 mole% bromide and 2 mole% iodide, having an average grain size of 0.4 ,u and 75 % grains within a range of 0.36 - 0.44 ,u, with a ~1Ø0~ face was sensit~zed chemically with sulfur- and gold sensitizers. To the emulsion was addecd 4-hydroxy-6-methyl~l, 3,3a,7--tetraazainclene in an amount of 500 mg per mole of silver.

The emulsion was coated on a polyethylene terephtalate support in such amounts -that these of silver and the gelatin were 30 mg and 30 mg per 100 cm2 respectively. Further gelatin was coated on the impulsion in an amount of 30 mg per 100 cm as a protec-tive layer.
The above-mentioned material was wedge-exposed with a tungsten lamp and then processed at 30C according to the follo-wing processes:
Developing : 2 min.
Stop fixing : 2 min.
Washing : 5 min.
Drying.
The processing bath was composed as follows:
. .
Develop:irlg solut:ion ¦
Metol 1.0 g Anhydrous sodium bisulfite 75.0 g Hydroquinone 9.0 g Sodiurn carbonate monohydrate 29.0 g Potassium bromide ~.0 g Water to rna]ce 1 :Litre (pH=10.00) The sarnc composition as in Compar:i~son L was employed for the fixing solution.
COMP~RISON 8 Comparison 7 was repeated except tha-t in advance of coating of the emulsion a gelatin layer (40 mg of gelatin per 100 cm2) containing a ferric sodium complex of e-thylenediamine-tctraacetic acid in an arnount of 4 g pcr molc o~ silvcr was coatcd ; on -the polyethylene terephtalate support.

Comparison 8 was repeated except that in advance of coating of the emulsion a gela-tin layer (40 mg of gelatin per 100 cm ) containing 2 3 5-triphenyltetrazolium chloride (Com-4~

pound (3)) in an amount of 40 g per mole of silver was coated on the support instead of the ferric sodium complex of ethylene-dia-minetetraacetic acid.
The results of Comparisons 7 and 8 to Example 8 are summarized in Table 3.
Table 3 Photographic Relative Y Fog ~esolving perfonnanceSensitivity power (line/mm) Sample Comparison 7 100 2.61 0.0~ 200 " ~ 97 3.96 0.0~ 2';0 Exarnplc~ ~ ~1 6.2~ 0.0~ 30U

As clearly shown in I'able ~ light-sensitive material according to the invention possesses superior image characteristics for the high contrast light-sensitive silver halide ma-terial.

To 100 m~of 10 % gelatin solution kept at 40C was added 10 m~ o~ L0 % 2,3,5~tripherlyltetrazoliurn chloricle (here:inafter Leferred to as "T-Salt"). To the solution was adde~ diethyLhexyl-succina-te sulfonic acid (hereinafter referred to as "DES"~under vigorous stirring. ~fter cooling, the mixture was made into a noddle-like mass and washed with washing water until no chlori~
de ion was detected. The mixture contained (Compound (39)) and was redissolved and finally made up to 200 m~ with water. It was then coated on a polyethylene terephthalate support in an a-mount of abou-t 2.0 mg per 100 cm2, based on the T-Sal-t. On the layer was coated a lith type silver chlorobromide emulsion com- -prising silver halide of 70 mole % silver chloride and 30 mole %
silver bromide, and having an average grain size of 0~25 ,u and about 80 % grains ~ithin a range of 0.19 - 0.31,u, in such amounts that those of the silver and the gelatin were 55 mg and 50 mg per 100 cm2, respectively, to prepare Sample A. To the Sample A was coated gelatin wi-th a thickness of l.S,u -to prepare Sample B.
After drying, Samples A and B were wedge-exposed with a tungsten lamp through a gray contact screen and then processed at 30C
according to the following processes:
Developing : 1 min., 1.5., 2 min., 2.5 rnin.
S-topping : 1 min.
Fixing : 2 min.
Washing : 5 min.
Drying.
The ~ollowiny compositlons wer~ ~rnploy~!cl clS the process-:iny ~olutions:
DevQloping solution Metol 3.5 g Anhydrous sodium sulfite40 g "
Hydroquinone 9.0 g Sodium carbonate monohydrate 50 g Potassium bromide 2.5 g 5-Nitrobenzimidazole 0.5 g l-Phenyl-5-rnercaptotetrazole 10 rng Water ko make 1 li-tre (pll=10.25) Fixing solution ; Arnmonium thisulfate decahydrate 150 g Anhydrous sodiwm sulflte 10 g Anhydrous sodiwn phosphatc 15 g Water to make 1 litre (pH=6.20) The results of Example 9 are summarized in Table 4.

Table 4 Photographic Development Dot Dot - performance Tirne (min.) quality stability Sample -Sample A 1 3.0 poor " 1.5 3.5 good " 2 3.0 poor " 2.5 3.0 poor Sample B 1 3.5 good " 1.5 4.5 excellen-t " 2 4.5 excellent " 2.5 3.5 yood ~s shown :in rrable ~, garnple B having the binding upper Lay~r ~ows :L~ss changes in dot: clualLty and dot stabil:ity, depending on the change of the development oE tirne ancl possesses a lit-tle better dot quality, as compared with Sample A

having no binding upper layer. Here, the term "dot stability"
means a regularity of the dot quality from small dot at slightly exposed part to large dot at highly exposéd part and is expressed as "excellent" if regular, and as "poor", iE irregular, by a -three B t~g~ ~va luation.
EX~MPLE 10 A silver halide emulsion containing silver halide of 80 rnole~ chloride and 50 mole % bromide, having an average grain size of 0.18 ~ and 75 % grains within a range of 0.11 - 0.25 ~ was chernicàlly sensitized with a fold sensitizer and thiosulfate. Then, ~ -thereinto were added the following:

4-Hydroxy-6-methyl-1,3,3a,7-tetraazaindene 0.78 g Saponin 2.5 g Formaldehyde 0.5 g 2,3,5-triphenyl-2~-tetrazolium-. .

di-isopropylnaphalene-disulfona-te 1~2 g The thus prepared emulsion, was coated on a polyethyle-neterephtalate support in such amoun-ts that those on the silver and the gelatin were respectively 40 mg per 100 cm2 and 22 mg per 100 cm2 Furthermore, gelatin was coa-ted t:hereon as a protec-tive layer in an amount of 10 mg per 100 cm2. An exposure and process-ing were carried out i.n the same method as in Comparison 7.
~OMAPP~ISON 9 The emulsion was prepared and processed in the same method as in Example 10 except that the silver halide was of 1.65 JU in an average grain size and the 25% grains thereof were wi-thin a rancJe of .L~0 - 2.3 The resu:lt~ of Colnparison 9 and Exarnp:Le :L0 are showr :in Table 5.
Table 5 Photographic Relative Fog r Dot performance Sensitivity quality Sample Comparison 9 100 0.05 7.01 2~5 Example 10 75 0.04 11.72 ~.O

As clear from the above, the sample of the invention is understood as excellently improved in dot quality and high con-trast.

-3~_

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A light-sensitive silver halide photographic material which consists essentially of a support, at least one hydro-philic colloidal layer coated thereon containing silver halide grains having an average grain size of from 0.05 to 1.5 µ and at least 75% of which grains being within a range of from 0.6 to 1.4 times said average grain size, and a tetrazolium com-pound selected from the group consisting of a compound of formulae [I], [II] or [III]:

[I]

[II]

[III]

wherein R1, R3, R4, R5, R8, R9, R10 and R11 each represent an aryl group or a heterocyclic group; R2, R6 and R7 each represents an aryl group, a heterocyclic group, an alkyl group, hydroxyl, carboxyl or the salt thereof, an amino group, mercapto, nitro or hydrogen;
D represents a divalent aromatic group; E represents an alkylene group, an arylene group or an aralkylene group; X is an anion; said heterocyclic group being selected from the group consisting of a thiadiazolyl group, a benzothiadiazolyl group, an oxazolyl group, a pyrimidinyl group, a pyridyl group and a 2,5-dlmethyl-thiazolyl group; and n is 1 or 2, provided that the compound forms an intramolecular salt when n is 1.

2. A light-sensitive silver halide photographic material according to Claim 1 which material is to be treated with a developing solution containing a hydroquinone and Metol or phenidone and consists essentially of a support, at least one hydrophilic colloidal layer coated thereon containing silver halide grains having an average grain size of from 0.05 to 1.5 µ
and at least 75% of which grains being within a range of from 0.6 to 1.4 times said average grain size, and a tetrazolium compound selected from the group consisting of a compound of formulae [I], [II] or [III]:

[I]

[II]

[III]

wherein R1, R3, R4, R5, R8, R9, R10 and R11 each represents an aryl group or a heterocyclic group;
R2, R6 and R7 each represents an aryl group, a heterocyclic group, an alkyl group, hydroxyl, carboxyl or the salt thereof, an amino group, mercapto, nitro or hydrogen; D represents a divalent aromatic group; E represents an alkylene group, an arylene group or an aralkylene group;
.gamma. is an anion; said hetorocyclic group being selected from the group consisting of a thiadiazolyl group, a benzothiadiazolyl group, an oxazolyl group, a pyrimidinyl group, a pyridyl group and a 2,5-dimethyl-thiazolyl group; and n is 1 or 2, provided that the compound forms an intramolecular salt when n is 1.

3. A light-sensitive silver halide photographic material according to Claim 1 wherein the tetrazolium compound is non-diffusible.

4. A light-sensitive silver halide photographic material according to Claim 1 wherein the tetrazolium compound is diffusible.

5. A light-sensitive silver halide photographic material according to Claim 1 wherein the hydrophilic colloidal layer is a gelatin layer.

6. A light-sensitive silver halide photographic material according to Claim 1, wherein the silver halide has an average grain size of from 0.1 to 0.5 µ and at least 80%
grains are within a range of from 0.7 to 1.3 times said average grain size, the silver halide being silver chlorobromide or chloroiodobromide containing at least 50 mole % silver chloride.

7. A light-sensitive silver halide photographic material according to Claim 1 wherein the tetrazolium compound is present in the at least one hydrophilic colloidal layer.

8. A light-sensitive silver halide photographic material according to Claim 1 wherein the photographic material further comprises a gelatin layer adjacent to the at least one hydro-philic layer, the compound being present in the gelatin layer.

9. A light-sensitive silver halide photographic material according to Claim 1 wherein the cation moiety of the tetra-zolium compound is selected from the group consisting of the following:
(1) 2-(Benzothiazol-2-yl)-3-phenyl-5-dodecyl-2H-tetraazolium (2) 2,3-Diphenyl-5-(4-t-octyloxyphenyl)-2H-tetrazoliuum (3) 2,3,5-Triphenyl-2h-tetrazolium (4) 2,3,5-Tri(p-carboxyethylphenyl)-2H-tetrazolium (5) 2-(Benzothiazol-2-yl)-3-phenyl-5-(o-chlorophenyl)-2H-tetrazolium (6) 2,3-Diphenyl-2H tetrazolium (7) 2,3-Diphenyl-5-methyl-2H-tetrazolium (8) 3-(p-Hydroxyphenyl)-5-methyl-2-phenyl-2H-tetrazolium (9) 2,3-Diphenyl-5-ethyl-2H-tetrazolium (10) 2,3-Diphenyl-5-n-hexyl-2H-tetrazolium (11) 5-Cyano-2,3-diphenyl-2H-tetrazolium (12) 2-(Benzothiazol-2-yl)-5-phenyl-3-(4-tolyl)-2H-tetrazolium (13) 2-(Benzothiazol-2-yl)-5-(4-chlorophenyl)-3-(4-nitro-phenyl)-2H-tetrazolium (14) 5-Ethoxycarbonyl-2,3-di(3-nitrophenyl)-2H-tetrazolium (15) 5-Acetyl-2,3-di(p-ethoxyphenyl)-2H-tetrazolium (16) 2,5-Diphenyl-3-(p-tolyl)-2H-tetrazolium (17) 2,5-Diphenyl-3-(p-iodophenyl)-2H-tetrazolium (18) 2,3-Diphenyl-5-(p-diphenyl)-2H-tctrazolium (19) 5-(p-Bromophenyl)-2-phenyl-3-(2,4,6-trichlorophenyl)-2H-tetrazolium (20) 3-(p-Hydroxyphenyl)-5-(p-nitrophenyl)-2-phenyl-2H-tetrazoliurn (21) 5-(3,4-Dimethoxyphenyl)-3-(2-ethoxyphenyl)-2-(4-methoxyphenyl)-2H-tetrazolium (22) 5-(4-Cyanophenyl)-2,3-diphenyl-2H-tetrazolium (23) 3-(p-Acetamidophenyl)-2,5-diphenyl-2H-tetrazolium (24) 5-Acetyl-2,3-diphenyl-2H-tetrazolium (25) 5-(Fur-2-yl)-2,3-diphenyl-2H-tetrazolium (26) 5-(Thien-2-yl)-2,3-diphenyl-2H-tetrazolium (27) 2,3-Diphenyl-5-(pyrid-4-yl)-2H-tetrazolium (28) 2,3-Diphenyl-5-(quinol-2-yl)-2H-tetraxolium (29) 2,3-Diphenyl-5-(benzoxazol-2-yl)-2H-tetrazolium (30) 2,3-Diphenyl-5-nitro-2H-tetrazolium (31) 2,2',3,3'-Tetraphenyl-5,5'-1,4-butylene-di-(2H-tetrazolium) (32) 2,2',3,3'-Tetraphenyl-5,5'-p-phenylene-di-(2H-tetrazolium) (33) 2-(4,5-Dimethylthiazol-2-yl)-3,5-diphenyl-2H-tetrazolium (34) 3,5-Diphenyl-2-(triazin-2-yl)-2H-tetrazolium (35) 2-(Benzothiazol-2-yl)-3-(4-methoxyphenyl)-5-phenyl-2H-tetrazolium (36) 2,5-Diphenyl-3-a-naphthyl-2H-tetrazolium (37) 3,3'-(3,3'-Dimethoxy-4,4'-diphenylene-2,2',5,5'-tetraphenyl-di-(2H-tetrazolium)

10. A light-sensitive silver halide photographic material according to Claim 1 wherein the light-sensitive silver halide photographic material further comprises an outermost gelatin protective layer having a thickness of from 0.1 to 10 µ on the hydrophilic colloidal layer.

11. A method of processing a light-sensitive silver halide photographic material, after imagewise exposure to light, with a developing solution containing a hydroquinone and Metol or phenidone, which material consists essentially of a support, at least one hydrophilic colloidal layer containing silver halide grains having an average grain size of from 0.05 to 1.5 µ
and at least 75% grains being from 0.6 to 1.4 times the average grain size, and a tetrazolium compound selected from the group consisting of a compound of formulae [I], [II] or [III]:

[I]

[II]

[III]

wherein R1, R3, R4, R5, R8, R9, R10 and R11 each represents an aryl group or a heterocyclic group;
R2, R6 and R7 each represents an aryl group, a heterocyclic group, an alkyl group, hydroxyl, carboxyl or the salt thereof, an amino group, mercapto, nitro or hydrogen; D represents a divalent aromatic group; E represents an alkylene group, an arylene group or an aralkylene group;
X is an anion; said heterocyclic group being selected from the group consisting of a thiadiazolyl group, a benzothiadiazolyl group, an oxazolyl group, a pyrimidinyl group, a pyridyl group and a 2,5-dimethyl-thiazolyl group; and n is 1 or 2, provided that the compound forms an intramolecular salt when n is 1.

12. A method according to Claim 11 wherein the developing solution contains a sulfite salt in an amount of more than 10 g. per litre.

13. A method according to Claim 12 wherein the pH-value of the developing solution is 8.5 to 12.

14. A method according to Claim 11 wherein the silver halide grains have an average grain size of from 0.1 to 0.5 µ, at least 80% grains being within a range of from 0.7 to 1.3 times the average grain size, the silver halide being silver chlorobromide or chloroiodobromide containing at least 50 mole % silver chloride, and the photographic material comprising a protective gelatin layer having a thickness of from 0.4 to 1.2 µ.