DE2154075C3 - Direct positive silver halide photographic emulsion - Google Patents

Description

C CH, -R '

• -N

(CU,), X

CO

Ϊ C (( ■ II,), N- ' I. KII (ΠΙ,), (O co R. ί
R. where mean:

: x

the one to complete an imtdazole. Oxazole, thiazole or sclenazole rings required borrowed atoms:

a hydrogen atom or an optionally substituted short-term alkyl or aryl radical; a hydrogen atom or an optionally substituted short-chain alkyl. Aryl or aryloxyrcsi and
X ° an anion.

2. Silver halide emulsion according to claim I. characterized in that it is 0.2 to 1.4 g Contains a concentration of substances per mole of silver halide.

3. Silver halide emulsion according to claim 1 and 2, characterized in that it is a color coupler ciil holds.

4. .Silver halide emulsion according to claims I to 3. thereby gckcnn / calibrated. that they are made from a gelatin Silver bromide iodide demilution exists.

5. Silver halide emulsion according to Claims I to 4. characterized in that sir as wear food contains:

5-Chlüru-J- (2-furmyki [hyl) -2-iiiulhylbün / o ·

(hiazolitimbroiiiid;
3- (2-formylethyl) -5-methoxy-2-nicthylbenzo-

thiazoliunibromide;
3- (2-Acetyliilhyl) -2-propylbenzothiazolium

bromide;
3- (2-formylethyl) -2-methylnaphiho-

[2,3 tl] thiazolium bromide;

3- (2Aceiyl; ithyl) -2-phenoxymethylbenzo-

thia / oliunibroniid:
2,2-ethylene-bis [3- (2-acceiylethyl) ben / o-

thia / olium brumid];
2-ßenzyl-3- (2-propionylethyl) benzo-

thia «) liumbroniid;
3- (2-AcetyIathyl) -2-ethylbenzothiazolium-

bromide:
3- (2-acetylethyl) -2-benzylbenzoselen-

azolium bromide:
3- (2-AcetyIäihyI) -2-ben / yI-5-phenyl-

benzoxa / oliumbroniid or
3- (2-Benzoylethyl) -2-ethylbenzothiazolium-

bromide:
3- (2-formylethyl) -2-methylbenzoihiazolium-

bromide;
3- (2-Acetylethyl) -2-benzylbenzothiazolium-

bromide:

3- (2-Formylaihyl) -2-propylbenzoihiazolium bromide

The l.rfindiing bclnlll cmc dircklpusilive phologia phischc silver halide emulsion, the latent images for predominantly in the interior of the silver halide cores ner ores · ;! and contains a masking agent.

Ks' is known to be so-called direct positive pholographic silver halide emulsions for Her production of positive pholographic images in a direct way. il. H. without using a photographic negative put, use k.inn.

These direct positive pholographic emulsions produce latent images on exposure for the most part in the interior of the silver halide grains ner. The creation of direct positive pholographic Pictures is thereby caused by the fact that the not exposed districts of a direklpositiven photograph! see emulsion layer being selectively obscured and that corresponding to the unexposed, veiled areas a normal pholographic silver image is being developed. The Schleicrungsmillel can be used in a so-called "concealment bath" Twist with which the pictorial exposed silver halide emulsion layer in front of the Image development is dealt with. On the other hand, it can Concealers also used in the developer solution Applied or applied to the I Imkchremiil sion must be incorporated before it is applied to a layer support.

The well-known compounds that form wear and tear generally consist of llvdrazinverbindii.igeii Be it, for example, from the HS l'Si'ihi 7H "), in particular columns I./eile IK to J4 and columns i. / Eile 2" to column ^r >, / hurry 2 !. known to use llvdriizinverbindiingcn .ils fogging agent with the syllable halide UV solution from the surface, f) it is further for example from the I ¹ S IVS 2 ') «8 ^l ) 82, in particular Col. I . / rush 21 to J4 and column 4. / rush I to column ^r >. / rush ^r > 2 known.

Ilydtii / invcrbindiingcn nh VmthkicrungMimid in .Silver halide solutions of the surface type or to use in the emulsion itself.

The disadvantage of using the known hydrazine compounds as wear mills is that that they, especially when they are incorporated into the silver halide emulsion itself, for Achieving a sufficient formation of the tench in relative

T
21 54
3 or 5 075
4th liplien concentrations must be applied. where mean: / “B. in concentrations of 2 g per mol of silver halogens
nid, as can be seen, for example, from LJS-PS 25 88 982
results. When using such high con / entraiinen IO Z which to complete an imidazole, oxazole,
Thiazole or Selennz.olringes required ato is it difficult to get uniform sensitometrically !? Result
nits to achieve, and that's because they are larger ; I (K 11.1. C; me;
R a hydrogen camouflage or one if necessary Amounts of wear and tear in the wrapper
solution, where they discolour the photographic
different materials in the sewing picture background districts substituted short-chain alkyl or aryl radical;
R 'represents a hydrogen atom or optionally one
substituted short-chain alkyl, aryl or cause. * "■ N N- ' Aryloxy radical and Presumably the necessity of using is based I I X ^s an anion. generation of high concentrations of the known (Cl !,), (CIl,), 2X 15th Typical rings that Z can stand for are Obscurants care that these compounds I "'!" for example: not or only weakly from the silver halide grains CO CO Benzimidazole rings, e.g. B. are adsorbed. The migration of the veils I I 5-chlorobenzimidazole rings or The agent in the developer solution is not just carried through R R Naphthimidazole rings: the high concentration in which the compounds are in the 20th Oxazole rings, e.g. B. Emulsion present, promoted, but rather also 4-methyloxazole-, 5-meihyloxazole-. by using these compounds 4-phenyloxizole, 4,5-diphenyloxazole, necessary high pH that normally 4Äth \ lo \ az () l-. 4.5-DirnethyloMi / cil- and above 12, in which the bolt is at 12 to Π and the 5-phen \ lo \ azole rings: egg 'is necessary. around ei ml · Vcischieicninsi within one 21 Ben / <> \ a / olringe. for example achieve an acceptable time span / u. Benzo \ .izole. 3-C chlorobenzoxazole ·. The task of the LiTindimg is. a direct positive 5-Meth \ lben / (i \ aziil ·. 5- Phenv! Benzoxazole ·. photographic silver halide emulsion, the lantern bMethylbenzox.izol. Pictures / around predominantly inside the 5.6-1) imeth \! Benzoxazole. Silver halide grains er / eugi. an / ugc'ien. which one JiI 4.b I) iineih>! Benzoxazole. such concealment was revealed in photogra 5 M ei hox ν benzoxazole. phic direct positive silver halide fluids in 5 Älhoxybcnzox.izol. J Chlorobenzoxazole. lower concentrations than previously used b Meihoxvbcn / oxazole. and discoloration when used 5-1 l \ drox \ benzc \ .i / <il or the non-image-I linteij. '.mdbe / irke must be avoided. C, fa-l l \ dnixvbcnzoxazole length: KS has been found to be certain excruciating Naphthoxazole rings. /. B. heterocyclic salts with an imida / ol-. Oxa / ol-, \ N.ιphlhox.ι / nlriHfre; Thia / ol- or Selena / olring herr.irraj: ·; rd effective Thia / olritige. / B. Represent obfuscation means. Thia / ol. 4 Melhvlthi.i / ol. The subject of the invention is thus a phologra III 4 Phenvjthia / nl-. ) Melhy! Lhia / oI-. phische dircklposilive silver halide emulsion, the 5-Phen \ lihiii / cil-. 4.5-I) imeth> lthia / ol-. latent images for the most part inside the 4. ¹ J Oiphenvlthia / ol and Silver halide grains and a fogging 4 (2 Ihierivljthia / olnnge: contains agent, which is characterized as Bcn / iilhiii / iilnnge. / B. Concealment agent 0.1 to l. ^r > g per MoI silver halo I ι Ben / olhia / <il. 4 Chlornben / oihia / iil-. contains a compound of the following I-formulas: 5 Chlorobeii / iiihia / iil. b C hlorobcn / dlhia / cil. , * '~ . ^ 7 C hlorohen / ulhia / ul. / \
/ · 4 Methvlben / iilhi, i / (il. '. C CII. R- ill ") Mclhvlhi'ii / iiihia / iil ■ b McilnlbcM / oilii.i / iil. ") Br <imiibcn / oihi, i / til. b Bifiiiuihen / iilhia / ol. ((II.I. X 4 PhcMvlhcii / oihiii / iil. > l'henvlben / fiihia / cil. (() i Methoxvbcn / (ilhi.i / <il. ¹ J Mclhiixvbcn / uihiazol. R. bMelhox \ ben / <ilhi.i / ol. 5) i) d (iben / iithia / ol. hl) b- | (idoben / (ithia / ol. 4 Alh (ixvben / olhia /! Il. 5 Atliox> ben / olhia / ol. Teiriihvdrobcn / dlhiii / dl-, ^r } Jb l) i (nethoxjben / (ithia / ol. St. 5-1 lydroxybcn / .othiaz.ol- and e-hydroxybenzolhiazole rings; Naphtholhiazole rings, e.g. B. ä-Naphthothia / .ol-, S-Mclhoxy-ic-naphthothia / .ol-. 7-methoxy-i \ -naphtholhiazole and Naplitho [2, l -dj-lhiaz.olringc;

Thit> naphihenu-7'.6 \ 4,5-ihiazole rings, e.g.

4'-Metho \ ythionaphtlieno-7 ', b, 4,5-lliiazole rings; Selenazole rings./. B.
4-methylene azole vein
4-PhenyUe | ena / ol rings:
Benzoselenazole rings, e.g. B.
Ben / oselena / ol-, S-Chlurnben / osclenazol-,
5-methoxybenzoselenazole,
5-1 lydruxybenzoselena / ol- or
Teirahydrobenzoselenazole rings, or
Naphthoselenazole rings. /. B.
ν naphthoselenazole rings.

The short-chain alkylsies represented by R and R ¹ preferably have 1 to 4 carbon atoms and thus consist, for example, of methyl, ethyl, propyl or butyl radicals. Of particular importance are compounds of the structural formula given, in which R and R ^! Represent alkyl radicals having 1 or 2 carbon atoms. If R and R ^{1 represent} substituted alkyl radicals. These exemplary WLMs can consist of aralk radicals. z. B. Benzvl-. Phenethyl or phenoxymethyl radicals.

Places R and R are optionally substituted aryl radicals these preferably consist of arylresias of the phenyl or naphthyl series with 6 to 10 Carbon atoms in the aryl group. The preferred aryl radical is the phenyl radical.

If R has the meaning of an aryloxy radical. so this preferably consists of an Arvloxvres: the Phenoxy or naphthoxy series with 6 to 10 Carbon atoms, Lin is the preferred aryloxy radical Phenoxyresl.

X 'can be, for example, a halide anion. z. B. a bromide. Chloride or odorous ion. a sulfate. Hydrogen sulfate or a short chain alkyl sulfate anion. for example a methyl sulfate or ethyl sulfal anion. an aromatic sulfonate anion. for example cm Toluenesulfonate or benzenesulfonate anion. an anion, which is derived from a carboxylic acid, for example an acetate. Trifluoroacctate or propionate anion or for example a perchlorate Cyunai-. Thiocyanates Sulfamate or benzoatamon.

As a particularly advantageous veil agent if such anions have been found to consist of halogenated anions

Particularly advantageous fasteners are for example the ones in lolgetuloM .mgcgcbcnen qti.i'eni.i for heterocyclic salts:

a) 3 (2 ion methyl) -2-methylben / oihi.i / olium.

b) 3 (2 Acetylatrvl) 2 bcnzvlbeii / othiiizoliiiiii-

c) } (2 I ormvlathyl) -2-pmpylbcnzothia / olium.

d) ϊ (chloro-j (2-formylethyl) 2-methylbenzothiazolium .

e) 3 (2 I ormylethyl) 5-methoxy-2-methylbenzo
thiazoli'.m ·.

f) 3 (2 acetylethyl) -2-propylbenzothiazolium.

g) 3 (2 I or my la thy I) 2 ■ met hy Ina ph t ho- [2.3 djthiazohum-.

h) 3 (2 Acelylethyl) 2-phenoxy met hy Ibenzo

thiazolium,
ι) 2.2'-ethylene bis [-J '(2-; icotylethyl) ben / .u ·

ihiazolium] -.

j) 2-benzyl-3- (2-propionylethyl) benzothiazolium,
k) 3- (2-AcctyläthyI) -2-ethylbenzothiazolium-,
I) 3- (2-Acetylethyl) -2-benzylbenzosclenazolium.
ni) 3- (2-Acclj lätliyl) -2-benzyI-5-phenylbenz-

oxazolium and
n) 3 (2-Benzoylalriyl) -2-ethylbenzoihiazolium salt c.

The fogging agents according to the invention can be me customary methods by reacting a C'yclammoniumhydrosalzes with a compound mil an active double bond sysieni, z. B. a -, iithyleniiichen double bond between the first and second carbon atom of an aliphatic molecule or radical.

The reaction can be carried out in an inert organic solvent as the reaction medium

in, in particular in an inert organic solvent with moderate polarity that dissolves both reaction components, but not a solvent for the quaternary salt formed during the implementation. Typical beneficial solvents

ι, to carry out the I implementation with moderate polarity are for example acetonitrile and dimethylacetamide. The reaction normally proceeds without the addition of Catalysts. It can also be carried out advantageously at temperatures from 20 ° C. to 30 ° C.

JM become, albeit higher and lower temperatures kmines are used. as long as that Reaction components remain in solution and they do not reach temperatures above their decomposition temperature be heated. The reaction products precipitate

. · ■> the solution and can be washed with solvents or by conventional known methods repeated recrystallization are cleaned.

The manufacture of a crfinding according to usable heterocyclic salt lal.it /. B. by

in the following reaction scheme:

(R '

CIL CII C R

R ¹

I'IL).

(O

where R 'is a radical of the formula (HR' isl and R as well as R. 7. and X have the meaning given.

Min typical. Ci'findungsgeinaß usable hot Basic salt, namely 3 (2 ronnylällivl) -2-mcthvlbcnzolhiazoliumbromid the formula:

S. IL), (II 151 O N IC C.

can be made, for example, as follows:

100 g of 2-methylbenzothiizoliumh \ drogenbromid and

48.7 g of acrolein were added with stirring at room temperature mixed in 150 ml of dimethyl chloride for 24 hours. A pale yellow one was distinguished crystalline precipitate, which is filtered off, washed thoroughly with acetonitrile and dried became. The yield was 100 g, corresponding to 31.3% of theory. The melting point of the compound Ing 233 to 236 C.

The perfect direct positive photograph! See silver halide emulsions moreover have those for direct-positive photographic silver halide emulsions known composition, d. H. they can, for example, from the usual gelatin silver Halide emulsions consist, the silver halide of which consists, for example, of silver bromide. Silver bromicliodide Π or silver chloride bromide. The use of sensitizing dyes is not required, although it may be advantageous to use such emulsions to expand their spectral sensitivity To add dyes. Sensitizing dye those in _ '<i Can advantageously be used for the spectral sensitization of the emulsions are, for example from US-PS 24 97 876, in particular column 2nd line 15th to column 4th line 20th known. the According to direct positive photographic> -) Silver halide emulsions can be made from undigested or digested silver halide emulsions, the digestion mixing without the addition of any Surface sensitization takes place.

An emulsion of this type is, for example, as j » "Burton's" emulsion known (see, for example, the book by Wall. "Photographic Emulsions". Publisher: The American Photo Publishers, Boston, USA, pages 52 and 53). Another type of direct positive emulsion, which are mostly latent images generating the part inside the silver halide grains Is emulsion, is known for example from US-PS 25 92 250.

Direct positive silver halide photographic emulsions. form latent images predominantly inside the silver halide grains produce ad may be prepared that silver halide grains are produced initially in one or more process steps, which consist at least partly of silver chloride. Then at least some of the grains are converted into silver bromide or silver bromide iodide, which is followed by ripening, preferably in the absence of ammonia, whereupon a part up to the total amount of the soluble salts present, as a rule! Sodium nitrate and / or potassium nitrate and sodium chloride and / or potassium chloride. After that, soluble salts are added to prepare the final emulsion, ζ. Β. of a soluble chloride, bromide or iodide. In this way a "built up" silver chlorobromide, bromide iodide or chloride bromide iodide direct positive emulsion is obtained.

Advantageous silver chlorobromide emulsions, the latent Images can also be generated predominantly in the interior of the silver halide grains produce in an advantageous manner that to a moving aqueous gelatin solution at the same time an aqueous silver nitrate solution and an aqueous solution of potassium chloride and potassium bromide are added as is known, for example, from Example 4 of US Pat. No. 2,996,382.

A typical silver halide photographic emulsion, that produces latent images predominantly inside the silver halide grains is one such emulsion, which behaves as follows:

If a portion of the applied emulsion is exposed for up to 1 second through a Lichlinlctisitälsskala and developed for 4 minutes at 20 ⁰ C in a conventional surface developer, that is, a developer that has a UiId only on the surface of the grains of an emulsion, the latent images for the most part generated and developed inside the silver halide grains and which has, for example, the following composition:

p-llydiOxyphynylglycine 10 g

Sodium carbonate (crystals) 100 g

made up to 1 liter with water

in this way a maximum density is obtained which is not greater is as' Λ the maximum density obtained when the same emulsion was exposed in the same way and for 3 minutes at 20 ° C. in a so-called internal grain roller which is an image inside the grains of an emulsion, the latent images predominantly generated inside the silver halide grains, developed, with the developer for example, it can have the following composition:

Hydroquinone 15 g monoinethyl-p-aminophenol-

stilfal 15 g

Sodium sulfite (anhydrous) 50 g

Potassium bromide 10 g

Sodium hydroxide 25 g

Sodium thiosulphate (crystals) 20 g

made up to 1 liter with water

Preferably, the maximum density obtained by development with the surface-type developer will not be greater than '/ io of the maximum Density obtained when the same emulsion is developed in the internal grain developer. Vice versa in terms of an emulsion, the majority of the latent images reside in the interior of the silver halide grains when developed in an internal grain developer to a maximum density, the at least 5 times, preferably at least that corresponds to 10 times the maximum density obtained when the emulsion is exposed in the same way and is developed in a surface-type developer.

The fogging agents to be used according to the invention are particularly suitable for direct positive emulsions of the type known, for example, from US Pat. Nos. 25 66 180 and 25 92 250. You become obvious adsorbed more firmly on the surfaces of the silver halide grains than those known from US Pat. No. 2,588,982 Hydrazine compounds. and therefore when using the fogging agents of the present invention lower concentrations of the same are required. The fact that so low concentrations of concealing agents are sufficient to achieve the desired concealment, constant advantageous sensitometric results can be obtained, in particular by the fact that fewer obscurants gets into the developer solutions.

The use of 0.2 to 1.4 g of fogging agent per mole has proven to be particularly advantageous Proven silver halide.

The direct positive photograph according to the invention!

can see silver halide refinements further The for direct positive phologriiphic silver halide emulsions typical /.usiit/e included. /. B. spectrally sensitizing dyes. Approval aid cl. optical brighteners, hardeners and agents ties. The usual known binders, in particular the bcl »s.inicn hydrophilic, water-permeable bandage Medium used, such as gelatin, colloidal albumin. Polyvinyl compounds. Cellulose derivatives and Aerylamide polymers. .tfld / was iillein or in combination with each other. If necessary, the binders, the / ur preparation of the Emulsions are used, also contain dispersed polymerized polyvinyl compounds, for example those known from U.S. Patents 3,142,568,3193,386,3062,672 and 3,220,844. to Such polymers include, for example, the polymers and latex copolymers used in WiiMti of alkyl acrylates, alkyl methacrylates, acrylic acid. Sulfoalkyl acrylates or sulfoalkyl methacrylates.

For the spectral sensitization of the invention (len Direct positive silver halide photographic emulsions may, for example, be those disclosed in U.S. Patents 25 26 632 and 25 03 776 known spectral sensitizers Dyes are used. The color snffc that can be used for spectral sensitization for example from cyanine, Mcrocyanine, complex trinuclear cyanine, complex trinuclear Mcrocyan -i-.Styryl and hemicyanine dyes exist.

The direct positive photographic Silver halide emulsions can also contain the customary, known nonionic, anionic and / or contain amphoteric coating auxiliaries, for example saponin, substituted by alkyl radicals Aryloxylalkylenäthylsulfonate, / .. B. of the type known from US-PS 26 00 831, Malcopimarate. /. B. of the type known from US Pat. No. 2,823,123, and also taurine derivatives. e.g. that of US Pat. No. 2,739,891 known type and alkylaminopropionate, /. B. of the type known from US-PS 31 33 816. Further known, advantageously usable coating auxiliaries are for example alkylphenoxypoly (hydroxyalkylene oxides), z. B. alkylphenoxypoly (glycidolc) with 5 to 12 glycidol units. for example those like them from the GB-PS 10 22 878 are known.

For the preparation of the direct positive photographic silver halide emulsions according to the invention in advantageously suitable optical brighteners are, for example, those with at least one heterocyclic 5- or 6-membered ring, for example derivatives of stilbene, slilbene triazole. Triazine stilbene, coumarins. Triazinylaminocoumarins, oxazoles, benzidines, benzimidazoles, Benzothiazole, benzoxazole, pyrazoline or naphthalenimide. Typical, for making a optical brighteners useful in a direct positive silver halide photographic emulsion according to the invention are known for example from US-PS 29 33 390 and 34 06 070.

The direct positive photographic Silver halide emulsions can be prepared with customary known hardeners or hardener combinations harden, e.g. B. with Aldehydhäriungsmiiteln, for example formaldehyde. Glutaraldehyde and maleic acid dialdehyde, also mucochloric acid, with iridine hardeners. Hardening agents consisting of derivatives of dioxane, vinyl sulfones, oxyl polysaccharides,

z. B. Oxysiärkc. oxidized plant / cMguminies. further inorganic hardening agents. /. B. Chromium / en.

For the production of direct positive photographic Recording materials can lead to the discovery ^ holographic silver halide emulsions can be applied to conventionally known substrates. There are, for example, various layers of this type from cellulose esters, for example cellulose acetate. Cellulose triacetate and Cclluloscacetaibutyrat, poly - \ - olefins such as polyethylene and polypropylene. Polycarbonates. Polyesters. /. B. polyethylene terephthalate, as well as of metals. /. B. zinc and aluminum or paper, which optionally has a layer of one May have poly \ olefin. /. B. one made of polyethylene or polypropylene.

The direct positive photographers of the invention Silver halide emulsions can be made from color pholographic as well as from black / white silver halide! Next, the direct positives according to the invention Color emulsions are particularly suitable for the production of such direct positive color recording materials. those generating using cyan, magenta and yellow dyes Color couplers are produced, the listed color couplers in contact with various There are silver halide emulsive layers that pick up light of a color that is practically complementary is the color of the dye produced with the aid of the color coupler. Color photographic recording materials of this type are known, for example, from US Pat. No. 3,227,550 and 3,227,552. To raise awareness of the silver halide, spectrally sensitizing dyes can be used in the customary manner will. In the case of a usual multilayer

t farbphoiographischcn up / cichnungsmaterials can rotaufzcichncndc emulsion layer, for example, 5- (p-Amylphenoxyben / olsulfonamido) -1-naphthol contain griinaufzeichnendc emulsion layer, for example, 2-CyanoacclyI-5- (p-scc.-aniylbcn / oylamino) couiiiaron and blauauf / Gauging emulsion layer, for example, N-amyl-p-bcn / oylacctaminobenzene sulfonate. If necessary, the color couplers can also be used in the developer solution, as is known, for example, from US Pat. No. 2,252,718 and 2,507,154. In this case, several exposures and color developing airs are required. After imagewise exposure, the photographic printing materials with direct-positive photographic silver halide emulsion layers can be developed on the silver halide in the usual way with the aid of a conventional surface developer solution with a relatively low solvent effect, positive photographic images being produced. The surface finishing agents used to develop the recording maicrialicn can advantageously contain image-intensifying compounds which increase the maximum density and lead to a reduction of [) """ . Such compounds can consist, for example, of Bcn / otriazoles, as they are known, for example, from US Pat. No. 2,497,917.

In the case of color-photographic recording materials Usual developing solutions with p-phenylenediamine color developer compounds can be used can be used, for example 4-amino-N-dialkylaniline, such as for example from the book by rvi e e s. »The Theory oithe Photographic Process ". 3rd edition (1966). pages 294 to 295 is known. By means of a color developer

Il

bond, one or more dye images can be produced, depending on the structure of the special color photographic recording medium. In the case of polychromatic color recording materials, blue-green layers normally become blue-green in the red, green, and blue-sensitive layers. generated purple or yellow dye images. The remaining silver is first converted into Sm- soluble silver salt and then removed in the usual way by treatment with a fixing agent, for example sodium thiosulfal. The following examples are intended to illustrate the invention in more detail.

Example I.

For comparison purposes, a recording material without a concealment agent (comparative label) was first produced by placing a gciatinc-silver brooch on the usual cellulose acetate film carrier. ims flnr U *** - ^^ 25 92 250 known type was applied. After the emulsion layer had been applied and dried, the recording material obtained was exposed to light in an Eastman IB type scanner. The recording material was then developed for 1 minute at 38 ° C in a developer solution of the following composition:

p-methylaminophynesulfal 2 g

Sodium sulfile (dehydrated) 90 g

Hydroquinone 8 g

Sodium carbonate (monohydrate) 52.5 g

Potassium bromide 5 g with water made up to 1 liter

The developed image was then stabilized by that it is placed in a fixer bath of 20 "C for 3 minutes with the composition given below wiwill ;:

Sodium thiosulfal 240 g sodium sulfil (dehydrated) 15 g

Acetic acid (28%) 48 ml boric acid. Crystals 7.5 "

Potassium aluminum sulfal 15 g

made up to 1 liter with water

A second recording material (recording material no. 2) was produced, exposed and wrapped in the same manner, with the exception, however, that a silver halide emulsion was used for the production of the drawing material, containing 200 mg of 3- (2-formylethyl) - per mole of silver halide as a compounding agent. 2-niethylbenzolhiaz.olium bromide contained.

A direct positive image was obtained.

The results obtained are summarized in the following table:

Relative Relative gamma /) "" "- \ Verl» "" "value

Comparative
Recording material No. 2

5.5

2.5

0.05 1.00

Example 2

First, a silver halide emulsion, the latent images for the most part in the interior of the

"> Silbcrhalogcnidkörncr produced, of the type as used for the preparation of Example 15 in U.S. Patent ?. layer I described 32 27 V) was prepared. In this case, however, was that of US-PS used in Example 15 32 27 552 l -Formyl-2-phenylhydrazide, the

in a concentration of 7 liig per 0.0929 tu- ' was used by 0.14 mg of 3- (2-formylethyl) -2-methylbcnzoihiazoliimbromid Replaced for every 0.0929 m layer bearing surface. The red sensitization obtained Pholographic recording material was then in

Π exposed to a sensitometer of the Easlman I Ii type, namely according to the example 15 of US-PS 32 27 552 described method. After exposure, the recording material was developed as follows:

jii A) 4 minutes development at 37.8'T in a developer solution of the following composition:

Benzyl alcohol 12 ml Nairium sulfite 1.5 g Potassium bromide 1.0 g 4-amino-N-ethyl-3-ynethyl-N- / J-methylsulfonamidoethylaniline 7.0 g Potassium carbonate (anhydrous) 55.0 g 5-nitrobenzimidaz.ol 5.0 ml topped up with water 1000 ml pH-Wcrl adjusted to 11.15 with sodium hydroxide represents.

B) Wash with 37.8 "C water for 15 seconds.

C ") 2 minutes bleach-fix at 37.8 ° C in one Image fixing solution of the composition given below for removing developed Silver crumbs and remaining silver salts:

Potassium ferricyanide 35 g

Sodium acetate 20 g

1.8 Dihydroxy-Jb-dilhiooclan 25 g
Glacial acetic acid 3 ml

made up to 1 liter with water

pll-Werl adjusted to 5.0 with acetic acid.

D) Wash for 2 minutes with 37.8 "C water.

E) Stabilize for 2 minutes at 37.8 "C" in a stabilizer bath with the following composition:

citric acid 20.0 g Nairium lciraborate 14.0 g Sodium hydroxide 0.22 g Formaldehyde (37% aqueous Solution) 1.0 ml topped up with water I liter

From the detailed results it can be seen that the varnish agent used is suitable for manufacture of direct positive emulsions.

After the development process and drying of the developed recording medium, a positive blue-green dye image with a maximum density (Ό ,,,., 0 of 1.94 and a minimum density (D ₁ ,,,,) of 0.25 was obtained. The image quality differed favorably on the quality of such images, which can be produced using previously known directional recording media, although the concentration of fogging agents is high compared to the known recording media

had been diminished. Furthermore, / ur Development of the recording process a developer be used with Vf rmindcrtcni pl I value, d. H. a Developer with a pH that is below pH of the developer. that applied when using a hydra / int type lubricant had to be (see. For example, the pH of the developer in Example 15 of US Pat. No. 3,227,552 of 12.0).

Example 3

There were six pairs of direct positive photographic images Drawing material produced, exposed and like the recording material No. 2 of the example

I developed, with the exception, however, duIi each one Recording material of a recording material pair res was developed at a pH of 12.15, which was obtained by adding sodium hydroxide to the developing solution. The rest of each Recording material from Aulzcichn./ngipaarc was developed at a pH of 10.5.

The recording drawings were produced using various concealment means. The type of sealing agent used, the density of the description and the resulting silky-clear results, such as maximum density (D _{m: n} ), minimum density (£>""") and contrast (} ') are summarized in the following table:

Pair Means of communication Ucschich- PlI = 10.5 '^ min ) ' pll = 12.15 '■' min Γ performance strengthc 0.10 1.0 0.09 1.3 in mg / mol silver 0.18 1.4 0.20 2.7 halide '■' nut \ I. 3- (2-formylethyl) -2-methyl- 450 0.55 0.08 4.0 1.22 0.07 2.9 bcnzothiazolium bromide 2 3- (2-Acctylätliyl) -2-benzyl- 450 0.94 0.08 2.0 3.27 0.10 U bcnzothiazolium bromide 3 3- (2-FOrmyla'thyl) -2-propyl- 1200 1.85 0.10 0.7 2.10 0.11 1.1 bcnzolhiazolium bromide 4th 5-chloro-3- (2-rormvläthyl) -2- 400 0.88 0.08 0.7 1.45 0.06 2.3 methylbcnzothiazoliutnbrotnid 5 3- (2-formylethyl) -5-methoxy-2- 400 0.40 1.30 methylbenzothiazolium bromide 6th 3- (2-acctylethyl) -2-propyl- 400 0.38 1.80

bcnzothiazolium bromide

From the scnsitometric data compiled in the table Results shows the advantageous effect of the closure agents according to the invention

tel. . .

Example 4

Further direct positive photographic recording materials were produced, exposed and developed as described in Example 3, with the exception, however, that the displacement ^{agents listed in the table below were used in concentrations of 425 mg per K 1} I / O of silver halide.

The results obtained are also summarized in the table below.

Concealers

Solvent for the
Wrapping agents

pH value of the D, "" _y developer

D _n

3- (2-acetylethyl) -2-benzylbenzothiazolium bromide 3- (2-acetylethyl) -2-benzylbenzothiazolium bromide 3- (2-Acetylethyne-2-benzylbenzoselenazolium bromide 3- (2-Acetylethyte) -2-benzylbenzoselenazolium bromide 3- (acetylethyl) -2-benzyl-5-phenyl-benzoxazolium bromide

3- (acetylethyl) -2-benzyl-5-phenylbenzoxazolium bromide

S - ^ - acetylethyl ^ -phenoxymethylbenzothiazolium bromide

S-CI-PropionyläthyO ^ -benzylbenzothiazoliumbromid

3- (2-AcetyIäthyI) -2-Ethylbenzothiazole bromide 3- (2-AcetyIäthyl) -2-ethylbenzothiazolium bromide

Acetonitrile 10.5 1.35 0.24 Methanol 12.1 3.28 0.2'i Methanol 10.5 0.60 0.15 Methanol 12.1 2.71 0.18 Methanol 10.5 0.23 0.05 Methanol 12.1 2.42 0.09 Acetonitrile 12.1 0.85 0.13 Methanol / 1% vinegar 12.1 2.33 0.35 acid solution (Γ: 1) Methanol 12y 1.59 0.09 Acetonitrile 12.1 2.52 0.07

The results obtained show the advantageous effectiveness of the fogging agents according to the invention.

Claims (1)

Patent claims: I. Photographic direct positive silver halide graphic emulsion, which produces latent images predominantly in the interior of the silver halide grains and contains a fogging agent, thereby marked that they are used as a means of concealment Contains 0.1 to 1.5 g per mole of silver halide of a compound of the following formulas: