DE1804468C - Direct positive silver halide photographic emulsion - Google Patents

Description

NO-

R ₁ N CC = CH-CC

CR R

R,

N - RCX

NO ₂

I = CH-C) -CH-CH) = TT = NR ₂

^{Rl N} \ / C

R ₃

where means

R is a hydrogen atom, an alkyl radical with 1 to 18 carbon atoms, an optionally substituted phenyl or Naphthyl radical or a heterocyclic radical, with the proviso that at least one of the radicals R is a hydrogen atom,

R ₁ and R 'each represent an optionally substituted alkyl radical each having 1 to 18 carbon atoms. an alkenyl radical or an optionally substituted phenyl or naphthyl radical,

R _{2 is} an optionally substituted alkyl radical with 1 to 18 carbon atoms, an alkenyl radical or an optionally substituted phenyl or naphthyl radical,

R _{3 is} an optionally substituted phenyl or naphthyl radical,

R _{4 is} a hydrogen or halogen atom or an alkyl or alkoxy radical each having 1 to 18 carbon atoms, an aryloxy radical or a nitro radical, X is an anion, η 1 or 2,

Z to complete a nitrobenzothiazok nitrobenzoxazole-, nitrobenzoselenazole-, imidazo [4,5 - b] -quinoxaline-. 3,3 - dialkyl - 3 H - pyrrolo- [2,3-b] pyridine-, 3,3-dialkyl-3 H-nitro-

indole. Thiazolo [4.5 - b] quinoline-. Nitroquinoline-. Nitrothiazoles Nitronaphthothiazole-. Nitrooxazok Nitronaphthoxazok Nitroselenazok Nitronaphthoselenazole- or nitropyridinrinees required atoms.

.1. Direct positive silver halide photographic emulsion according to claim 1, characterized in that they contain as cyanine 1. Γ-dimethyl-5.5'-dinitro-12 ^r diphenyl-3,3'-indulocarboc \ aninsalz.ein3'-ethyl-l-methyl-5.5 -dinitro - 2-phenyl-3-indolothiacarbooanine salt or a 1,3-diallyl-r-methyl-5'-nhro-2-phenylimidazo [4.5 - b] quino \ a! Ino-3 '- indolocrVesaninsal / eruha.lt.

3 Direct positive photographic silver halide emulsion according to Claim 1, characterized in that the silver halide grains are fogged.

4. Direct positive photographic silver halide emulsion according to claim 1, characterized in that the silver halide is in the form of silver halide grains obscured with a reducing agent and a gold compound is present.

5. Direct positive photographic silver halide emulsion according to Claims 1 to 3 characterized in that it contains fogged silver halide grains which are at least 95 percent by weight at least about micrometers in diameter does not deviate by more than 40 ° o from the mean grain diameter.

6. Direct positive photographic silver halide emulsion according to claims 1 to 6 thereby characterized in that the silver halide grains are sensitized by thiourea dioxide and potassium chloroaurate.

The invention relates to a direct positive photographic silver halide emulsion having a substance stops at an emulsion sensitizing cyanine dye with 2 nitrogen atoms containing heterocyclic rings, of which at least one 2-Arylindolrng, which are connected to one another via a methine residue.

It is known e.g. B. from the USA patents 930 694 and 3 314 796. to use photographic silver halide emulsions for the production of direct positive images, the indole cyanine dyes included as electron acceptors. The ones from the Both patents known silver halide emulsions also contain silver halide grains by means of a reducing agent and a Compound of a metal that is more electropositive than silver, have been veiled. An advantage of the like direct positive emulsions is that the areas of high lights of the preserved image are practically free of haze. Disadvantage of such However, emulsions are such that their sensitivity can be poorly suited for many photographic purposes leaves and especially not the desired sensitivity to radiation from green to red Have areas of the spectrum. Another disadvantage of such indole cyanine dyes

Silver halide emulsions is that the simultaneous use of color couplers in the emulsions to a reduction in the sensitivity / results of the emulsions after prolonged storage üer _a us the emulsions prepared on eichnungsmatenalicn. Also, emulsions containing color couplers have to be processed immediately after their production in order to avoid loss of sensitivity.

The object of the invention is therefore to provide a direct _IC . positive phutographic silver halide emulsion an _zl u'eb-n. do not ^m through a CyaninfarKioff r (leflcri-iber radiation from the green to the red zone ·;! the spectrum sufficiently aware Ut but _aU then ch if it contains a color coupler \ or · = the "application to a substrate in.... auüieschraoi / in a state without sensitivity ei lust can be stored for a longer period of time and also after application to a layer support maintains its sensitivity even when exposed to high temperatures and high humidity

The invention was based on the knowledge that the problem set can be achieved by using cyanine dyes for the production of the direct positive photographic silver halide emulsion, which are linked in the usual way from two nitrogen-containing, heterocyclic, by cmc methine chain rr.'to each other Rings exist, but in contrast to known cyanine dyes, one of the rings consists of a 2-arylindole ring substituted by a nitro radical and the second ring is a desensitizing ring.

The subject of the invention is thus a direct positive photographic silver halide emulsion containing a cyan dye sensitizing the emulsion with two nitrogen atoms containing heterocyclic rings, at least one of which is a 2-arylindole ring, which are linked by a methine radical, which is characterized . that it contains a 5-nitro-2-arylindole ring having cyanine dye of one of the following structural formulas:

where means

R is a hydrogen atom. an alkyl radical with 1 to! 8 carbon atoms, an optionally substituted phenyl or naphthyl radical or a heterocyclic radical, where that at least one of the radicals R is a hydrogen atom.

R _; and R 'each represent an optionally substituted alkyl radical each having 1 to IX carbon atoms, an alkenyl radical or an optionally substituted phenyl or naphthyl radical. R _: an optionally substituted alkyl radical with 1 to 18 carbon atoms, an alkenyl radical or an optionally substituted phenyl or naphtha radical.
R »is an optionally substituted phenyl or naphthyl radical.

R _{4 is} a hydrogen or halogen atom or an alkyl or alkoxy radical each having 1 to 18 carbon atoms, an aryloxy radical or a nitro radical. X is an anion, π 1 or 2.

Z to complete a nitrobenzothia / ol-, nitrobenzoxazole-. Nitrobenzoselenazole-. imidazo [4.5 - b] quinoxahn-. 3.3 - Dialkyl - 3 H - pyrrolo [2.3 - b] py ndin-. 3.3 - Dialkyl 3 H -nitroindole, thiazolo (4.3-b] ehinoline, nitroquinoline, nitrothiazoles, nitronaphthothiazole, nitrooxazole, nitronaphthoxazole, nitroselenazole, nitronaphthoselcnazole or nitropyridine rings.

NO ₂

R ₁ N

CC = CH -C = C

•NO

R ₃

or

R ₁ -N

= CH-C (= CH-CH) = fN-R ₂

The invention achieves that a direct positive photographic silver halide emulsion for Is available that

1. by excellent sensitivity to Radiation of the green to red areas of the spectrum with maximum sensitivities is characterized by usually 540 to 640 nm.

2. remains stable even after the addition of color couplers, so that it does not affect sensitivity

To avoid losses must be processed immediately after their production. and the

3. their sensitivity even after application to a substrate even when exposed to it elevated temperatures and extremely humid

conditions.

If R in the structural formulas given has the meaning of an alkyl radical, this preferably has 1 to 4 carbon atoms. In detail, R can thus be, for example, a methyl, ethyl, Propyl. Isopropyl. Butyl, cyclohexyl, or decyl carbon. If R has the meaning of an optionally substituted phenyl or naphthyl radical, then R is, for example, a phenyl, ToIyI, naphthyl or Be chlorophenyl radical. If R has the meaning of a heterocyclic radical, R can, for example, be Be thienyl radical. At least one of the radicals consists of a hydrogen atom.

If R ₁ and R ₂ are optionally substituted alkyl radicals, these can also consist, for example, of methyl, ethyl, propyl. Isopropyl, butyl, hexyl, cyclohexyl, decyl or dodecyl radicals. Suitable substituted alkyl

! 804 468

Rusts are hotly called llydroxyalkviresie./. B. -Ihdroxyäthyl- or ■ .-! ! vdrowhuiylresle. or Aiko \\ - alkylresle. /.B. .-Methowäthyl- or -Buu> \ vbutylreste. or carboxy alkyl oils. /. B. .'- carboxyethyl- or. —Carboxyhuty Iresie. or Su! foalk>! re-t-. z. B., - Sulfoälhyl- or ■ -Sulfobuiy Iresie. or saliatoalkyl radicals. 7. B. ..- Suifaioäthvl- or. .-Sulfai -hu:> I-reste. or \ eyloxvalkv lrcMe. /.B. i'-Acolov \ iith \ l-. ; -Acetoxypropyl- or ■.-BuivryloxyhutylreMe. or alkoxycarbonylalkyl radicals. z. B. ..'-Meihoxvcarbonyla'thy'i- or -Athoxscarbonylbutylreste. or aralkyl radicals. v. B. benzyl or phenethyl radicals. Preferably, R and R 'are short-chain. yegehenenl'alU suK-luted alkyl radicals with! up to 4 Kohienstofla'omen. If R ₁ and R have the meaning of Alkcr.ylriV.en. so the> e preferably have 3 to 4 carbon olalioms and consist, for example, of -MIyI-. 1-propylene or 2-butienyl residues. If R and R are optionally substituted phenyl or naphthyl radicals, these can for example consist of phenyl. ToIyI-. Naphthsl-. Methoxyphenyl or chlorophenyl radicals.

R ₁ can be one of the radicals indicated by _{R 1 and R 2.}

R; can for example be a phenyl. ToIyI- naphthyl- or be chlorophenyl radical.

R ₄ can, for example, be a methyl. Ethyl, propylene, isopropyl. Be butyl or decyl, or methoxy or butoxy. where the alkyl and alkoxy radicals are preferably short-chain radicals having 1 to 4 carbon atoms. If R _{4 has} the meaning of an aryloxy radical. so this can for example consist of an optionally substituted phenoxy or naphthoxy radical, z. B. from a tolyloxy radical. If R _{4 has} the meaning of a halogen atom, this can be, for example, a chlorine or bromine atom.

X can be, for example, a chloride, bromide. Iodide-. Sulfamate. Perchlorate p-toluenesulfonate or methylsulfate anion being. d. h is a common;, anion, such as e · ■; in commonly known cyanine dyes used for sensitizing photographic emulsions is open

Z stands for the completion of a nitrobenzothiazole ring required atoms, this ring can be, for example, a 5-nitrobenzothiazole, 6-N / robenzothiazole or 5-chloro-6-nitrobenzothiazole ring. Z stands for those required to complete a nitrobenzoxazole ring Atoine. so this can, for example, a 5-nitrobenzoxazole, 6-nitrobenzoxazole or 5-chloro-nitrobenzoxazole ring being. Typical nitrobenzoselenazole rings. Door that can stand Z are for example 5-nitrobenzoselenazole-, 6-nitrobenzoselenazole- <xJer S-chloro-ö-nitrobenzoselenazole rings. Z stands for to complete an imida7o [4,5-b] quinoxa! inring required atoms, this can be, for example, an imidazo [4,5-b] quinoxaline 1,3 - Dialkyltmidazo [4.5 - b] quinoxaltn ring. z. B. a 1,3 - diethylimidazo [4,5 - bjquinoxaline ring or a 6 - Cloro -1,3 - diethylimidazo [4,5 - b] quinoxaline ring. or a 1,3-cialkenylimidazo [4,5-b] quinoxaline ring, e.g. B. a 1,3-dially! Imidazo [4,5-b] quinoxaline ring or a 6,7-dichloro-1, J-diallylimidazo [4.5-b] quinoxaline ring. or a 1,3-diarylimidazo [4,5-b] quinoxaline ring. e.g. a 1,3-diphcyl-imidazo [4.5-b] quino-aline ring, or a 6-chloro-1,3-diphenylimidazo [4,5-b] quinoxa-see

_Λΐνι11 ζ for the necessary to complete a 3.3-Di- ■ _l lkvl- ^ Hp \ rrolo [2.3-b] pyridinnngcs, this can be, for example, em 3.3-Dim-thvMH-pyrrolo [2.3-b] pyridine or a , .- Diethvl-3 H-pvrrolo [2.3-b] pyridine ring. If Z stands for the atoms required to complete a 3.3-dialkvl-3H-rmroindolrinces, it can, for example, consist of a, 3-D.methy On.tro-, H-mdolnne. a ^ -Diethyl-vn.troO H-.ndol- or a r, -Dimethyl-6-nitro-3 H-indolnng exist.

Stand = Z for the completion of an N-.troquinolinrinBcs required atoms, then d. ^ er for example from a 5-Niirochinolin- or a h-Nitroehino'.mnng exist.

-Ms particularly advantageous cyanine dyes, h.hcn s, ch proved to be those of the formula Ii, in which Z du-, -ur Vervoilstandiiiunü of an imidazo [4.5-b] chim.vi; ir.-nnees represents required atoms.

Typical advantageous cyanine dye salts with sensitization maxima / wisch ^: 540 and 640 nm are for example:

l.r-dimethyl-5.5'-dinitro-2.2'-diphenyl-

3,3-indolocarbocyanine salts. l'-dibutyl-5.5-dinitro-2.2 -diphenyl-

λ V-indolocarbocyanine salts. 5-chloro-8-ethyl-IV-dimethyl-5-nitro-2.2-d! -

phony 1-3.3 indolocarbocyanine salts. U'-Dimethylo-nitroo'-phenoxy-IU'.g-tn-

phenyl-3.3-indolocarbocyanine salts, 8-cyclohexyl - ^ - methoxy-l.Γ-dimethyl-5'-nitro-

2.2 -diphenyl-3 3 -indolocarbocyanine salts. 5-Ethy 1-1.1 -dimethylo'-nitroO ^ '- diphenyl-

3.3 indolocarbocyanine salts. l.r-Dimethyl-5-nitro-2.2'-diphenyl-3.3'-indolo-

carbocyanine salts.
3-ethyl-l-methyl-5.6-dinitro-2-phpnyl-3-yne

dolothiacarbocyanine salts. 3-ethyl-l-methyl-5,6'-dinitro-2-phenyl-

3-indoloselenacarbocyanine salts, 3'-ethyl-1-methyl-5.6'-dinitro-2-phenyl-

3-indolooxacarbocyanine salts, 1.3-diethyl-r-methyl-5-nitro-2'-phenylimide

azo [4.5-b] quinoxalino-3'-indolocarbocyanine

salts.
r-methyl-5 -mtro- !. 2 .3-triphenyl-

imidazo [4,5-b] quinoxalino-3'-indolocarbo-

cyanine salts.
1.1.3.3 -Tetramethyl-5-nitro-2-phenyl-3-indolo-

pyrrolot2,3-b] pyridocarbocyanine salts and l, r-dimethyl-5-nitro-2-phenyl-3-indolo-

thiazolofÄS-bJquinolinocarbocyanine salts.

As already explained, the new cyanine dyes are extremely effective electron acceptors for direct-positive photographic silver halide mulrons. They can also be used excellently as desensitizers in emulsions, for example those described in US Pat. No. 3,250,618. The second ring connected to the 5-nitro-2-arylindole ring is, as already explained, a so-called desensitizing Rmg, ie a ring that is in the form of a symmetrical carbocyanine dye of a gelatin-silver chlorobromide emulsion with 40 mol percent chloride and 60 mol percent bromide in a concentration of 0.01 to 0.2 g of dye per mole of silver is added, by electron capture to an at least about 8O ⁰ OiBCn loss of blue sensitivity

7 8

Emulsion leads if these are sensitometrically exposed, with the exception that R ₄ does not

and for 3 minutes in a developer A is the fol-5-nitro radical, with an indole of the formula V in

The presence of a strong acid and in the absence of a strong acidic composition at room temperature

is wound: Trimethoxypropcn. According to a slightly modified one

_. ,. . 5 Appropriate chain substances can

Untwiclcier A tuated dyes by reaction of a compound

N-methyl-p-aminophenyl sulfate 2.0 g of formula type V, which is not sub-

Sodium sulfite (anhydrous) 90.0 g is substituted with a compound of formula type IV,

Hydroquinone 8.0 g in which R _{4 is} nitro-substituted. The Ver-

Sodium carbonate (monohydrate) 52.5 g to drive is done in the presence of a strong acid

Potassium bromide 5.0 g and in the absence of trimethoxypropene

Made up to 1.01 with water.

Dyes of the formula I with an R radical in the

Particularly advantageous desensitizing rings methine chain can be produced by reaction

are those which, after being converted into a sym- 15 of indoles of the formulas IV (R = nitro radical) and V in

metric carbocyanine dye and incorporating the presence of a strong acid and in its absence

into a silver halide emulsion of that described by trimethoxypropene.

Composition and testing in the described The asymmetrical cyanine dyes of the formula

Way to a practically complete desensitivity II can easily be prepared by reacting one

Protection of the test emulsion against blue radiation, 20 indoles of the formula V:

i.e., greater than about 90 to 95% loss of CHO

the sensitivity to blue, lead. .

The new symmetrical cyanine dyes of the ^.

Formula I. in which R _{4 is} a nitro radical can easily be j \ / ^

produced by reacting an indole of the fol- i $ O ₁ N-γ J r-R (Vl

Structural formula: V / \ / ³

H ^ V

C-R,

(UI)

35

wherein R, and R _{3 have} the meanings already given, with a heterocyclic compound of the formula

wherein R, and R _{3 have} the meanings already given, with a compound such as trimethoxypropene in the presence of a strong acid HX, for example a mineral acid or an organic sulfonic acid, e.g. B. hydrobromic acid, perchloric acid or p-toluenesulfonic acid, in which case it is expedient to work in an inert solvent medium, for example hot glacial acetic acid, and expediently about 2 moles of the indole are reacted with at least one mole of a compound such as trimethoxypropene and at least one mole of a strong acid . The crude dyes obtained in this process are removed by recirculation once or several times from suitable solvents, e.g. B. Purify methanol.

The asymmetrical cyanine dyes of the formula I. in which R _{4 is} a radical different from a 5-nitro radical. can be prepared by reacting an indole of the formula IV:

R ₂ -Nl = CH-CH) ^ f = C-CH ₃

in which n, R ₂ , X and Z have the meanings already given, in approximately equimolar proportions in an inert solvent, such as hot acetic anhydride.The crude dyes obtained can easily be purified by one or more recrystallizations from suitable solvents, such as methanol .

The compounds of formula III can be hole from indoles of the following formula

C-R,

(VII)

C = CH,

C (IVi ^to

α ^{C Rj} R

fc? where R, and R _{3 have} the meaning already given «

R have by reacting the same with sodium

nitrate in roughly equimolar amounts in an ai

wherein R. R '. R ₃ and R ₄ dkr already indicated reconcentrated sulfuric acid existing medium

9 10

jet temperatures of not above 10 ⁰ C produce. Trations of about 50 to 2000 mg, preferably about

The indole is preferably dissolved in sulfuric acid, 400 to 800 mg to be used per mole of silver halide

whereupon the solution is cooled and the sodium is turned over.

Litrat, dissolved in sulfuric acid, drop by drop under with obscured silver halide emulsions

Stir and add while cooling with an ice bath. ₅ meant here in particular those emulsions whose The nitrated indole can then be constituted by unique or silver halide grains such that at

repeated recrystallization from a suitable development of the emulsion a density of at least

Solvent, such as dimethylformamide, 0.5 is achieved if the emulsion is exposed without being exposed

be recrystallized. to be, for 5 minutes at 20 ⁰ C in a development

The formyl compounds of the formula V can be _I0 winder B developed with the following composition

from compounds of the formula IH, namely, if the emulsion corresponds to a silver

by reaction with a Vilsmeier reagent application of 50 to 500 mg per 0.09 m ² on one

(HCON (CH J, POCl) carrier applied is developed.

in approximately equimolar amounts of indole and _{: 5} developer B

Phosphoryl chloride. Preferably the phospho-N-methyl-p-aminophenol sulfate is 2.5 g

ryl chloride added to the dimethylformamide, whereupon sodium sulfite (anhydrous) 30.0 g

the resulting solution is cooled and the indole compound hydroquinone 2.5 g

is added, the mixture at about 40 C sodium metaborate 10.0 g

Stirred for 30 minutes or more. The Re- ₂₀ potassium bromide 0.5 g

action mix is then poured into ice water. Made up to 1.0 with water 1

whereupon the mixture obtained by adding a

aqueous alkali metal hydroxide solution, for example the new cyanine dyes can also

a sodium hydroxide solution, is neutralized, which advantageously direct-positive photographic

heated to the mix and see _is then cooled emulsions enforce their silver

is, whereupon the precipitate is filtered off grains of a water-insoluble silver salt

and can be washed with water. have existing core and an outer

Have in the manufacture of direct-positive photographi- case the water-shear from a veiled Si'oerhalogenidemulsionen this can unlö a "loan is silver salt which, without being exposed or more of the novel cyanine dyes added _Jo developed to silver. In this case will be. The silver halide emulsions, the dyes of the invention, can preferably be obscured from the outer surface in a conventional manner, when the silver halide grains are incorporated in such emulsions by the action of light or by means of ions. Such emulsions can be chemical fogging agents, e.g. B. stannous chloride. produced in various ways, for example after formaldehyde. The emulsions are Thiohamstoffdioxyd ₃₅ in which the L'the SA Patent 3,367,778 can advantageously also described in veiled processes.

by adding a reducing agent The shell of such grains can, for example, binding, ie a reducing agent, e.g. B. thiourine produced by the fact that on the core of the substance dioxide, and a compound of a metal. Grains a light-sensitive, water-insoluble S; i which is more electropositive than silver. is precipitated bersalz for example, by _40, which may be concealed. Addition of a gold salt, e.g. B. potassium chloroaurate. the haze can be removed by a bleaching process in accordance with British Patent 723 019. The cover should be

Typical reducing compounds or moderately consist of an intensity such that the reducing agent, the disguised for the preparation of advance of the development of the silver halide emulsion ver-can be used, ₄₅ used the developer is prevented at the core, for example, stannous salts. like stannous chloride. The silver salt shell is veiled so that it is using hydrazine. Sulfur compounds, such as thiourea, developer dioxide developing the usual surface images, phosphonium salts. how /. B. Tetra (hydroxy solutions to metallic silver are developed methyl) phosphonium chloride. Typical, to the manufac- turing crown. The silver salt of the sheath is severely fogged silver halide emulsions useful as lung veiled SITUATE ^ _0, that a density of at least 0.5 numeral compounds of metals that is more electropositive achieved when the emulsion after application to from silver are, for example, GoM. Rhodium. a carrier corresponding to a silver coating of platinum. Palladium and iridium compounds, which are present in a preferably in the form of soluble salts for 100 mg per 0.09 nr for 6 minutes at 20 C. Developer C of the additions specified below. B. potassium chloroaurate. Aurichloride. (NH ₄ I ₂ PdCl _6. «Composition is developed.

Reducing agents and metal bonds, ζ. B. .. _r Metal salt, can be used in different concentrations.

trations are added. N-methyl-p-aminophenobuHat 2.5 g is useful

SKh proved to be about 0.05 to ascorbic acid 10.0 g per viol of silver halide

40 mg reducing agent and about 0.5 to 15.0 mg ho potassium metaborate 35.Og

Add metal compound Particularly inexpensive Er- potassium bromide 1.0 g

Results are obtained when both re-filled with water to 1.01

reducing agent as well as metal binding in low pH-value 9.6

Concentrations are added. The concentration of the added to the emulsion Dyestuff or the dye-sensitization added to the emulsion up to the veil with sensitizers.:ie>-

substances can also be very different. As an expedient that oVr for chemical sensitization

It has proven to be a long time. the dyes in the concentrate core emulsion are described by higher light

11 Λ 12

Intensity can be achieved. While the cores are not a silver halide emulsion coated on a support

need to be sensitized to the veil, so that a maximum density of min

the shell is veiled. Be particularly advantageous at least 1.0 after 6 minutes of development

has a concealment by so-called Re- about 20 ⁰ C in a developer of the together

induction sensitizers, a noble metal salt, e.g. B. a 5 settlement B is achieved and comparison of the density de

Gold salt, and a so-called reduction sensitization developed silver halide emulsion layer mi

sator, "a sulfur sensitizer, high pH values of a corresponding emulsion layer, which 6 Mi

and low pAg silver halide precipitation conditions long at 20 "C in a developer of the composition

proven. Composition B was developed after it was 10 minu

The shell part of the grains can also be veiled _red for a long time at 20 ° C in a potassium cyanide bleach bath Will, e.g. B. by chemical means or by means of light, specified composition was bleached. Wi <

After the emulsion has been laid out on a support or already set out, the maximum density is the unge

Another layer has been applied. bleached emulsion layer by at least 30%. in

Before the shell made of a water-insoluble silver general by at least 60%. larger than the maxi

iclz is applied to the silver salt cores, the _T5 times density of the unbleached layer,

The so-called core emulsion was initially suitable for the production of the new photographic

Silver halides used in silver halide emulsions, treated physically or physically in a known manner

in centers to produce which precipitate or nid may be from any of the known more common

Precipitation of photolytic silver, d. H. photographic silver halides used for manuf

core centers producing latent images. The _Jo lung photographic silver halide emulsions ver

The necessary core centers can be used according to known methods and consist, for example, of silver

th generate, e.g. B. by chemical sensitization bromide, silver iodide. Silver chloride. Silver chlorobro

Like that of Antoine H a u t o t and Henri Sumbid. Silver bromoiodide and silver chlorobromoiodide V e η i e r in "Science et Industries Photographiques". Particularly good results are then obtained

ha. XXVIII. January 1957. pp. 1 to 23 and January _1957.2J when the silver halide grains have an average

Pp. 57 to 65. method described. Fine grain sizes that are less than 1 micron. Preference

Thematic awareness can be measured below about 0.5 microns, in three main ways. The silver halogens

achieve drive, d. H. By sensitizing grains, a regular structure can be created

4by a gold or other precious metal, but also by any known structure, e.g. B. cubic

Sulfur sensitization. z. B. by means of a labile ₃₀ or octahedral structure, ie for the case Compound containing sulfur atoms, or a spit! Structured !, as in the Belgian Paterü

fceduction awareness. z. B. Treatment of SiI writing 695 366 is described,

lerhalides with a strong reducing agent. Particularly useful silver halide emulsions

through which small spots appear in the grain of silver salt are also those in which the grains of silver halide

• Lethal silver be imported. 35 a uniform diameter frequency distribution

The new dyes are also particularly good. Such emulsions are described, for example, as highly sensitive electron acceptors in the Belgian patent Iche direct positive fogged silver halide emulsion 695 366.

• ions represent. As they are drawn, for example, in the Belgian Such emulsions, for example

Patent 695 3f ^{A can be} described. 40 as a result. that at least 95 percent by weight dei The fogged silver halide grains of such silver halide grains have a diameter Emulsions are such that a test of no more than 40%. preferably around nichl

rortion of the emulsions after application to a more than 30%. from the mean grain diameter

conventional photographic supports to achieve a soft. The mean grain diameter, i.e. H. by-

tiaximal density of at least about 1 to 6 average grain size, can easily be according to the usual

• After a long development at about 20 C in an unfamiliar method, such as for example

• ickler of the specified composition B a wise in the magazine "The Photographic Journal"

tiaximalc provides density by at least about 30% Bd. LXXIX. 1949, pp. 330 to 338

is greater than the maximum density of such an in tntspic- The fogged silver halide grains

A test specimen produced in a tender manner, after 6 minutes of direct-positive photographic emulsions

long at 20 C in a developer of the invention produce a density of at least

Settlement B is developed after the specimen is about 0.5. If you. without being exposed> u. For 5 minutes

For 10 minutes at 20 ° C in a bleach bath of my composition E developer at 20 ° C

the following composition: to be developed when the containing the grains «

_v , ■ ■. * n ss emulsion \ n with a layer thickness of 50 to approx

Kahumoamd *> mg ^ ^ ^ _{S |] hef pfo om m} , _{on nmn üh | ichcn F || m}

isessig ι V ιό carrier has been applied.

£ a nurnacetat .. ·· *? Particularly advantageous photographic silver halide

Na lurntwomKJ π ν mg genidcmulsionen are those whose silver halide Topped up with water on Il ^ _{mindcsXcns χ Moiproz £ nt from} silver bromide loaded

has been bleached. stands. Emulsions are particularly advantageous

The grains of such emulsions lose mc-silver bromoiodide emulsions. especially those that

at least about 25%. generally contain at least about less than 10 mole percent iodide.

40 ° .. of their veil if they can work for 10 minutes with The silver halide emulsions of the invention

20 C in a potassium cvanide-proof bath of the above-mentioned 65 on common known carriers ir S.hicht-

bleached composition. strengths of, for example, 50 to about 500 mg of silver

Such a loss of abrasion can be ^{applied per 0.09 m:} 1 surface area,

illustrate that the silver halide grains in I orm In the production of directo-positive photocranhi

shear silver halide emulsions become the dyes preferably incorporated into the washed, finished silver halide emulsion in which it is be distributed as evenly as possible. Process for incorporating dyes into photographic Silver halide emulsions are known and therefore do not need to be explained in detail at this point will. A common known method is to dissolve the dyes from solutions in suitable solvents to be incorporated into the F. emulsions. wol «ci for example Solvents such as methanol, isopropanol, pyridine, and water can be used.

The new dyes can in the usual Weiw incorporated into prepared silver halide emulsions, d. i.e., the emulsions can be used the customary known hydrophilic colloidal binders have been produced, as for example in U.S. Patent 3,039,873, and those made, for example, from naturally occurring substances such as gelatin, albumin. Agar Agar, Gum arabic or alginic acid or hydrophilic synthetic plastics, for example made of polyvinyl alcohol. Polyvinyl pyrrolidone. Cellulose ethers or partially hydrolyzed cellulose acetate.

The binder of the emulsions can also contain dispersed polymerized vinyl compounds, for example, as described in U.S. Patents 3,142,568.3,193,386,3 062,674 and 3,220,844 to be discribed. Such polymerized vinyl compounds consist of insoluble in water Polymers, for example polymers of alkyl acrylates and alkyl methacrylates. Acrylic acid, Sulfoalkyl acrylates and sulfoalkyl methacrylates.

As already stated, the new dyes can be incorporated in conventionally prepared emulsions are, preferably together with reducing compounds and noble metal compounds, the photosensitive silver halide being composed of any of the known silver halides, e.g. B. Silver chloride, silver bromide, silver chlorobromide. SiI-berbromoiodide or silver chlorobromoiodide. The use has proven to be particularly advantageous of the new dyes in direct positive fogged silver halide emulsions, in which the silver salt consists of a silver bromohalo ^ enide with more than 50 mole percent bromide.

The emulsions of the invention to which the new dyes have been added can be applied to conventional, known photographic film supports, that is to say at least sptebwetsc to film supports made of glass, fobea, e.g. B. from cellulose acetate. Cellulose acetate butyrates. Polyesters. z. B. polyethylene terephthalate paper, also on baryttertes paper, on paper coated with a polyolefin, for. B. a coated with polyethylene or polypropylene paper, which may have been subjected to electron irradiation to improve the adhesive strength of the emulsion before application of the emulsion.

In the manufacture of photographic recording materials using the novel silver halide photographic emulsions of the invention The silver halide emulsions can be used as well as other layers of a photographic recording material be hardened with the usual known hardening agents, for example aldehyde \ dhartero. z. B. formaldehyde and mucochloric acid. A / iridine hardeners. Hartem, which derivatives of dioxane * are, oxypolysaccharides, e.g. B. oxidized starch or oxidized vegetable gums. The emulsion layers The materials can also have customary additives, for example lubricants, stabilizers, the Sensitivity enhancing compounds, light absorbing dyes, plasticizers, and the like. Furthermore, the photographic emulsions of the invention can optionally contain additional socio-nal Contain sensitizing dyes and, as already stated, customary known color couplers or other. Color forming compounds.

Color couplers which are incorporated into the silver halide photographic emulsions of the invention can consist of the usual monomeric or polymeric color formers, e.g. pyrazolone color couplers as well as phenolic or naphtholic or heterocyclic, so-called open-chain Couplers with reactive methylene groups. The color couplers can be the direct positive

photographic silver halide emulsions according to the invention by conventionally known methods incorporated, for example, in U.S. Patents 2,322,027, 2,801,171 and 1,055,155 and 1 102 028 and 2 186 849.

i _S Furthermore, the silver halide emulsions can optionally contain incorporated developers, e.g. B. contain polyhydroxybenzenes, aminophenols or 3-pyrazolidones.

The following examples are intended to illustrate the invention

illustrate.

example 1

A. Preparation of U'-dimethyl-5,5'-dinitro-2.2-diphenyl-3.3-indolocarbocyanine p-toluenesulfonate

NO,

CH ₃ -N

CH = CH-CH <N-CH ₃

OSO ₂ CH-

1.26 g of 1-methyl-5-nitro-2-phenylindole and a 10% excess of p-toluenesulfonic acid monohydrate were dissolved in 10 ml of boiling acetic acid. Then 1.00 g of 1,3.3-Tnmethojiypropen were added with stirring. The mixture was then left seventh for several hours at room temperature, after which the precipitated dye was filtered off and washed with ether. After a single recrystallization from methanol, 0.42 g of pure dye, corresponding to 24% of theory, had a melting point of 205 to 206 ° C. (dec.).
B. The dye produced contains two sensitizing l-methyl-5-nitro-2-phenyündo'ir! «W. The dye has been tested for its usefulness as an electronic acceptor and a spectral sensitizer

1 804 488

in a veiled direct positive i-hotoL'raphic Silver halide emulsion tested.

First of all, a gelatin-silver bromide emulsion was used. the halide of which consisted of 2.5 mole percent iodide and the grains of which had an average grain size of about 0.2 microns, prepared by adding an aqueous solution of potassium iodide and potassium iodide and an aqueous solution of silver nitrate simultaneously within a period of 35 minutes "were added ¹ O C. The emulsion was then cooled to" a vigorously stirred aqueous gelatin solution to a temperature of noodled and washed in the usual way with cold W as> it. The emulsion was then initially obscured by a reducing agent and a gold, erbindune. 0.2 mg Vh! ·. ·. Urea dioxide per mole of silver were added to the emulsion, whereupon the emulsion was heated to 65 ° C. for 60 minutes. 40 mg of potassium chloroaurate per mole of silver were then added to the emulsion, or the emulsion was heated to 65 ° C. for another 60 minutes.

Then, per mol of silver OH, g of 1 Γ-dimethyl-. 5-dinitro-2.2 -diphen>I-3.3-; rsdo! .. carbocyanine-p-toluenesulfonal were added to the emulsion. The emulsion obtained was then applied to a conventional cellulose layer carrier in a layer thickness corresponding to 100 mg of silver and 400 mg of gelatin per 0.09 m ^: i γ j ^ er surface. applied.

[a sample of the recording material obtained; » was then exposed in a conventional senmometer using a tungsten lamp and then developed in a developer of the specified composition A for 6 minutes at room temperature.

The material was then fixed and washed and dried. The results obtained are summarized in Table I below.

The results obtained show that the dye of this example leads to a maximum density in the unexposed areas of 1.74 and a maximum density of 0.22 in the exposed areas, a maximum sensitivity at 630 nm and a relative sensitivity of 725, whereas a comparative material prepared and tested in a similar manner without a spectral sensitizing dye shows no reversal and has a relative sensitivity of less than 1.

These results show that the new dye is particularly useful as a spec; ial sensitizer for the preparation of direct positive photographic silver halide emulsions.

Excellent magenta dye images were obtained when H2.4.6-trichlorophenyl) -3.3 - (2 ".4" - di -1. - amylphenoxyacetamido) benzamido-5-pyrazolone was added as a color coupler to the emulsion prepared in the described manner the emulsion is applied in the usual way to a layer support, exposed by means of a tungsten lamp through Wratten filters No. 61 and 16 and according to the method described in US Pat. No. 3,046,129 in example (a). Column 27, lines 27 ff., The method described, with the exception that the black-and-white development described there was omitted, was developed. The color development could be reduced to 1 minute. It was carried out in absolute darkness until the completion of fixing.

B e ι ν ρ ι e 1 2

A. Preparation of 3-Ath \ l-l-meth \ l-5.6-dinitro-

2-phen \ 1-3 -indolo; hucarboo to in-

p-toluenesulfonate

STILL, N

CH -CH

NO-

I ..H,

OH <

OSCVC-H-

1.40 g of 3-formyl-1-methyl-1-nitroO-phenylindole. 1.98 g 3 - ethyl - 2 - methyl - 6 - mrobenzothiazolium p-to! Olsulfonate and 20 ml of acetic anhydride were refluxed for 1 hour. the The reaction mixture was then allowed to cool and slowly diluted with ether. The precipitated The dye was filtered off and washed with ether.

After two recrystallization from methanol were 0.92 g of dye, corresponding to 28% of theory, obtained with a melting point of 250 C (dec.). B. The obtained, a desensitizing I-methyl-5-nitro-2-phenylindole- and a desensitizing 3-ethyl-6-nitrobenzothiazoinng containing Dye was tested according to the procedure described in Example 1.

The results obtained are as follows later Table I compiled. From the data obtained it can be seen that densities \ on 1.78 and 0.03 for the non-exposed or exposed areas, one maximum sensitivity at 550 nm and a relative sensitivity of 11OG were achieved. From this It is found that the described dye is an excellent electron acceptor and an excellent one represents a spectral sensitizer for fogged direct positive emulsions.

Example 3

A. Preparation of 1.3-Dialvl-l -methyl-5-nitro-

2-phenvlimidazo [4.5-b] quinoxalino-

3'-indolocarbocyanine-p-t ~> luenesulfonate

NO,

CH ₁ -N

CH CH -

CJU

CH, CH = CH _;

N _v N _r ■ ^x
S ^ ^: N " ...
CH ₂ CH-CH ₂

OSO ₂ CH ₇

The dye was prepared and purified in the manner described in Example 2, with the exception, however, that 2.18 g of 1,3-diallyl-2-methyl-imidazo [4,5-b] quinoxalinium-p-toluenesulfonate instead of 3 - Ethyl 2 - methyl - 6 - nitrobenzothiazolium p-toluenesulfonate were used. The yield of purified dye was 0.65 g, corresponding to I9 ^o / o of theory The dye had a melting point 234-236 C (dec).

B The one described in the \ Wi-e Ί crgcstcllie. one desensir .senden 1-Methv! ö-nr.ro-Z-phenylindole- and one. de-T-ibiUiercnden; .. ^: -Diall> lmiuazo [4.5-b] chmo \ aiinrir.g containing dye was according to the one described in Example 1. Practically tested. The obtained Hr ^ ebni-c-md are listed in the skater in Table 1 below

From the preserved fruits I get ·! -I. djü at

Use of this dye densities vn L ^ vva ? Au ^ i 0.0 ^ Pur dieunexposierien b / v ,. exposed districts, κ- ι. .><-'- a maximum infinity at 545 nm and a

Tabe ^! ie ί

.iii.chkeii μ ·· π 11 5 « crrcithi wu

: ν ::: S ^ «*** ^ - ^that i ^{cr Farh}

^ '7' ^r ,;., .., ihiiur electronak / eptor ^ \\ ^cr \ '^ /! Sbilis.erung-mme

X > ren and

rmul

Dyes as IU ak Scns.blMerun ^

r.b: s.ch also.

rde. Made of fabric and a uurver-

ctroneniitie ¹ for:> i! ber- '• ij-tides

■ .. ■ Boi-r · - ■ rc M s .-> x- 725
1100 I. 0.70
0-5 ; 0.45 <\ Compare hs
attempt 0. (X)

The same favorable results as in Examples I. to 3, were obtained when in place of The dyes used here the following dyes were used:

1. Γ-Dimethyl-5.5 -py dolocarbotyaninsal / e. especially the corresponding chloride. Bromide. Iodide. Perchlorate, suliamate and p-toluenesulphonate;
II-Dibut> I-5.5 -dmitro-2.2'-cliphenyl-3J'-sndiv locarbocyanm salts. especially the chloride. Bromide. Iodide. Perchlorate, sulfamate and p-toluenesulfonate:

S-chloro-8-ethyl-1,1'-dimethyl-5-nitro-2,2-dipheny 1-3.3 -indolocarbocyanine salts. II - dimethyl-5-nitro-5-phenoxy-2.2'8-triphenyl-3.3-indolocarbocyaninsabe. S-Cydohexyl-S-methoxy-1.Γ -dimethyl-5-nitro-2.2-diphenyl-3.3'-indolocarbo; yanine salts. 5 - ethyl -1,1 '- dimethyl - 5 - ni: ro - 2,2' - diphenyl-3.3-indolocarbocyanine salts.
1.1-Dimethyl-5-nitro-2,2'-di]) henyl-3.3'-indolocarbocyanine salts.

3-ethyl-1-methyl-S.o'-dinitro-2-phenyl-3-indolothiacarbocyanine salts, in particular the chloride, bromide, iodide, perchlorate, sulfamate and p-toluenesulfonate,

3-ethyl-1-methyl-5.6-dinitΓo-2-phenyl-3-indoloselenacarbocyanine salts, especially the chloride. Bromide. Iodide. Perch orate, sulfamate and p-toluenesulfonate.

3-ethyl-1-methyl-5.6 «dinitroO-phenyl-J-indolooxacarbocyanine salts, especially the chloride, bromide. Iodide, perchlorate, s'jlfamate and p-toluenesulphonate,

l ^ -Diethyl-r-methyl-S'-niiro-Z'-phenylimidazo [4.S - b] quinoxalino - 3 '- indolocarbocyanine salts, especially the chloride. Bromide. iodide, perchlorate, sulfamate and p-toluenesulfonate, Γ - methyl - 5 '- nitro - 1 ^', 3 · triphenylimidazo- [4.5-b] quinoxalino - 3 '- indoocarbocyanine salts, in particular the chloride, bromide, iodide. Perchlorate. Sulfamate and p-toluene sulfonate, 1.1

ι no «. reversal

3 .3 -Ietramethyl-5-nitro -: - phen \ l-3-yn.i 4o- «> lof: .3-b] pyridocarbiKvaninsal / e and 1.1 - dimethyl - 5 - nitro - 2 - phenyl - 3 - ini'io thia / olo [4.5-quinolinocarbocyanine salt

3 °

The \ o-eil results from the following example.

which is obtained when using the new cyanine dyes when they are added to a photographic silver halide emulsion which has a '. <rb-

a matter-forming coupler and a colored coupler. As has already been explained, when the new dyes are used, the degree of loss of sensitization of photographic direct-positive silver halide emulsions on storage or on

like the emulsion diminished.

Example 4

The example compares the sensitivities of emulsions containing color couplers of the same composition, one of which was sensitized with the dye of Example 3 while two others Emulsions containing dyes without nitro residues. Half of the emulsion melts were applied to substrates immediately after their preparation, while the others Halves were kept at 40 ° C for 50 minutes prior to the coating operation. In detail was proceed as follows:

Various proportions of the same fogged direct positive silver bromoiodide emulsion, the was prepared by the method described in Example 1, were with the dye of the example 3 as well as the comparison dyes A and B.

A dispersion of a magenta dye was added to each portion of the emulsion forming color coupler of the constitution indicated in US Pat. No. 2,600,788, e.g. B.

1- (2'.4'.6'-Trichloropheny!) -3-benzamido-5-pyrazolone and a colored coupler as described in U.S. Patent 2,983,608, e.g. B. l- (2 ', 4', 6'-Trichlorophenyl) -3- {4 '- [fi (2' ". 4 '" - di-tert-amylphenoxy) -butyr-

amiü "] - anilino; -4- (4" "- meihoxyphen> li-azo-5-p \ ra / ')! on. added in tricresyl phosphate.

Half of each of the EmuUionsschmelzen was immediately after production on ι · ιπ>: π layer support applied while the remaining halves after storage for 50 minutes at 4 <ϊ C. corresponding substrate was applied.

The dried films were then exposed for 10 seconds in a spectrograph through a ^: - mm hr -.- iien slit and then developed in a p-methylaminophenol sulfate-hydroquinone developer for 6 minutes, fixed. washed and dried. The differences in the sensitivities obtained are shown in Table 1 'below. Table 11 shows the very coarse seriousness loss. the πιυ on keeping the ^Γ Γ! <! · "· η is achieved with the ertmdungsgemäß dye used, whereas in the case of the comparative emulsion concerning thtliche Hmpfindlichkeitsverluste entered

Table II

) Minutes

From example 3

A =! .3-diethyl-r-methyl-2'-ph <nylimidazo- [4.5-b] cL.noxaun-V-indolocarbocysninloid

B = 1.3-diethyI-1-methyl-2-pheny! -3-benz- [g] indoloimidazo [4.5-b] quinoxalinocarbocyanine iodide

less than 0.15 log E

0.45 to 0.60 log E

0.30 log E

The results obtained show that the stability of the silo halide emulsion according to the invention is at least a factor of 2 greater than the stability of the corresponding comparison emulsions with the dyes A and B.

When using other nitro-substituted 2-arylindole dyes corresponding favorable results have been obtained according to the invention. With others In other words: The new cyanine dyes used according to the invention act in accordance with the tendency of the color couplers contrary to the fact that direct positive silver halide emulsions containing color couplers contain sensitizing dyes lose their effect.

It has been shown that the inventively used Color couplers have the demonstrated effect of reducing the sensitizing effect of sensitizing dyes with the addition of customary color couplers in direct-positive photographic emulsions to counteract effectively! assets. The color couplers can consist of any known color couplers, such as those in the U.S. Patents 2,600,788 and 2,983,608.

Example 5

3,175 kg of a gelatin silver chloride emulsion from 100 g of silver nitrate, were heated to 40 "C. whereupon the pH of the emulsion was adjusted to a value of 7.8. The emulsion was then 8 ml added to a 40% formalin solution, whereupon the emulsion is heated to 40 ° C. for IU minutes was. Then the pH was adjusted to 6.Π, whereupon 0.125 g of the dye of Example 3 of Emulsion were added. The emulsion became

- then applied to a substrate in the usual way. When using the described recording material love direct positive images are more excellent (Juality preserved. Corresponding t'rge'nni-.se were obtained when instead of the color

i, - substance of example 3 the dyes of example 1 and 2 \ were used.

Example 6

, <To 4.0s kg of a üciaiine silver chloride emulsion. made from KX) g silver nitrate, O.OP g des Dye from B. Example 1 zuegebe.i. The emulsion was then put on a non-glossy paper backing applied and exposed to such flashes with white light

zo tet. that when the recording material was developed in a developer of the following composition, which was diluted per 1 part with 2 parts of water, a density of 1.2 was achieved.

N-meth> l-p-aminophenoisu! Fat 3.1 g

Sodium sulfite. of 45 g

Hydroquinone 12 g

Sodium carbonate, des 67.5 g

Potassium bromide 1.9 g

, o Topped up with water on 11

The light-obscured emulsion layer was then image-matched with a No. 15 cotton pad modulated light exposed in an image-correct manner, with a direct-positive image of excellent quality being obtained would. Similar results were obtained when the dyes of Examples 2 and 3 instead of the Dye of Example 1 were used.

The indoldenvates required for the production of the new cyanine dyes can be, for example, like produce as follows:

A. Preparation of I-methyl-5-nitro-2-phenylindole of the formula

CH ₃

10.35 g of 1-methyl-2-phenylindole were dissolved in 50 ml of 99% strength sulfuric acid. The solution was then cooled to 2 ° C. in an ice bath and a solution of 4.25 g sodium nitrate in 99% sulfuric acid (40 ml) was added dropwise over a period of 30 minutes with stirring and ice bath cooling. The temperature rose to a maximum of 8-1 ^° C. The mixture was then stirred for a further 5 minutes and then poured onto 350 g of ice with stirring. The solid precipitate which had separated out was isolated and washed with water. After a single re-6s it crystallized out Dimethylformamide, 9.6 g of the indole, corresponding to a 76% yield, were obtained. The compound had a melting point of 182 to 184 ° C.

B. Manufacture \ nn? -FV * rm \ l-l-meiln 1-5-πιΠ 2-phen \ lmdoi of the formula

CH,

2.5 ml of phosphorus were added / u 20 ml of dimethylformamide, whereupon the mixture was cooled to room temperature to g 1-Me; h; .i-Die! ösun "was then fermented in 2M ml of ice water, • so-on ^{; ς} ml of 5 η-sodium hydroxide solution were added The M ₁ SChUn ₁ * was then heated to boiling and ahkuhi-n eelas The precipitate was filtered out and washed with water The yield.: N cream-colored solid compound was fc. E. -; ri- -computing% ⁿ o of theory. The bchmei / nunk ·. I- : compound was 230 to 232 ° C

example
ι Vergieicnsbeispieii

E- were according to the invention% he \\ ended ι ■:
dyes mn from the LSA.-P.tentschntten 2>'' Γ

Hardly any temperature udkchuhu «uiui. c.-u. . · .- larnsione mn .iu.> <jv .. v.

5-nitro-2-phenylindole was then added, whereupon. _? IWW4und -. ^ 14 "96 known the mixture to 40 C for 45 minutes with stirring
was heated, whereby the precipitate dissolved

ciien. . , _

On the one hand, foil colored materials were used

Dye;

Struk.'L "formula

NO,

OSOX- H-

invention

B I

QH ₅

CH, CH = CH ₂

NO ₂

Ws.

C -CHf = CH

f ^ T = ^c

C ₂ H ₅ C! like B, but η =

R -

C - CH - = CH - n _n NR

R = C ₂ H ₅ - R = H- RHX-Br NO,

C ₂ H ₅ π = 1

like D, however

R = C ₂ H ₅ - R = H - R "= QH, - X = C1O ₄

C ₁ / \

QH,

> - CH = CH - C

/ A

CH,

NO ₃ USA.-Patent 2> ■ 2hl

U.S. Patent 2 2V-2M

U.S. Patent 2

USA. U.S. Patent 2,930

OSOX-H, I USA. Patent 3,314

The individual dyes were dissolved were then supplied at such Celluloseacetatschichtträgcr in solution bs applied in various äquirpolaren Konzenttationen that on a support surface of 0.0929 inside portions of a fogged direct positive silver SII 100 mg and 160 mg gelatin accounted for. The herberbromoiodide emulsion added. The emulsions skin recording materials were then in

23

in a fresh condition and after a one-week storage at 49 ⁰ C and a relative humidity of 50% exposed in a sensitometer of the Eastman 1b type, in a conventional hydroquinone methyl

p-aminophenol sulfa developer developed, fixed, washed and dried.

The following sensitometric results were obtained:

Dye (mg / mol Ag)

A (500)

B (332)

C (350)

D (363)

E (450)

F (408)

Relative sensitivity

100 39 14

78

105

49

Freshness » material Incubated material 1.20 Sensitive Wedge 1.10 maxima Om. O", 0 «. 0.76 (nm) 0.04 1.82 0.04 540 0.06 1.80 0.05 0.82 490 0.40 1.76 0.06 0.79 700 0.90 (weak) 0.41 1.82 0.26 640 0.07 1.72 0.06 670 0.06 1.78 0.05 550

The advantageous properties of the one used according to the invention emerge from the results obtained Cyanine dyes clearly.

Claims (1)

I 804 468 Patent claims: I. Direct positive photography before silver halide emulsion with a content of an emulsion sensitizing Cyunin dye contain two nitrogen atoms. heterocyclic rings, at least one of which is 2-aryl indole ring is. those via a methine residue with each other are connected, characterized that they have a 5-nitro-2-iirylindole ring containing C \ aninfarbstofT one of the contains the following structural formulas.