US2414491A - Photographic developer - Google Patents

Description

Patented Jan. 21, 1947 PHOTOGRAPHIC DEVELOPER Vsevolod Tulagin, General Aniline N. Y.,

Phlllipsburg, N. 1., assignor to & Film Corporation, New York, a corporation of Delaware No Drawing. Application January 27, 1945, Serial No. 574,973

16 Claims.

The present invention relates to photographic developers which may be used for the production of black and white images but are of special interest for the production of dyestuff images and to a process of producing said dyestufl images by color-forming development.

Para-phenylene diamines and substituted paraphenylene-diamines have been used extensively as photographic developers, particularly for fine grain work. It is considered that the fine grain obtained with these developers is attributable to some solvent action on silver halide and a comparatively low reduction potential. Despite the desirable properties which are possessed by pphenylenediamine and its N-alkyl substitution products, efforts are being continuously made to find other developers for black and white photographic work which show an improvement over the p-phenylenediamine and its N-alkyl substitution products, chiefly in regard to gradation and speed-utilization of the photographic negative emulsions.

One of the methods which is widely used for the production of color images involves the socalled color development method. This method was devised by Fischer and is described in his United States Patent 1,102.028. The basis of this process involves the reaction of the oxidation products of a primary amino developer, preferably a dialkylamino-aniline in the presence of a color former whereby dyestuff images are produced in situ with the silver image. Upon removing the silver'image by the use of a mild oxidizing agent such as a ferricyanide, followed by fixing with a thiosulfate bath, pure dyestufi. images are obtained. The color formers which are employed in this method may be generally classified as phenols, primary aromatic amines and compounds containing a reactive methylene group such as acetoacetanilides, pyrazolones and the like. By a proper selection of the color formers, there may be produced upon color development the desired subtractive colors in a threelayer photographic film, i. e., yellow, magenta and cyan. The dyestufis which are produced by this color-forming development method are of the type of azomethine and quinoneimine dyes.

I have now discovered that developers having properties superior to the conventionally employed p-phenylenediamine and its N-alkyl substitution products, are obtained by utilizing compounds which are aromatic amines, having a primary amino group and which contain on a ring carbon atom in o-position to the primary amino group a sulfonamido group, the primary amino group being activated by a substituent. preferably a substituted amino group in p-position thereto. These compounds when used as developers in the production of black-and-white images give a fine grain and greater contrast than can be obtained with the conventional p-phenylenediamines. They also permit better speed utilization of the photographic negative emulsion.

In the color development method. the density of the dyestuif image is proportional to the amount of silver image produced on development. My new developers because of their more energetic action, yield denser silver images of greater contrast than can be obtained with the usually employed p-dialkylamino-anilines, and this, in turn, means that the density and contrast of the color images are likewise enhanced. With the new developers it is possible to obtain sufliciently saturated or dense dye images from a normal negative emulsion having low or medium contrast, high speed and the finest possible grain. It is therefore unnecessary to build up excessive contrast to obtain sufficient dye density at the sacrifice of emulsion speed, gradation. latitude and grain. This property is of the greatest importance in the production of negatives by direct color development of an exposed film or plate where a well graded dye image must be obtained at often prevailing low levels of exposure.

However, probably the most important property of the new developers when used in the colorforming development method is their ability to yield as the ultimate dyestuff of the color image an azine dye rather than the usually obtained azo-methine and quinoneimine dyes. While the azo-methine and quinoneimine dyestuff images heretofore obtained are generally satisfactory, they possess the disadvantages of being unstable to light and to acids and alkalies. Consequently, there is the danger that such dyestuii images will fade appreciably after long use or if exposed to a sulfonamido group in o-position to said primary amino group.

A further object of this invention is to'produce azine dyestufi images by color-forming development.

A further object of, this invention is a process of producing dyestuff images by color developing an exposed silver halide emulsion with an aromatic amine containing a primary amino group activated by a substituent in p-position thereto and having a sulfonamido group in o-position to the primary amino group in the presence of a color former.

It is a further object of this invention to provide a process of producing azine dyestufi images by color development of an exposed silver halide with an aromatic amine containing a primary amino group and a sulfonamido group in position to the primary amino group in the presence of a color former.

It is a further object of this invention to produce color developers containing a color former and as the developer an aromatic amine having a primary amino group activated by a substituent in p-position thereto and having in o-position to said amino group a sulfonamido group.

It is a further object of this invention to color develop a photographic silver halide emulsion containing a color former fastto difiusion by means of a developer comprising an aromatic amine having a primary amino group activated by a substitutent in p-position thereto and having a sulfonamido group in o-position to the primary amino group.

Other and further important objects of the invention will become apparent as the description proceeds.

The developing agents which I contemplate may be generally characterized as aromatic amines containing a primary amino group and in o-position to' said amino group a sulfonamido group derived from an aliphatic or aromatic sulfonyl compound, the primary amino group being activated by a nitrogen atom in p-position to said amino group. The compounds may be purely aromatic and of the type of p-phenylenediamines or they may have a fused-on heterocyclic nucleus, in which case the activating N-atom in pposition to the primary amino group forms part of the heterocyclic ring system. In other words, the compounds always have at least one ring, aromatic in nature, to which the primary amino, sulfonamido and activating N-atom are linked. Compounds of this general character may be formulistically represented as follows:

and

NHSOaB in which R is an aliphatic radical such as methyl, ethyl, propyl, butyl, amyl, vinyl, allyl, cyclopentyl, cyclohexyl, chlorbutyl, sulfoethane and the like, or an aromatic radical such as phenyl, naphthyl, sulfophenyl, alkoxyphenyl, i. e., methoxyphenyl, ethoxyphenyl and the like, chlorphenyl, toluyl, anisyl and the like, R1 represents hydrogen or an aliphatic or aromatic radical as illustrated above, R3 represents hydrogen, sulfo, or an aliphatic or aromatic radical as above, Y represents --N, -NH, --Nalkyl such as Nmethyl, N--ethyl, --Npropyl and the like, and X represents the atoms necessary to complete a fiveor six-membered heterocyclic ring system such as a thiazole, an imidazole, a dihydropyridine, an oxazole, or the like.

Examples of compounds which fall within the general classes referred to hereinabove are the following:

3-phenylsu1ionamino-i-amino-diethylaniline N 2Hs)a 3-methylsuifonamino-4-amino-diethylaniline NH;I

NHS 02 o H;

N (C 2H5) 3-metliylsulfonamino-4-amino 6-methyl-diethyianiline N Hz) a 3-clilorbutylsulfonamino-i-amino-dimethylaniline N IHI) I S-dodccylsulfomminoA-amino-dlethylanilina NHSOgCH=CHa i-amino-3-vinyisullonamino-diethylaniline NH: I

NHBOICHI NHSOQ I CIR;

3-metboxy-3-phenylsulionamino-i-aminodiethylaniline 4 5 6 mrsomlri.-

fi-butylsulfonamino-5-aminobenzoxazole 5 6 7, rmsoicm 7-methylsulfonaminc-6-amino-l-N-methyl-dihydroquinazollne 2 1 NN-C 7H5 1-ethyl-5-amino-6-benzenesulionamino-iso-indazole H E--NC 2H5 l-ethyl-fiethylsulionamino-s-amino-benzimidazole The sulfonamido compounds of the present invention may be synthesized by various methods. For instance, the proper 3-alky1 or aryl-sulfonamino dialkyl-aniline may be nitrosated and the introso compound reduced to the required amine. Or such dialkylanilines may be nitrated and subsequently reduced. Furthermore, the prod 6 note can be obtained by the reduction of an appropriate azo dye, for example:

NHSOICHI RaN The reduction of the azo dyes may be performed by subjecting the dye to the action of hydrogen in the presence of a. hydrogenating catalyst such as platinum oxide, whereby the azo linkage is split and the amino group is formed.

It has been stated that the developers may be utilized toproduce azine dyes. It has been ascertained that in general such dyes are formed when the color formers are phenols, naphthols, anthrols and the like, aromatic amines and perimidines. In some instances when employing alkylated amino phenols as the color formers, for example, 3-diethylaminophenol, quinoneimine dyes rather than azine dyes appear to be formed. It is also observed that with the acetoacetanilides, dyestuffs are produced on color forming development which cannot be definitely identified as azine dyes. It is true that the dyestuffs obtained with these compounds have a higher stability to mineral acids than most quinoneimine dyes. However, unlike the azines, they are slowly bleached by mineral acids and by dichromate bleaches and hence it cannot be said with assurance that they are azines. i

The reaction by which the azine dyes are formed may be graphically represented by the following equation:

OH NH:

CONHCHQ NHSOaCHt It will be noted that there is first formed the quinoneimine dye the sameas when using the conventional p dialkylamino anilines. Subsequently, however, due to the presence of the: sulfonamido group, ring closure ensues, with split- 60 ting off of the sulfonyl group yielding the desired azine compound. The reaction depending upon the particular components involved may take place spontaneously so that the formation of the quinoneimine is not observable as an independent reaction. In other cases, however, the ring closure to the azine dye may take hours, or even days. The ring closure, however, can be facilitated or catalyzed by the utilization of acids such as hydrochloric, sulfuric, phosphoric and the like.

or by the use of alkalies such as sodium hydroxide,

potassium hydroxide, sodium carbonate and the like.

The developers herein described may be utilized to develop negative film, positive film, re-

versal film or paper prints. The developers may I using a freezing mixture of water and ice.

be employed along with the color formers in the developer or the color formers may be located in the emulsion. In the latter event, it is advisable to render the color formers fast to diffusion and this may be accomplished either by the in-' troduction of a substantive group or by the introduction of a molecular enlarging group such as a natural resin, a synthetic resin, a sterol, a carbohydrate, a terpene, or a long fatty chain. The lastvnamed method is preferred and good results have been obtained when using as such long chain, radicals such as decyl, dodecyl, stearyl, oleyl and the like. The means by which the color formers may be rendered fast to diffusion are described in U. S. P. 2,178,612, 2,179,228,

2,186,852 and the like. The color formers may be located in emulsionlayers of a multilayer film or a bi-pack, the color formers being selected so that subtractively colored dyestufi images are obtained in each of the layers.

When the color formers are located in the silver halide emulsion, the main ingredients of the color developer are the aromatic amine containing the sulfonamido group and an alkali. The

. color former of course is an essential ingredient whenall of the reaction components are in the developer. The alkali which is employed may be sodium bicarbonate, sodium carbonate and the like. The developer may also contain other ingredients such as an alkali metal bromide, i. e., potassium bromide, a sulfite, i. e., sodium metabisulfite, etc.

In carrying out the process while using the new developing agents, the emulsion after the formation therein of a latent silver image is developed with said developing agent in the presence of a color former whereupon the fihn is rinsed and subjected to the action of a stop bath. This bath usually comprises'a solution in water of. an organic acid such as acetic acid or an acid salt such as sodium bisulfite. Following this treatment, the silver is removed by a ferricyanide bleach, thoroughly washed and fixed in an acid-hardening typo. After washing free from hypo, the film is dried, whereupon a photographic element containing pure dyestufi image results.

The following examples will serve to further explain the present invention, but it is to be understood that the invention is not restricted thereto. The'parts are by weight, unless otherwise stated.

PREPARATION or rm: AROMATIC AMINES CONTAIN- me rm: Surrommno GROUP Example 1 Into a three-necked reactor equipped with a stirrer, a dropping funnel and a thermometer is introduced a solution of 55 parts of concentrated sulfuric acid in 2000 parts of water and to this solution are added 51 parts of 3-phenyl sulfonylamino diethylaniline hydrochloride. The mixture is stirred until said hydrochloride goes into solution, whereupon it is cooled to 3 C. 105 parts of sodium nitrite dissolved in 250 parts of water are added during a period of about minutes. The mixture is then stirred for an hour at 3 C. and filtered. The wet solid thus ob- .'tained is stirred for about one-half hour with stannous chloride dissolved in 163 parts of concentrated hydrochloric acid. The mixture so produced is stirred for 15 minutes and then placed in an ice bath for a few hours. The crystalline material which precipitates is dried and dissolved in a hot mixture of 200 parts of water and 16.6 parts of a solution of 100 parts of stan nous chloride in 233 parts of concentrated hydrochloric acid.

The mixture is decolorized by Nuchar, filtered and the filtrate is treated with a solution of 100 parts of stannous chloride in 233 parts of concentrated hydrochloric acid. This mixture is placed in an ice chamber for three hours, whereupon the white crystalline 3-phenyl sulfonamino-4-amino-diethylaniline stannochloride precipitates. It is washed with a little concentrated hydrochloric acid and dried. The yield is 63 parts. For convenience, this product will hereinafter be referred to as developing agent I.

Example 2 for 1 hour and then treated with 12 parts of anhydrous pyridine and stirred over night at room temperature.

The thick slurry thus obtained is filtered and the precipitate is twice washed with 44 parts of anhydrous benzene. The resinous solid which results is boiled for 20 minutes with 118 parts of isopropyl alcohol and the mixture is then placed in the ice chest for several hours. The crystalline 3-methyl sulfonamino diethylaniline hydrochloride so obtained is isolated by filtration, washed with 118 parts of isopropyl alcohol and dried. There are obtained 84 parts of colorless crystals, representing a yield of 82 per cent.

28 parts of the 3-methyl sulfonamino diethylaniline hydrochloride are dissolved in 1000 parts of water and 47 parts of concentrated hydrochloric acid and the solution cooled to 5 C. 7 parts of sodium nitrite in 15 parts of water are added dropwise to the cooled solution with agitation. After about 1 hour and a half, the suspension is filtered and the 4-nitroso-3-methyl.

sulfonamino diethylaniline hydrochloride so obtained is dried in a vacuum desiccator. There are obtained 29 parts of the product, representing a yield of 93.5 per cent.

A mixture of parts of absolute alcohol, 30 parts of distilled water, 31 parts of i-nitroso-3- methyl-sulfonamino diethylaniline hydrochloride and .2 to .3 part of platinum oxide is subjected to the action of hydrogen at 60 pounds gauge pressure. The reactor is then carefully opened and 13 parts of concentrated hydrochloric acid introduced. The air in the reactor is replaced by hydrogen and the contents thoroughly mixed. The suspension is filtered and the platinum is removed by washing with a solution of 12 parts of concentrated hydrochloric acid in 50 parts of water and the mixture filtered. The two filtrates are combined and evaporated to dryness at a pressure of 3 mm. at a temperature of 98 C. The residue is dissolved in 79 parts of absolute alcohol and the solution placed in an ice chest over night. There is thus obtained crystallins 3-methyl sulfonamino 4 amino-diethylaniline hydrochloride, which is washed to a light yellow color with absolute alcohol. 25.5 parts of the product are obtained, representing a yield of 79.5 per cent. For convenience, this product hereinafter will be referred to as developing agent IE.

Example 3 38.2 parts of methyl sulfonyl chloride are added dropwise to a solution of 50 parts of 2-methyl- -amino-dimethylaniline and a small amount of pyridine in 264 parts of anhydrous benzene while agitating the solution. The addition takes about 20 minutes. After standing at room temperature for 1 /2 hours, the mixture is refluxed on a steam bath for minutes and cooled with ice. The resulting crystalline solid is isolated by filtration, dried and heated to boiling with 158 parts of absolute alcohol. The mixture is cooled, whereupon 2-methyl 5 methylsulfonamino-dimethy1 aniline hydrochloride precipitates. .The precipitate is isolated by filtration and dried. 62.9 parts of the product are obtained, which represents a yield of 81.8 per cent. The product when analyzed showed:

Calculated C: 45 59 45.34 H: 6.46---- 6.47 Cl: 13 2 13.38

sodium hydroxide solution and allowed to stand I for two days. The solution is then saturated with salt and made strongly acid with hydrochloric acid. The dye, which crystallized in long needles, was collected, washed with a little water and dried. 24.1 parts of the dye are obtained, which represents a yield of 65.7 per cent of the pure Z-methyl sulfonamino-4-dimethylamino-Eimethyl azobenzene-4'-sulfonic acid.

14.5 parts of sodium hydrosulfite are added to I a mixture of 12 parts of the above azo dye, 3.3 parts of anhydrous sodium acetate and 100 parts of water. The solution is then extracted five times with 16 parts of carbon tetrachloride and neutralized with sodium carbonate. The suspension thus obtained is extracted three times with 32 parts of carbon tetrachloride. The aqueous phase is discarded. The combined organic'extracts are extracted successively with 78.75 parts, 26.25 parts and 15.75 parts of 5% hydrochloric acid solution in water. These acid solutions are evaporated to dryness at 98 C. under 3 mm. pressure and the residue is recrystallized from 32 parts of absolute alcohol. 2parts of 2-methyl-4-amino- 5-methyl sulfonamino-dimethylaniline dihydrochloride, representing a yield of 24.5 per cent is thus obtained. This product is hereinafter to be referred to as developing agent III.

Example 4 A solution of 20 parts of l-ethyl-B-nitro iso 'indazole (prepared by the method of Witt-Noeltig and Grandmaugen, Ber., 23, 3640) in 200 parts of ethyl alcohol is treated with .2-.3 part of platinum oxide catalyst and reduced with hydrogen at 60 pounds gauge pressure until no more hydrogen is taken up.

The suspension is filtered and evaporated to dryness. at reduced pressure. The residue is treated with 15 parts of anhydrous pyridine and again evaporated to dryness at reduced pressure. The residue is now dissolved in parts of pyridine.

To the resulting solution, is added dropwise, with cooling and agitation, a mixture of 19.3 parts of benzenesulfonyl chloride and 45 parts of benzene. The temperature ofthe mixture is maintained at 15 C. during the addition. After stirring for 16 hours, the reaction mixture is evaporated to dryness at reduced pressure.

The residue is taken up in 50 parts of ethyl alcohol and added to 300 parts of 6 N hydrochloric acid. The resulting solution is warmed to 50-60 C., decolorized, cooled with ice, and neutralized with concentrated ammonium hydroxide.

The resulting suspension is held in an ice bath until the precipitate solidifies and is then filtered. The solid so obtained is dissolved in 50 parts of hot ethyl alcohol. The resulting solution is treated with hot water to incipient cloudiness, decolorized and cooled. The crystalline material so obtained is used without further Durification. Yield-20 parts by weight.

To a solution of 15 parts of the above l-ethyl- G-benzenesulfonamino isoindazole in 100' parts of glacial acetic acid and 20 parts of acetic anhydride is added dropwise and with agitation a solution of 3.2 parts of fuming nitric acid in 40 parts of glacial acetic acid. The temperature of the mixture is maintained at 6070 C. during the addition and then for 25 minutes longer. The mixture is, finally, cooled and. added to 200 parts of ice-water.

The crystalline solid so obtained is collected by filtration, washed with water and dissolved in a hot solution of 20 parts of sodium bicarbonate in 200 parts of water. The resulting red solution is decolorized and acidified with acetic acid. The precipitated yellow solid is collected by filtration and washed with water.

Said yellow solid is dissolved in 40 parts of boiling acetic acid and poured into 200 parts of boiling 6N sulfuric acid. The precipitated by-product of l-ethyl 6 benzenesulfoamino-7-nitroisoindazole is collected by filtering the hot solution. The filtrate on cooling deposited long white needles of l-ethyl-6-benzenesulfonamino-5-nitro isoindazole sulphate.

The isoindazole sulphate obtained above is dissolved in an excess of dilute sodium hydroxide and the free 1-ethyl-G-benzenesulfonamino-5- nitroisoindazole is precipitated by saturating the resulting solution with carbon dioxide, The substance is further purified by crystallization from acetic acid. Yield-7 parts (40% theory). The product when analyzed showed: Found, N: 15.98; calculated, N: 16.18. 1 part of the above nitroisoindazole is treated with 10 parts of 3N sodium PREPARATION OF DEVELOPER SOLUTIONS Example 5 Part I: I Parts Developing agent I 7.5 Water 300 11 After the developing agent;has been completely dissolved, add

Nuchar (a decolorizing carbon black) 2 The suspension is saturated with hydrogen sulfide gas. 5 parts of Nuchar are added, and the suspension filtered. The filtrate is boiled until it is free of hydrogen sulfide, whereupon 5 parts of sodium metabisulfite are added. If this solution is to be stored, it should be kept in a wellstoppered bottle.

Part II: Parts Water 800 Sodium bicarbonate 30 Potassium bromide .5

When the developer is to be used, one volume of part I is added to four volumes of part II, the solution boiled for a few minutes, and cooled to 18 0.

Example 6 Part I is the same as part I of Example 5.

Part II: Parts Water 800 Sodium carbonate (monohydrate) 60 Potassium bromide .6

When this developer. is to be used, one volume of part I is added to four volumes of part II.

Example 7 Part I: Parts Water 250 Developing agent II 3.5 Sodium metabisulfite 3.5

Part II:

The same as part II of Example 5.

When this developer is to be used, one volume of part I is added to four volumes of part II, the solution boiled for a few minutes and cooled to 18 C.

Example 8 Part Us the same as part I of Example '7. Part II is the same as part II of Example 6.

When the developer is to be used, 1 volume of part I is added to 4 volumes of part II.

Example 9 Part I: Parts Water I 250 Developing agent III 5 Sodium metabisulfite 5 Part 11:

Same as part II of Example 6.

When this developer is to be used, 1 volume of part I is added to 4 volumes of part II.

Example Part I: Parts Developing agent IV 7.5 Water 300 After the developing agent has been completely dissolved, acid Parts 2 The suspension is saturated with hydrogen sulfide gas. Five parts of Nuchar are added and the suspension filtered. The filtrate is boiled until Nuchar Parts it is free 01' hydrogen sulfide, whereupon five parts of sodium meta-bisulfite are added;

Part II: Parts Water 800 Sodium bicarbonate 30 Potassium bromide .5

When the developer is to be used, one volume of part I is added to four. volumes of part II, the resulting solution boiled for a few minutes and cooled to 18 C.

I Pnocmssmo or Emslous wrrn Dnvnnorns Example 11 5 parts of 1-hydroxy-2-naphthanilide are added to the developer of Example 5. A photographic silver bromide emulsion is exposed and subjected to the action of said developer for a period of 15 minutes. The film is rinsed and treated with a stop bath containing 1000 parts of water and.

7.34 parts of glacial acetic acid. The emulsion is then treated with a bleach oi the following composition Parts Water 1000, Potassium ferricyanide Disodium phosphate 4 Monopotassium phosphate 6 The film is thoroughly washed and is then fixed in an acid hardening hypo bath. After removal of the hypo by washing and drying of the film, a red magenta azine dyestufi image is obtained.

Example 12 10 parts of N-methyl-1-hydroxy-2-naphthanilide are added to the developer of Example '6. An exposed silver bromide emulsion is developed in the developer for a period of 10-20 minutes and then processed as in Example 11. A red magenta azine dyestufi image is thus obtained.

Example 13 Example 14 5 parts of 1.5-dihydroxynaphthalene are added to the developer of Example 8. An exposed silver halide emulsion developed in said developer and further processed as in Example 11 yields a red magenta azine dyestufi image.

Example 15 10 parts of 2-methyl perimidine are added to the developer of Example 5. An exposed silver halide emulsion is developed in the resulting developer and processed as in Example 11. There is thus obtained a film having a blue azine dyestufi image.

Example 16 10 parts of 1.5-dihydroxynaphthalene are added to the developer of ,Example 9. An exposed silver halide emulsion is developed in this developer and then processed as in Example 11. A

13 red dyestufi? image of an azine dye is thus obtained.

Example 17 4 parts or octadecyl-I-hydroxy-Z-naphthoylamide are dissolved in 5 cc. of sodium hydroxide solution of 20 per cent strength and about 50 cc. of methanol and the resulting solution is added to 1000 parts of a photographic silver halide emulsion. The resulting emulsion is coated on-film, exposed and developed with the developer of Example 5. The film isgthen further processed as in Example 11. There is thus obtained a red magenta azine dyestuff image.

Example 18 1 kilo of a silver bromide emulsion is mixed with an aqueous solution of 15 parts oi. the sodium salt of 4"-stearylamino benzoyl-3-aminobenzenesulfonyl-lamino 8 hydroxynaphthalene- 3.6-disulfonic acid. The emulsion is coated on a support to form a photographic silver halide emulsion layer.

The emulsion is exposed and developed with the developer of Example 5. After development, the film is processed as in Example 11. There is thus obtained a red magenta azine dyestuif image.

Example 19 bleaches; These azine dyes because of their stability have marked advantages over the usual azomethine and quinoneimine dyes.

Modifications of the invention will occur to persons skilled in the art and I therefore do not intend to be limited in the patent granted except as necessitated by the prior art and the appended claims.

I claim:

1. A photographic developer comprising an aqueous alkaline solution of a compound selected from the class consisting of those of the formulae:

in which R is selected from the class consisting of aliphatic and aromatic radicals, R1 is selected from the class consisting of hydrogen, aliphatic and aromatic radicals, R3 is selected from the class consisting of hydrogen, sulfo, aliphatic and aromatic radicals, Y is selected from the class consisting of -N, -NH, -N-alkyl, and X -repre- Color former Developer Color 1-hydroxy-2-naphthanilide Ex. 7 Red magenta.- A N-methyl-l-hydroxy-2-naphfhanil dp Ex. R A N-mlgthyl-l-hydroxy-2'naphthan1l1de-4sulfonic acidi O 1.5-dihydroxynaghthnlep A l-hydroxy-Q-nap thanllicle A fl-[ammo-2-(7-hydroxynaphthyl)] crotonic acid 5. i

Do A 8-methanesu]fonaniino-l-naphthol i A B-benzeuesullonammo;l-naphthol 5 A Benzenesulfonyl H acid 5 Reddlsh blue A 4-hydroxybenzcarhazole (1,2)-2-su1iqmc i Ex. 6 dn A 1,8-naphthylene Ex. 6 .do A 2,5-dihydroxydiphenyl Ex. 5 Magenta A 3-allyl rhodamne Ex. 6 do S 3-diethylaminophenol Ex. 5 Blue. 8, Acetoacet-aniiide. Ex. 6 Yellow Do Ex. R dn S @Methoxyanefnqoofanilide Ex, 6 rin S 8-acetamino-l-naphtl1ol. Ex. 5 lue. S Phenyl J acid... Ex. 6 Violet A l-anthrylglyoine Ex, 5 A Diphen l E-acid Ex. 5 Green S 2-(2-car oxyphenyl)-per1m1dme Ex. 5 Greenish blue... A 2-(3'-nitro-2'-oarboxyphenyl)-perlm1dine Ex. 5 Magenta A 2-perimidylacrylic acid Ex. 5 Blue. A Phenol Ex. 9 Yellow S -Crecnl Ex, 9 "Red A A=azine dye.

Q=quinoneimine or azomethine.

S=uneertaindyes in this class shoulv1 a high stability to mineral acids but are slowly bleached by them.

The same is true with dichromate blea The azine dyestufi images which are produced as above are, as stated, stable to mineral acids and strong alkalies. Furthermore, they are not afiected by sulfurous acid nor by dilute acid disents the atoms necessary to complete. a ring system selected from the class consisting of 5: and S-membered heterocyclic ring systems.

2. A color developer comprising an alkaline chromates such as are employed as dichromate solution of a color former and a compound selected fromthe class consisting of those of the formulae: 1'

in which R is selected from the class consisting of aliphatic and aromatic radicals, R1 is selected from the class consisting of hydrogen, aliphatic and aromatic radicals, R3 is selected from the class consisting 'of hydrogen, sulfo, aliphatic and aromatic radicals, Y is selected from the class consisting of -N, -NH, -N-alky1, and X represents the atoms necessary to complete a ring system selected from the class consisting of and B-membered heterocyclic ring systems.

3. A color developer as defined in claim 2 in which there is present an alkali metal sulfite.

4.,A photographic developer comprising an alkaline solution of 3-phenyl sulfamino-l-aminodiethylaniline.

5. A photographic developer comprising an alkaline solution of 3-methyl sulfonamino-4-amino diethylaniline. i

6. A photographic developer comprising an alkaline solution of 2-methyl-4-amino-5-methylsulfonamino-dimethylaniline.

'l. A color developer comprising an alkaline solution of 1-hydroxy-2-naphthanilide and 3- phenylsulfonaminol-amino-diethyl-aniline.

8. A color developer comprising an alkaline solution of 1.5-dihydroxynaphthalene and 3- methyl-sulfonamino-4-amino-diethylaniline.

9. A color developer comprising an aqueous a1- kaline solution of 2-methyl perimidine and 3- phenyl-sulfonamino-4-amino-diethylaniline.

10. The process of producing photographic color images which comprises subjecting an exposed silver halide emulsion in the presence of a color former to the action of a developer containing as the developing agent a compound selected from the class consisting of those of the following formulae:

5 v inwhich R is selected from the class consisting 01' aliphaticand aromatic radicals, R1 is selected from the class consisting of hydrogen, aliphatic and aromatic radicals, R3 ,is selected from the class consisting of hydrogen, sulfo, aliphaticand aromatic radicals, Y is selected from the class consisting of -N, '-NH, -N-all yl, and X represents the atoms necessary to complete a ring system selected from the class consistingo! 5- and 6- membered heterocyclic ring systems.

11. The process of producing azine photographic dyestufl images which. comprises subjecting an exposed silver halide emulsion in the presence of a color former selected from the class consisting of phenols, aromatic amines and perimidines, to the action of a developer containing as the developing agent a compound selected from the class consisting of those of the following formulae:

in which R is selected from the class consisting of aliphatic and aromatic radicals, R1 is selected from the class consisting of hydrogen, aliphatic and aromatic radicals, R: is selected from the class consisting of hydrogen, sulfo, aliphatic and aromatic radicals, Y is selected from the class consisting of -N, -NH, -N-alkyl, and X represents the atoms necessary to complete a ring system selected from the class consisting of 5- and 6- membered heterocyclic ring systems.

12. The process of producing an azine dyestuil' image which comprises subjecting an exposed silver halide emulsion to the action of a color developer containing l-hydroxy-Z-naphthanilide as the color former and 3-phenyl sulfonamino-4- amino-diethylaniline as the developing agent.

13. The process of producing azine dyestufl images which comprises subjecting an exposed silver halide emulsion to the action of a developer containing 2-methyl perimidine as the color former and 3 phenyl sulfonamino-4-amino-diethyl-. aniline as the developing agent.

14. The process of producing azine dyestufl images in a photographic silver halide emulsion which comprises exposing the emulsion and developing the same in a color developer containing 1.5-dihydroxynaphthalene as'the color former and B-methyl sulfonamino-l-amino-diethylaniline as the developing agent.-

15. The composition as defined in claim' 1 wherein there is present an alkali metal sulflte.

16. The process as defined in claim 11 wherein there is present an'alkali metal sulflte.

VSEVOLOD TULAGIN'.