US3028237A

US3028237A - Masking of cyan images in color photography

Info

Publication number: US3028237A
Application number: US727043A
Authority: US
Inventors: Loffler Karl
Original assignee: Agfa AG
Current assignee: Agfa Gevaert NV
Priority date: 1957-04-26
Filing date: 1958-04-08
Publication date: 1962-04-03
Anticipated expiration: 1979-04-03
Also published as: FR1195079A; CH374892A; BE567154A; DE1034022B

Description

3,028,237 Patented Apr. 3, 1962 thee 3,028,237 MASKING F CYAN IMAGES IN (101.011 PHQTOGRAPHY Karl Loitler, Leverkusen, Germany, assignor to Agra Alrtiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Apr. 8, 1958, Ser. No. 727,043 Claims priority, application Germany Apr. 25, 1%7 8 Claims. (Cl. 96-9) The present invention relates to a process and to materials for producing cyan images which are combined with red masking images.

For improving the color reproduction when the subtractive color process is used, it is known to employ colored masks which have a gradation opposite to that of the partial image to be masked and absorb in the range of unwanted secondary color density in the partial image dyestutf. In practice yellow masks are most frequently used for masking the magenta dyestuff, and red masks are used for correcting the secondary color densities of the cyan-dyestuffs.

In the case where the colored correcting masks are not on a separate support but in a multi-layer material that includes the image to be masked, two fundamental principles have been proposed for preparing the masks:

(1) Conversion of the residual color coupler after color development of the primary image into a colored correcting image by subsequent treatment with solutions of suitable diazonium compounds or aldehydes, for example.

An obvious disadvantage of this process is the increased complication of the processing and the increased likelihood of defective results which is connected therewith,

as well as in the difiiculty of excluding an analogous but undesired color reaction with the yellow coupler.

(2) Recoupling of colored color couplers already in the layer by color development to give image dyestufis, that portion which is not recoupled remaining as a colored mask.

An essential disadvantage of the recoupling process is that the layers which are dyed from the outset lower the light sensitivity of the silver halide. This is especially so when interchange of the layers, desirable for other reasons, is carried out, for example where a red-dyed layer for masking the cyan image is arranged above the greensensitive layer.

It has now been found that a red masking image for the cyan partial image can be obtained in a very simple manner and without the disadvantages referred to if one or more diaminesof the general formula are incorporated into the layer along with the cyan coupler, R in this general formula representing a straight or branched chain alkyl radical, for example with at least 6, preferably 10 to carbon atoms and R representing a solubilizing group, for example a sulfonic acid or carboxyl group. Orthodiamines of this type are inert with respect to the color developing bath but in a subsequent silver bleaching bath, for example with potassium ferricyanide, undergo an oxidizing reaction with the residual cyan coupler to give red dyestufis, so that, during the conventional processing and without additional measures or baths being necessary, a red correcting image is formed with a gradation opposite to that of the cyan image, that is to say a positive red masking image in case that the cyan image is negative and a negative red masking image in case that the cyan image is positive. In accordance with the invention, the optimal density of the red masking image can easily be obtained by adding an appropriate proportion of the diamine to the silver halide emulsion layer, whereas this is not readily possible when colored couplers are used. The diamines are preferably applied in amounts of 1-6 g. and the cyan color coupler in amounts of 520 g. per 1 kg. of silver halide emulsion.

Examples of suitable diamines are:

4-octadecylamino-3-aminobenzene sulphonic acid, 4-octadecylamino-3-aminobenzoic acid, 4-dodecylamino-3-aminobenzoic acid,

The diamines can be produced in known manner by the replacement of substituents, such as chlorine or bromine, in the ortho-position to the nitro group by the radical of a primary amine and subsequent reduction of the nitro group to the amino group. For example 4-octadecylarnino-3-amino-benzene sulphonic acid is formed from 4-chloro-3-nitrobenzene sulphonic acid by the use of stearyl amine and subsequent reduction.

The oxidizing bath necessary for forming the red masking image corresponds to the potassium ferricyanide bleaching baths usual for color development.

Example 1 100 g. of a red-sensitive silver bromide emulsion, which contains 1.2 g. of 3-(l'-hydroxy-2'-naphthoyl)-amino-4- methyl octadecylaminobenzene sulphonic acid or a water soluble salt thereof, such as the sodium-, potassiumor ammonium salt, and 0.3 g. of 4-octadecylamino-3-aminobenzoic acid, is cast on to a support, and the resulting material is dried, exposed and processed in the following baths.

Color developer:

1 litre of water, g. of potassium carbonate, 2 g. of sodium sulphite, 1.5 g. of potassium bromide, and 2.5 g. of p-diethylaminoaniline sulphate. Bleaching bath:

1 litre of water, g. of potassium ferricyanide, and 50 g. of potassium bromide. Fixing bath:

1 litre of water and 200 g. of sodium thiosulphate.

A negative cyan image and a positive red correcting image are formed in the processed layer.

The above diamine is obtained as follows:

3-nitro-4-octadecylamino-benzoic acid is produced in analogous manner as the corresponding sulfonic acid derivative disclosed in Example 4 below, by replacing the Z-nitro-1-chlorobenzene-4-sulfonic acid by the equivalent amount of 4-chloro-3-nitro-benzoic acid. The aminated nitro compound thereby formed is catalytically reduced in the presence of Raney-nickel in met-hanolic solution.

There is obtained a reddish-grey powder decomposing at 203 C. when heated.

The aforementioned diamino compound may be replaced by the equivalent amount of 3-arnino-4-dodecylamino-benzoic acid which is obtained in analogous manner as the octadecylderivative. Point of decomposition 194 C.

Example 2 A green-sensitive silver bromide emulsion, containing 1.2 g. of 1-(4-phenoxy-3-sulphophenyl)-3-heptadecyl pyrazolone per 100 g., is cast on to the red-sensitive layer referred to in Example 1. Another layer which contains colloidal silver as yellow filter is cast thereon, followed by an optically non-sensitized silver bromide emulsion containing 1.5 g. of -(4-(stear0ylamino)-benzoyl acetarnino)-isophthalic acid per 100 g. After exposure and processing as in Example 1, a negative and complementary color image is formed, the cyan layer of which also contains a positive red masking image.

Example 3 The multi-layer material cast as described in Example 2 is modified by interchanging the red-sensitive and greensensitive layers. After the modified material has been exposed and processed in the same way as in Example 2, practically no loss in sensitivity of the green-sensitive layer is found, although in this case the red mask is above the green-sensitive layer.

Example 4 An optically non-sensitized silver bromide emulsion containing 1.4 g. of 3-(p-anisoyl acetamino)-4-methyl octadecylaminobenzoic acid per 100 g. is cast on to a support and dried. A green-sensitized silver chloride emulsion containing 1.4 g. of 1-phenyl-3-heptadecyl-5- pyrazolone-3'-su1phonic acid per 100 g. is coated above the silver bromide emulsion. A red-sensitized silver chloride emulsion with 1.1 g. of l-hydroxy-Z-naphthoyl octadecyl amide-4-sulphonic acid, to which there have also been added 0.3 g. of 4-octadecyl amiuo-3-aminobenzene sulphonic acid, is cast above the green-sensitized silver chloride emulsion. After exposure and processing of the resulting material as in Example 1, a complementary negative image is obtained, the yellow partial image of which is in the lowermost layer, the magenta partial image of which is in the middle layer and the cyan partial image of which, together with a red correcting image, is in the uppermost layer. The last-mentioned diamine is produced as follows.

A mixture of:

26 g. of the sodium salt of 2-nitro-1-chlorobenzene-4- sulfonic acid,

26.4 g. of stearylamine,

9 g. of sodiumbicarbonate,

120 cc. of water,

100 cc. of butanol,

25 cc. of methanol is refluxed for hours. Thereafter about 150 cc. of solvent are distilled off, the residue is stirred with 250 cc. of hot methanol, cooled and sucked oil. 30 g. of the 2-nitrooctadecylanilinei-sulfonic acid (sodium salt) are dissolved in 250 cc. of hot glacial acetic acid. The solution obtained is slowly added While stirring to 80 cc. of a solution which contains per 100 cc. of concentrated hydrochloric acid 60 g. of SnCI ZH O; the hot mixture has added thereto 100 cc. of methanol and is stirred until the yellow color has disappeared. After cooling the compound formed is sucked oil, washed with methanol and dried at 60 C. Point of decomposition 247 C. The corresponding dodecylderivative has a point of decomposition of 258 C.

The cyan couplers to be used for carrying out the process of the present invention are well known in the art. They are derivatives of phenol or u-naphthol having in ortho or para-position to the phenolic hydroxy group a coupling function. Such phenolic compounds are either unsubstituted in the aforementioned positions or they are substituted by substituents which are split off during coupling with the oxidation products of the lCOlOI' forming developers such as primary aromatic amino compounds, such substituents being preferably sulfonic acid groups or halogen atoms. Such couplers are preferred which are fast to diffusion, this property being for instance obtained by the presence of higher alkyl radicals having for instance 10 to 20 carbon atoms. Moreover these couplers may contain solubilizing groups such as sulfonic acid or carboxylic acid groups. Such couplers are for instance disclosed in US. Patents 2,184,849; 2,324,832; 2,357,395 and 2,366,324. The couplers and/or the diamines may also be incorporated in a water permeable, water insoluble solvent as described for instance in US. Patents 2,304,940 and 2,322,027 before they are added to the gelatino silver halide emulsions.

As to the bleaching bath which is used for carrying out the process of the present invention it is preferred to use aqueous solutions of water soluble ferricyanides, the pH value of said solutions being adjusted to about 5 to 8 and the concentration to about 2 to 10 percent by weight. However, it is also possible to use other bleaching baths customary in the art as for instance aqueous solutions of potassium bichromate.

I claim:

1. in the process for the production of a cyan photographic image with a red correcting mask, the steps of providing a silver halide emulsion layer containing a cyan coupler selected from the class consisting of phenols and naphthols that couple with the oxidation products of a primary aromatic amine developer in a position orthoand parato the phenolic hydroxy group of the coupler to form a cyan dye, and a diamine of general formula where R represents an alkyl radical having at least 6 carbon atoms and R represents a solubilizing group selected fromthe class consisting of sulfonic acid and carboxylic acid groups, said coupler having a concentration of from 5 to 20 grams per kilogram of emulsion and the diamine having a concentration of from 1 to 6 grams per kilogram of emulsion, exposing the emulsion to an optical image, developing the exposed emulsion with said developer to form a cyan image in the illumina-ted portions of the emulsion, and subjecting the developed emulsion to a bleaching operation with a bleaching bath selected from the class consisting of ferricyanide and chromate bleaching baths to remove the developed silver and thereby produce a red masking dyestuft by reaction of said diamine with the residual coupler in the unillumina-ted portions of the emulsion.

2. The combination of claim 1, wherein the diamine is 4-octadecylamino-3-aminobenzene sulphonic acid.

3. The combination of claim 1, wherein the diamiue is 4octadecylamino-3-aminobenzoic acid.

4. The combination of claim 1, wherein the diamine is 4-dodecylamino-3-arninobenzoic acid.

5. A photographic material comprising a silver halide emulsion layer containing a cyan coupler selected from the class consisting of phenols and naphthols that couple with the oxidation products of a primary aromatic amine developer in a position orthoand parato the phenolic hydroxy group of the coupler to form a cyan dye, and a diamine of the general formula Where R represents an alkyl radical having at least 6 carbon atoms and R represents a solubilizing group selected from the class consisting of sulfonic acid and carboxylic acid groups, said coupler having a concentration of from S to 20 grams per kilogram of emulsion and the diamine having a concentration of from 1 to 6 grams per kilogram of emulsion.

6. A photographic material according to claim 5 Wherein the diamine is 4-octadecylamino-3-arninobenzene sulphonic acid.

7. A photographic material according to claim 5 wherein the diamine is 4-octadecylamino-3-aminobenzoic acid.

8. A photographic material according to claim 5 wherein the diamine is 4-dodecylamino-3-aminobenzoic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,697,662 McQueen et a1. Dec. 21, 1954 10 2,805,158 Gauguin et al. Sept. 3, 1957

Claims

1. IN THE PROCESS FOR THE PRODUCTION OF A CYAN PHOTOGRAPHIC IMAGE WITH A RED CORRECTING MASK, THE STEPS OF PROVIDING A SILVER HALIDE EMULSION LAYER CONTAINING A CYAN COUPLER SELECTED FROM THE CLASS CONSISTING OF PHENOLS AND NAPHTOLS THAT COUPLE WITH THE OXIDATION PRODUCTS OF A PRIMARY AROMATIC AMINE DEVELOPER IN A POSITION ORTHO- AND PARA- TO THE PHENOLIC HYDROXY GROUP OF THE COUPLER TO FORM A CYAN DYE, AND A DIAMINE OF GENERAL FORMULA