|Publication number||US2343051 A|
|Publication date||Feb 29, 1944|
|Filing date||Jul 13, 1940|
|Priority date||Jul 13, 1939|
|Publication number||US 2343051 A, US 2343051A, US-A-2343051, US2343051 A, US2343051A|
|Inventors||Alfred Frohlich, Gustav Wilmanns, Wilhelm Schneider|
|Original Assignee||Gen Aniline & Film Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (5), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
' :raphic color images.
Patented Feb. 29, 1944 I PROCESS FOR PREPARING PHOTOGRAPHIC SILVER HALIDE EMULSIONS FOR MULTI- COLOR PHOTOGRAPHY Alfred Friihlich and Wilhelm Schneider, Dessau,
and Gustav Wilmanns, Wolfen, Kreis Bitter- !eld, Germany, assig'nors to General Aniline & Film Corporation, New York, N. Y., a corpora- I tion of Delaware No Drawing. Application July 13, 1940, Serial No. 345,364. In Germany July 13, 1939 8 Claims.
The present invention relates to color photosraphy and more particularly to an improved method of preparing photographic silver-halide emulsions for multi-color photography.
It is known that color formers fast to difiusion .re employed for the manufacture of photo- These color formers fast difiusion cannot be removed from the emul- :ion layer by the usual photographic treating maths, for instance by washing, though they have men added to the silver halide emulsion in dissolved form. As such color formers there were proposed for instance substances which are insoluble in aqueous alkalies, the hydrogen ion concentration of which corresponds approximately to that of the usual photographic developing solutions, which, however, are soluble at increased alkalinity, for instance in diluted caustic soda solution. These, color formers are incorporated into the emulsion dissolved in diluted caustic soda solution. It is known furthermore to dissolve scarcely soluble components in organic solvents, for instance methanol partly with the aid of caustic alkalies and to add thesesolutions to the photographic emulsion, thereby accomplishing the necessary dispersion of the precipitated diflicultly soluble substance in the solution by means of violent stirring or by means of precipitating or dispersing agents.
I If there are employed color formers fast to diffusion which contain groups effecting better water solubility, such as acidor hydroxyl groups, they may be dissolved in diluted soda solution, whereby these soda-alkaline solutions possess a a pH-value which approximately corresponds to that of the photographic developing solution. This pH-value amounting to about 11, is, however, not very suitable for photographic emulsions, especially for sensitized emulsion layers, since the addition of the solution of the color former influences-the pH-value. This causes nearly always an increasein sensitivity which, however, is entirely undesired at this moment, as the process is hardto control. Such highly sensitive emulsions, moreover, are inclined to fogging and possess low keeping quality.
The present invention has for an object to provide color components which are soluble in the emulsion layer and which are fast to diffusion with respect to the difierent photographic treating processes afterwards.
A further object is to provide silver halide emulsions containing the color forming components fast to diflusion. Y
A further object is to provide an improved film for color photography having superposed silver halide emulsion layers, each layer containing a color component fast to difiusion.
These and other objects will become apparent from the following specification.
It has been found, that these difficulties can be avoided and that excellent stable emulsions for multi-color photography are obtained, if a pH- value of about 5-8 is chosen for the finished emulsion layers. For that purpose it is first of all necessary that the color formers fast to difiusion which are to be added to the emulsion are soluble at a pH-value of less than 9. To dissolve therefore these components an alkalinity must be sufficient which in no case is higher than pH=9. In order to accomplish the desired solubility with regard to color components fast to difiusion, the kind and number of the groups which effect improved water-solubility and which have to be introduced into the molecule, have to be chosen according to the kind and number of the molecule radicals which effect fastness to diffusion.
Such color formers fast to difiusion which possess molecule-radicals and acid groups incorporating fastness to difiusion or which have other substituents efiecting sodaor water-solubility are for instance the following: l-naphthol-Z-carboyl amino phenyl-3'-octadecylamino-4'-sulfo acid- 4 -sulfo acid, 1 naphthol-2-carboylaminophenyl-3-octadecylamino-4'-carboxylic acid 4- sulfo acid, 1-naphthol-2-carboylaminophenyl-3- oleylamin'o-4'-sulfo acid-4-sulio acid, l-naph- I thol- 2 -carboy1aminophenyl-3'-d0decylamin0-4'- thol-2-carboylamino-3' sulfooleylaminobenzene- 4-sulfo acid, di-1,-1-naphthoxy-2,2'-carboyl-3- stearylamino benzidine 4,4 sulfo acid, 1,2,3-
xylenolcarboyloctadecylamino 4 sulfo acid, 1-
naphthol 6 sulfurylheptadecylamino 4 sulfo acid, 6 methoxy-l-naphthol 2 carboyl-sulfooleylamino- 4 -su1f0 acid, l-naphthol- 2 -carboylamino 4-methylhepta decylaminobenzene-3'- sulfo acid-4'-sulfo acid, l-naphthol-2-carboy1 aminoAFmethylsulfo octadecylaminobenzene- 4-sulfo acid, 8-octadecylethylamino-l-naphthol- 2,4-disulfo acid, mixture from a-oxynaphtholc acid and polyethyleneoxide, mixture from a-oxynaphthoic acid 'and aminophenylpolyethyleneoxideether, 4 sulfooleylaminobenzoylacetylamino 3,4' benzenedicarboxylic acid, laurylacetic acid aminebenzenedicarboxylic acid, 1-(3,6'- dimethyl-3-stearoylamino) phenyl-3-methyl-5- pyrazolone-4'-sulfo acid, 1,3'-carboxyphenyl- 3- 4'-sulfooleylaminophenyl-5-pyrazolone, 1,5'-carboxy- 3' sulfooleylaminophenyl- 3 -,furfuryl- 5 pyrazolone, l-phenyl- 3 -palmitoyl-5-pyrazolone- 3',5-disulfo acid, 1-plienyl-3-palmitoyl-5-pyrazolone-3-sulfo acid 4'- methylaminoethanesulfo acid, l-phenyl- 3 -sulfoheptadecyl- 5 -pyrazolone, 1,3'-sulfoo1eylaminophenyl- 3 -methyl-5-pyrazo-.
lone, 1,3-sulfooleylaminophenyl 5-pyrazolone-3- acetic acid, 5-pyrazolone-3-acetic acid-l-(p-octadecyl-a-carboxylic acid) Color formers fast to difiusion according to the below-mentioned U. S. patents are, generally speaking, very suitable, the solubility of which has been set by the introduction of groups efiecting improved water solubility to a pH-value being smaller than 9: 2,178,612, of November 7,
1939; 2,179,238, of 'November 7, 1939; 2,179,244, of November 7, 1939; 2,186,732, of January 9, 1940; 2,186,849, of January 9, 1940; 2,186,850, of January 9, 1940; 2,280,722 of April 21, 1942; 2,307,399,
January 5, 1943.
The components may also be dissolved at a stronger alkalinity than pH-value=9 and the so lution may then be set at a pH-value of at least not more than'9 by adding diluted acid. Furthermore the solution of a color former having stronger alkalinity may be added to the emulsion during the manufacturing process or before casting and there may be added to the emulsion so much of a diluted acid or of an acid salt, as is necessary for the neutralization of the alkali which is not bound to the color former, Condition is, however, in all these cases, that the colorformers are soluble at a pH-value of less than 9.
The emulsionsnaturally may contain all modifying agents suitable for the manufacture ofphotographic emulsions. With regard to the final 2,343,051 I I V the effect of the to be taken into considermodifying agents has pH-value of the emulsion, also ation.
- We claim:
= 1. Process for the manufacture of silverhaiide emulsions for color photoxraphy. which process comprises dissolving in alkali, color components fast to diflusion in gelatin and completely soluble at a pH value of about 9, incorporating the alkaline color former solution into the emulsion at a pH of about 9, and reducing the alkalinity of the mixture by neutralizing to a pH value of from 5 1:08.
2. The process as defined in claim 1, wherein the color component is fast to diffusion by virtue of the presence therein of a long aliphatic chain.
3. The process as defined in claim 1, wherein the color component is fast to diffusion by virtue of the presence therein of a long aliphatic chain and wherein the color component contains a plurality of water-solubilizing groups.
4. The process as defined in claim 1, wherein the color component is fast to diffusion by virtue of the presence therein 01 a long aliphatic chain and wherein the color component contains a plurality of sulfonic acid groups.
5. The process as defined in claim 1, wherein the color component is a naphthol containing a long aliphatic chain.
6. The process as defined in claim 1, wherein
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|U.S. Classification||430/546, 430/554, 430/552|