US2673149A

US2673149A - Quaternary salts in mixed grain photographic emulsions

Info

Publication number: US2673149A
Application number: US251833A
Authority: US
Inventors: Burt H Carroll
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1951-10-17
Filing date: 1951-10-17
Publication date: 1954-03-23
Anticipated expiration: 1971-03-23
Also published as: DE971466C; BE514795A; GB722231A; FR1099927A

Description

Patented Mar. 23, 1954 -.QUATERNAR.Y

SALTS IN iEMIXED ,PHOTOGRAPHIC EMULSIONS Burt H. Carroll, Rochester, N. Y., assignor to iEastman:.:Kodak Company, Rochester, N. Y., a

:cornorationzof NemJersey "N01 Drawing: Application October "Serial No. 251383 (UL .v95-q2) fiiclaims.

'Ihisdnventiofihas to"dowith'photography and particularly to the sensitizing of mixed -grain emulsions.

'Ihesensitization of emulsions has-been described in carroll andiHan- A sensitizer diffusion. However, aimision is :seldom :completely eliminated and difficulties halide grains varies with the silver halide used. In general, affinity is less for silver chloride than for silver bromide, so that there is the most difiiculty when itiis necessary to aavoid diffusion of 'Thisisituation is three-color-emul- :sion "where, it 1 is :desirable to use high chloride .aemu'lsions IfOI;th8 red1sensitiveandrgreemsensr tive grains so1thatt.theirr;blue sensitivitywill :be negligible compared1to the blue-sensitive grains, or so that it canbe eliminated a yellow printing filter.

It is, therefore, an object of the present invention to provide a novel method of sensitizing .mixedngrain photosraphic-emulsions. A further .Qbjectis t'o provide a method for; preventing ssensitizer. diffusioni inmixed grain emulsions. A still further object is torprovidenovel mixed grain gphotographicproducts. 'Other objects will .ap- .pear .from the, following 1 description 1 of any in- ,vention.

These objects are accomplished quaternary salts on the surface of-the silver halide grainsof a mixed, grain photographic emulsion.

My invention comprises in general the provision of a mixed grain photographicemulsion having to different spectral regions, in .a .hydrophylic carrier, one. .or. more of .the sets .of. grains; having a...quaternary.salt.adsorbedthereto.

L'Ihe. silver'halide may ,be. silver chloride, silver .bromide, .silver chlorobromide, silver bromoio- ,;dide,..etc., .in..a..carrierv such. .asgelatin, polyvinyl valcohol, hydrolyzed cellulose esters or ethers, etc.

The quaternary salts which .I .may use are quaternary salts of compounds=having the formula:

entirely by use of g by adsorbing of'the sensitizing dye for the silver .ing a rfllSBd-OII 1 benzothiazole,

benzothiazolium perchlorate,

where-Zrrepresents {the atoms,- necessary to complete an azole ring, preferably an azole ringahavarylene nucleus, e. g thiazole, ,benzoxazole, :benzoselenazole, .naphthothiazole, etc., and nisyan integer-from 5. 13010. ,The quaternary salt may; be awhloride,

.bromide, (iodide, nsulfate, ,petoluene :sulfonate, perchlorate etc.

The quaternary saltsxwhich.-l;.prefer to use have the .-formula:

-e. g. chloride, bromide, iodide, sulfate, para- "toluene. sulfonate, etc.

The following are suitable compounds: Pentamethylene bis abenzo thiazolium perchlorate, heptamethylene -1bisidecamethyleneebisbenzothiazolium perchlorate. Other" bis quaternary salts of antifoggants may be used, c. .g. the bis quaternary-salts of the thiazoles, naph- "stitution such as alkyl, aryl,.alkoxy. or halogen *Thetoptical sensitizing dyes useful in my mixe'd grain emulsions embrace the "following:

( 1.) Carbocyanines derived from ,e-naphtho- "These include .carbo cyaninechloride. 3,3 -'dimethyl 9 -;phenyl-- 4.5.4.25 :dibenz ithiacarbocyanine bromide.

4,5,425" dibenzthiacarbocya nine bromide.

these grains if used on utes at 50 chlorate, in the amount 3 dichloroselenacarbocyanine bromide (made by the method of White U. S. Patent 1,990,681, using 5-chloro-2-methylbenzoselenazole instead of 2- methylbenzoselenazole). These are red sensitizers.

(3.) 3, 3" bocyanines and oxacarbocyanines White U. S. Patent 2,478,366)

These include 3,3 dimethyl 8,10 m

anine bromide.

3,3 dimethyl 8,10 m

anine bromide.

- dimethyl 8,10 aryloxythiacar (Brooker and toloxythiacarbocy toloxyoxacarbocy 1 and 1' ,3-diethyl-4,5-benz-6-methylthia-2'-cyanine bromide (Brooker U. S. Patent 1,935,696). These are green sensitizers.

The optical sensitizing dyes are preferably used at a concentration of from '7 to 50 mg. of sensitizing dye per liter of silver halide emulsion containing about 0.25 gram mole of silver halide per liter of emulsion.

According to my invention, the silver halide emulsion is treated with the quaternary salt before or after optical sensitizing. In the case of the blue sensitive component of the mixture, no optical sensitizing dye is ordinarily used. With the red-sensitive and green-sensitive components of the mixture, the silver halide is optically sensitized to the desired spectral region and is then treated with the quaternary salt, although the quaternary salt may be omitted from the unsensitized bluesensitive grains. The amount of quaternary salt may vary from about 20 to 400 milligrams per mole of silver halide. To form the mixed grain emulsion, silver halide emulsions sensitized to different spectral regions are mixed in approximately equal amounts or in amounts containing approximately equal quantities of silver.

, -The following example illustrates the forma tion of a mixed grain emulsion according to my invention:

To a blue-sensitive silver halide emulsion containing 98 mole-percent silver bromide and 2 mole percent silver chloride there was added decamethylene-bis-benzothiazolium perchlorate in the proportion of 1'75 mg. per mole of silver halide and the emulsion was digested with it for 5 minutes at 50 C., then cooled to coating temperature of about 40 C.

A red-sensitive equal 'to 20 mole-percent of the silver and chloride in excess of the remaining 80 mole-percent was sensitized with 3,3-dimethyl-9-phenyl- 4,5,4,5'-dibenzthiacarbocyanine chloride, 88 mg. per mole of silver halide, and digested 5 min- C. with the dye. After cooling to 40 decamethylene-bis-benzolthiazolium peroi 175 mg. per mole of silver halide was added.

To a green-sensitive emulsion of the same emulsion containing bromide.

4 silver halide composition as the red-sensitive emulsion, there was added 3,3,9-triethyl-5,5'- diphenyl oxacarbocyanine bromide in the amount of 88 mg. per mole of silver halide, the emulsion was digested 5 minutes at 50 C. and then cooled to C. and decamethylene-bis-benzothiazolium perchlorate was added in the amount of 1'75 mg. per mole of silver halide.

The usual spreading agents and hardener were added to each of the emulsions and. the emulsions were then mixed in amounts containing equal amounts of silver and immediately coated.

After drying, this coating was exposed to a color chart and processed as described in Example-4 of U. S. Patent 2,592,243 of Carroll and Hanson. There' was no detectable diffusion of sensitizing dyes.

It will be understood that these examples are illustrative only and that modifications may be made in the method and material within the scope of the appended claims.

I claim:

1. A mixed grain photographic emulsion containing at least two sets of silver halide grains sensitive to difierent spectral regions, at least one of said sets of grains being sensitized with a cyanine sensitizing dye and at least one of said sets of grains having adsorbed thereto a quaternary salt of the structure:

CH C104 C104 3. A mixed grain photographic emulsion containing sets of silver halide grains sensitive respectively to the blue, green and red spectral regions, at least one of said sets of grains bein sensitized with a cyanine sensitizing dye and at least said blue-sensitive grains having adsorbed thereto a quaternary salt of the structure:

C C104 C104 silver halide grains by diffused optical sensitizer in a BURT H. CARROLL.

References Cited in the file of this patent UNITED STATES PATENTS Name Carroll et a1.

Number Date June 30, 1942

Claims

1. A MIXED GRAIN PHOTOGRAPHIC EMULSION CONTAINING AT LEAST TWO SETS OF SILVER HALIDE GRAINS SENSITIVE TO DIFFERENT SPECTRAL REGIONS, AT LEAST ONE OF SAID SETS OF GRAINS BEING SENSITIZED WITH A CYANINE SENSITIZING DYE AND AT LEAST ONE OF SAID SETS OF GRAINS HAVING ADSORBED THERETO A QUATERNARY SALT OF THE STRUCTURE: