Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/34—Fog-inhibitors; Stabilisers; Agents inhibiting latent image regression
  • G03C1/346—Organic derivatives of bivalent sulfur, selenium or tellurium

Definitions

• This invention relates .to' fog-inhibiting agents and stabilizers for photographic emulsions, and to photographic emulsions containing them. 7
• Fog usually appears ov'er the whole area of the sensitive coating, but when severe, it frequently is non-uniform. Fog may al'sobe caused by exposure to chemicals, for example, hydrogen sulfide and other reactive sulfur compounds, hydrogen" peroxide vapor, and strongly reducing materials.
• v antiice benzothiazoline nucleus wherein the benzene ring thereof can contain substituents, such as chlorine, bromine, methyl, ethyl, methoxyl, ethoxyl, etc.
• Q represents an oxygen atom or imino (NH).
• Especially useful compounds embraced by Formula 1'' above are those represented by the following general formula:
• R, D and Q each have the values given above, 11 is 1 or 2 and R represents a hydrogen atom or a carboxyl group (i. e., carbox-yl" or a water-soluble salt thereof, such as the alkali metal salts (e. g., sodium, potassium,
• foggants and stabilizers may protect, tosome extent
• an a'ntif'o'ggant protects .against spontaneous growth 'of fog during prolonged storage or storage at high: temperatures and humidities, or during development to max'imum contra'st and'speed', or both.
• -It is, accordingly, an object of our a method for stabilizing photographic emulsions.
• a further object of our invention is to maintain the sensitivity and fog of silver halide emulsions at or close to initial optimum values under keeping conditions of high temperature and humidity.
• a further object is to provide photographic silver halide emulsions containing antifoggants' or stabilizers.
• I. s R I a l I C. II Q invention' to' provide sents the non-metallic atoms necessary to complete a thia'z'olidine nucleus, a tetrahydrothiazine nucleus or a etc.), or ammonium or organic amine salts, such as triethylamine, triethanolamine, pyridine, etc.).
• the fog inhibitors which we propose to use are, added to the emulsion duri g; thepro'c'ess of manufacture, to avoid loss of sensitivity and to inhibit the growth of fog with passage of time under non-ideal conditions of storage.
• a solution of the compounds of the invention when added in suitable concentration," before coating, to unsensitized, chemically sensitized, or optically sensitized photographic emulsions does not appreciably affect the sensitornetric values for sensitivity and fog when measurementsare made soon after coating.
• sen'sitometric measurements are made at appreciable intervals of time, at elevated temperatures and dry or somewhat humid conditions these compounds do stabilize photographic speed and maintain fog at a low level.
• the preparation of silver halide emulsions involves three separate operations: (1) the emulsification and digestion or ripening of the silver halide, (2) the freeing of the emulsion from excess soluble salts, .usually by washing, and (3) the second digestion or afterripening to obtain increased sensitivity (Mees: The Theory of the Photographic Process (1942)).
• the photographic emulsions used in practicing our invention are generally of the developing-out type; also, it is to be understood that photographic emulsions of varying
• antifoggant compounds used in our invention have been found particularly useful when employed in conjunction with gelatino-silver-bromiodide emulsions, although they can also be advantageously employed for stabilizing other silver halide emulsions, such as gelatino-silver-chloride, bromide, chlorobromide, chlorobromiodide, etc.
• Patent 2,448,060 and as antifoggants in higher amounts, as described in Trivelli and Smith U. S. Patents 2,566,245 and 2,566,263.
• the emulsions can also be chemically sensitized with gold salts as described in Waller and Dodd U. S. Patent 2,399,083, or stabilized with gold salts as described in Damschroder U. S. Patent 2,597,856 and Yutzy and Leermakers U. S. Patent 2,597,915.
• Suitable compounds are potassium chloroaurite, potassium aurithiocyanoate, potassium chloroaurate, auric trichloride and 2-aurosulfobenzothiazole methochloride.
• the emulsions can also be chemically sensitized with reducing agents such as stannous salts (Carroll U. S. Patent 2,487,850), polyamines such as diethylene tri amine (Lowe and Jones U. S. Patent 2,518,698), polyamines, such as spermine (Lowe and Allen U. S. Patent 2,521,925), or bis-(fi-aminoethyl) sulfide and its watersoluble salts (Lowe and Jones U. S. Patent 2,521,926).
• reducing agents such as stannous salts (Carroll U. S. Patent 2,487,850), polyamines such as diethylene tri amine (Lowe and Jones U. S. Patent 2,518,698), polyamines, such as spermine (Lowe and Allen U. S. Patent 2,521,925), or bis-(fi-aminoethyl) sulfide and its watersoluble salts (Lowe and Jones U. S. Patent 2,521,926)
• the emulsions can also be stabilized with the mercury compounds of Allen, Byers and Murray U. S. Patent 2,728,663, Carroll and Murray U. S. Patent 2,728,664, and Leubner and Murray U. S. Patent 2,728,665.
• the stabilizing and contrast-increasing compounds of our invention are effective in the presence or absence of optical or spectral sensitizing dyes. Since spectral sensitizing may affect stability of emulsions with respect to sensitivity, fog and latent image changes, the action of the compounds of our invention is not completely independent of spectral sensitizing or other emulsion variables. We have found, however, that both unsensitized emulsions and emulsions sensitized with cyanine or mero- -cyanine dyes, or both, can be treated with the aboveformulated compounds according to our invention. We have noted in certain instances that the compounds of our invention have a sensitizing action of their own in additio to the other effects noted above. In other instances, these compounds stabilize the speed of the photographic emulsions, when the emulsions are subjected to adverse keeping conditions.
• the following table will serve to illustrate the antifoggant and stabilizing action provided by the compounds of our invention, when added to an ordinary negative gelatino-silver-bromiodide emulsion.
• the antifoggant and stabilizing action was determined by incubation of the emulsions for one week at a temperature of 120 F., and two weeks at a temperature of 120 F. in certain cases, and at constant relative humidity (obtained by placing the emulsions in closed containers, the embient temperature being about 70 F. and relative humidity about prior to sealing the containers).
• the etficiency of the various antifoggants was determined by measuring the speed, gamma and fog of the in-
• the emulsions can also be chemically sensitized by any i of the accepted procedures.
• the emulsions can be digested with naturally active gelatin, or sulfur compounds can be added such as those described in Sheppard U. S. Patent 1,574,944 and U. S. 1,623,499, and Sheppard and Brigham U. S. Patent 2,410,689.
• the emulsions can also be treated with salts of the noble metals such as ruthenium, rhodium, palladium, iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic weight greater than 100.
• Representative compounds are ammonium chloropalladate, potassium chloroplatinate and sodium chloropalladite, which are used for sensitizcubated emulsions containing an antifoggant and comparing these measurements with those of the same batch of emulsion before incubation, as well as comparing these measurements with those made on an identical batch of photographic emulsion containing no antifoggant.
• alkaline emulsions water s'oluble salts of the compounds of Formula I or II above which contain a carboXyl group are formed to some extent, If desired, these compounds can be first addedtoa dilute alkaline solution and this solution added directly to the photo'- graphic silver halide emulsion;
• fog-inhibiting agents useful in practicing our invention' can be used in various kinds of photographic emulsions. In addition to being useful in ordinary non-sensitized emulsions, they can also be used in orthochromatic, panchromatic and X-ray emulsions. If used with sensitizing dyes, they can be added to the emulsion before or after the dyes are added.
• Suitable dispersing agents for the silver halide used in our invention comprise gelatin or other colloids, such as colloidion, albumen, cellulose organic derivatives, synthetic resins, etc. Synthetic dispersing agents are particularly useful where it is desired to demonstrate the effect of the compounds of our invention in increasing the contrast or gamma, in silver chloride emulsions.
• the compounds can also be used in emulsions containing incorporated couplers or emulsions which are developed in processing solutions containing couplers.
• the optimum amount of compound to be used as a fog-inhibiting agent can be determined by making the customary tests employed in emulsion making.
• the optimum amount for a given emulsion will vary depending upon the presence of emulsion addenda, such as chemical sensitizers, spectral sensitizing dyes, etc.
• emulsion addenda such as chemical sensitizers, spectral sensitizing dyes, etc.
• emulsion addenda such as chemical sensitizers, spectral sensitizing dyes, etc.
• the antifoggants of our invention function advantageously in wherein R represents a hydrogen atom or a carboxyl group, and r1 rep'rfesents'l or 2 witna ketone compound selected from those represented by the following general formula:
• R has the values given above and R represents a ,fi-carboxyethyl group or an o-carboxyphenyl group (substituted or not, as indicated above).
• the compounds of Formulas I and II wherein R represents a methyl group are prepared by reacting an acid-addition salt of a'compound of Formula III '(e. g., the hydrochloride, hydrobromide, etc.) with the ketone compounds of Formula IV wherein R is methyl.
• R is generally a carboxyl group and R is a fi-carboxyethyl group.
• the compounds of Formula I wherein D represents the non-metallic atoms necessary to complete a benz'o thiazole nucleus can be prepared by reacting an o-a'minofbenzenethiol with the compound of Formula IV; This reaction is quite similar to that wherein the compounds of Formula III (R is hydrogen) are reacted with the compounds of Formula IV.
• Example A Lactam of 4-carboxy-2-(fl carboxyethyl)- Z-methylthiazolidine cm-sH The resulting solution was refluxed for ten minutes and allowed to cool. The product separated as an oil. The mixture was diluted with water and the product extracted B l I with ether several times. On evaporation of the ether HNHHC1 22 extract (dried over anhydrous magnesium sulfate) the OOH CH; product crystallized out. The product recrystallized from 4 alcohol-water melted at 97 100 C.
• the reaction mixture was j- DeCOmPOSCd 9 1
• the heated on the steam bath for 5 e i ut 50 1 f evidencefor the ring closed amidlne structure was estabethyl alcohol were added and the mixture was allowed lished 011 t basis of q 0f tl'lple'bolld adsorptlon to cool.
• a small amount of cysteine was filtered off, and 111 i I'eg10I1 Q l 111 l Infrared and the 6X33- the clear mother liquor upon standing for several weeks Q y f fy 0f the llltfogen as Shown y the p at C. gave long colorless needles (2.5 grams in the tr16 tltratlon curve.
• Example C Lactam of 4-carboxy-2-(o-carboxyphenyl)- thiazolidine
• phthalaldehydic acid phthalaldehydic acid
• cysteine hydrochloride 20 ml. of hot water.
• 1.58 cc. 0.02 mole
• pyridine pyridine
• the reaction mixture was warmed on the steam bath for 15 minutes, and left at F. for two days.
• the solution was then heated on the steam bath and 75 ml. of water were added.
• white needles were formed melting at 161l62 C. When this material was dried at C. under vacuum, the melting point was raised to 218220 C.
• Example D Lac!am of 2-(o-carboxyphenyl)thiazolidine
• phthalaldehydic acid (0.11 mole) in 25 ml. ethyl alcohol wasadded to 25 ml. of an aqueous solution of 7.7 g. (0.10 mole) fi-mercaptoethylamine.
• the compounds represented by Formula I (or II) can be used to increase the contrast and raise the maximum density of certain photographic silver halide emulsions. These compounds also have the effect of shortening the toe portion of the characteristic curve.
• the efiect of these compounds is illustrated below with respect to a fine-grained pure silver chloride emulsion.
• This emulsion was prepared using a gelatin derivative, as described in U. S. Patents 2,614,928 and 2,614,931. The emulsion was unripened and unsensitized (chemically or optically) and inert gelatin was used as the vehicle.
• the silver chloride emulsion described above was divided into separate portions and certain of these portions treated with one of the compounds embraced by Formula I or II above, in the amounts indicated in the following table.
• the separate batches of emulsion were then coated on a clear film base and given a 30-second exposure with a 500-watt lamp, 3000 K., in an Eastman Type Ib sensitometer.
• the coatings were then developed for 4 minutes in Eastman Kodak Developer D-1.
• the speed, gamma and fog for each of the coatings were then vmeasured in the manner shown in Examples 5 and 6 of Table A above.
• the maximum density of the coatings was also measured.
• the concentration of the compound of Formula I or II is given on a molar equivalent basis equal to l g. of 4 carboxythiazolidine per mole of silver halide. The results obtained follow:
• the optimum amount of compound to be used as a contrast-increasing agent can "be determined by making the customary tests employed in emulsion making. As indicated above with respect to the fog-inhibiting action of these compounds, the optimum amount will Vary depending upon the presence ,of various emulsion addenda. In general, it has been found that from about .1002 g. to 3.0 g. of compound per'mol. of silver halide is sufficient to provide an optimum amount of contrast increase without serious desensitization. v f
• R represents a member selected from the group consisting of a hydrogen atom and a methyl group
• R represents a member selected from the group consisting of a hydrogen atom, a carboxyl group, and a watersoluble salt of a carboxyl group
• D represents a member selected from the group consisting of an ethylene group and an o-phenylene group
• n represnts a positive integer of from 1 to 2
• Q represents a member selected from the group consisting of an oxygen atom and an imino group.
• w i R' p e e t a m be s eqted' m therer a consisting of a hydrogen atom and a-rnethyl
• group k represents a member selected from the group consisting of a hydrogen atom, a carboxyl group, and a water-soluble salt of a carboxylgroup
• D represents a member selected from the group consisting of an ethylene group and an o-phenylene group
• n represents a positive integer of from 1 to 2
• Q represents a member selected from the group consisting of an oxygen atom and an imino no n 1 .6.
• a photographic :siluer chloride ;emulsion;containing a compound selected from those represented by-ythe" fol- :lowing;general. formula:..
• R represents a jmember selected from the group consisting of a hydrogen atom and a methyl group
• R represents amernber selected from the-group consisting of alayclreg a a em. 1 c h x roup-ma u e -so uble in, D
• D represents an ethylene group and D represents the non-metallic atoms necessary to complete a thiazolidine nucleus.
• D represents an o-phenylene group and D represents the non-metallic atoms necessary to complete a thiazolidine nucleus.
• D represents an ethylene group and D represents the non-metallic atoms necessary to complete a thiazolidine nucleus.
• D represents an o-phenylene group and D represents the non-metallic atoms necessary to complete a thiazolidine nucleus.

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• General Physics & Mathematics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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Citations (4)

• 0
  • BE BE564592D patent/BE564592A/xx unknown
• 1957
  • 1957-02-11 US US639190A patent/US2860985A/en not_active Expired - Lifetime
• 1958
  • 1958-02-06 GB GB3882/58A patent/GB887272A/en not_active Expired
  • 1958-02-07 FR FR1212727D patent/FR1212727A/fr not_active Expired

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