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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/3003—Materials characterised by the use of combinations of photographic compounds known as such, or by a particular location in the photographic element
  • G03C7/3005—Combinations of couplers and photographic additives
  • G03C7/3008—Combinations of couplers having the coupling site in rings of cyclic compounds and photographic additives
  • G03C7/301—Combinations of couplers having the coupling site in pyrazoloazole rings and photographic additives

Definitions

• This invention relates to novel photographic elements and processes employing bicyclic pyrazolo dye-forming couplers which contain a fully substituted carbon at the 6-position and have associated therewith a high-boiling phosphate solvent and a stabilizer.
• Color images are customarily obtained in the photographic art by reaction between an oxidation product of a silver halide developing agent and a dye-forming coupler.
• Pyrazolone couplers are useful for forming magenta dye images; however, such couplers have shortcomings with respect to color reproduction in that the unwanted absorption around 430 nm causes color turbidity.
• Bicyclic pyrazolo couplers particularly pyrazolotriazole couplers, represent another class of couplers for this purpose. Examples of bicyclic pyrazolo couplers are described in, for example, U.S. Patent 4,443,536; U.S. Patent Nos. 1,247,493; 1,252,418; and 1,398,979; and U.S.
• One class of pyrazolotriazole couplers includes 1H-pyrazolo[3,2-c][1,2,4] triazole couplers and another includes 1H-pyrazolo[1,5-b][1,2,4] triazole couplers, such as described in European Patent 177765. While these couplers have a reduced level of unwanted absorption, the conversion of the coupler into an azomethine dye is slow and the maximum attainable density is reduced due to lower coupling efficiency.
• 4,822,730 discloses pyrazolotriazoles having a group expressed by the formula -(A)L-B where L represents -N(R)SO2-, -SO2N(R)-, or -N(R)SO2N(R)-.
• the compounds exemplified contain a methyl or unbranched alkyl group at the 6- position rather than a fully substituted carbon.
• the following compound is suggested: Bicyclic pyrazolo couplers containing a t-butyl group at the 6-position are described in U.S. Patent 4,882,266.
• An example of such a coupler is: Such couplers are not suggested for use in combination with the high-boiling phosphate solvent and stabilizers as described in this invention. Thus the superior light stability achieved by the invention is not realized by this patent.
• European Patent 170,164 suggests the possible conjoint use of a phosphate type solvent with a pyrazoloazole compound to improve light stability but the improvement in stability was insufficient, especially for color prints.
• U. S. Patent 4,900,655 discloses the combination of pyrazolo couplers with high boiling solvents of the nonphosphate type.
• a problem to be solved by this invention is to provide a photographic element and process utilizing the advantageous hue properties of the pyrazolo compounds while attaining sufficient dye light stability.
• the invention provides photographic elements which comprise a support bearing at least one photographic silver halide emulsion layer associated with a dye-forming bicyclic pyrazolo-based coupler, a high-boiling phosphate solvent, a stabilizer, and wherein the coupler has a fully substituted carbon at the 6-position.
• Photographic elements of the invention containing these couplers exhibit improved photographic properties such as increased dye light stability.
• R1 is an alkyl, alkylaryl, arylaryl, or arylalkyl group, substituted or unsubstituted.
• suitable coupler solvents are as follows: Of course it is possible to use mixtures of solvents incorporating the solvent of the invention. It is also to use solvent compounds where all R1 substituents are not identical and where more than one compound coming within the scope of the invention are used conjointly.
• substituent groups for L and T include: an alkyl group which may be straight or branched, and which may be substituted, such as methyl, ethyl, n-propyl, n-butyl, t-butyl, trifluoromethyl, tridecyl or 3-(2,4-di-t-amylphenoxy) propyl; an alkoxy group which may be substituted, such as methoxy or ethoxy; an alkylthio group which may be substituted, such as methylthio or octylthio; an aryl group, an aryloxy group or an arylthio group, each of which may be substituted, such as phenyl, 4-t-butylphenyl, 2,4,6-trimethylphenyl, phenoxy, 2-methylphenoxy, phenylthio or 2-butoxy-5-t-octylphenylthio; a heterocyclic group, a heterocyclic oxy group or a
• L and T together contain from 8 to 22 carbon atoms and most preferrably 12 to 18 carbon atoms.
• the linking group L is a divalent group.
• L may be an alkylene, arylene, or aryloxylene group of from 1 to 20 carbon atoms
• couplers useful in the elements of the invention are examples of substituent groups for the above include: an alkyl group which may be straight or branched, and which may be substituted, such as methyl, ethyl, n-propyl, n-butyl, t-butyl, trifluoromethyl, tridecyl or 3-(2,4-di-t-amylphenoxy) propyl; an alkoxy group which may be substituted, such as methoxy or ethoxy; an alkylthio group which may be substituted, such as methylthio or octylthio; an aryl group, an aryloxy group or an arylthio group, each of which may be substituted, such as phenyl, 4-t-butylphenyl, 2,4,6-trimethylphenyl, phenoxy, 2-methylphenoxy, phenylthio or 2-butoxy-5-t-octylphenylthio; a heterocyclic
• substituent groups include: a carbamoylamino group which may be substituted, such as N-butylcarbamoylamino or N,N-dimethyl-carbamoylamino; an alkoxycarbonylamino group which may be substituted, such as methoxycarbonylamino or tetradecyloxycarbonylamino; an aryloxycarbonylamino group which may be substituted, such as phenoxycaronylamino or 2,4-di-t-butylphenoxycarbonylamino; a sulfonamido group which may be substituted, such as methanesulfonamido or hexadecanesulfonamido; a carbamoyl group which may be substituted, such as N-ethylcarbamoyl or N,N-dibutylcarbamoyl; an acyl group which may be substituted, such as acetyl or
• Substituents for the above substituted groups include halogen, an alkyl group, an aryl group, an aryloxy group, a heterocyclic or a heterocyclic oxy group, cyano, an alkoxy group, an acyloxy group, a carbamoyloxy group, a silyloxy group, a sulfonyloxy group, an acylamino group, an anilino group, a ureido group, an imido group, a sulfonylamino group, a carbamoylamino group, an alkylthio group, an arylthio group, a heterocyclic thio group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonamido group, a carbamoyl group, an acyl group, a sulfamoyl group, a sulfonyl group, a
• the above groups and substituents thereof which contain an alkyl group may include an alkyl group having 1 to 16 carbon atoms.
• the above groups and substituents thereof which contain an aryl group may include an aryl group having 6 to 8 carbon atoms, and the above groups and substituents which contain an alkenyl group may include an alkenyl group having 2 to 6 carbon atoms.
• the bicyclic pyrazolo coupler contains in the coupling position, represented by X in formulae (II) and (IIIA) or (IIIB), may be hydrogen or a coupling-off group also known as a leaving group.
• Coupling-off groups are known to those skilled in the art. Such groups can determine the equivalency of the coupler, can modify the reactivity of the coupler, or can advantageously affect the layer in which the coupler is coated or other layers in the element by performing, after release from the coupler, such functions as development inhibition, development acceleration, bleach inhibition, bleach acceleration, color correction, and the like.
• coupling-off groups include halogen, particularly chlorine, bromine, or fluorine, alkoxy, aryloxy, heterocyclyloxy, heterocyclic, such as hydantoin and pyrazolo groups, sulfonyloxy, acyloxy, carbonamido, imido, acyl, heterocyclylimido, thiocyano, alkylthio, arylthio, heterocyclylthio, sulfonamido, phosphonyloxy and arylazo. They are described in, for example, U.S.
• the coupling-off group is H or halogen, and more preferably, H or Cl.
• L group links T to the pyrazolotriazole core.
• Suitable L groups include the following: wherein: p is an integer of 1-6; m is 0, 1 or 2; R and R', which may be the same or different, each represents a hydrogen atom or a substituent; and Ar represents a substituted or unsubstituted phenylene group (for example, a 1,4-phenylene group, a 1,3-phenylene group, etc.
• Representative Ar groups include the following: preferably, R and R' are independently hydrogen or lower alkyl.
• ballast group is an organic radical of such size and configuration as to confer on the coupler molecule sufficient bulk to render the coupler substantially non-diffusible from the layer in which it is coated in a photographic element.
• groups L R and T from the formula are chosen to meet this criteria as can be determined by one skilled in the art.
• Suitable stabilizers for the photographic elements of this invention include any of those known as effective dye light stabilizers including the following:
• the coupler of this invention can be used in any of the ways and in any of the combinations in which couplers are used in the photographic art.
• the coupler is incorporated in a silver halide emulsion and the emulsion coated on a support to form part of a photographic element.
• the coupler can be incorporated at a location adjacent to the silver halide emulsion where, during development, the coupler will be in reactive association with development products such as oxidized color developing agent.
• the term "associated" signifies that the coupler is in the silver halide emulsion layer or in an adjacent location where, during processing, the coupler is capable of reacting with silver halide development products.
• the photographic elements can be single color elements or multicolor elements.
• Multicolor elements contain dye image-forming units sensitive to each of the three primary regions of the spectrum.
• Each unit can comprise a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum.
• the layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art.
• the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer.
• a typical multicolor photographic element comprises a support bearing a cyan dye image-forming unit comprising at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a magenta dye image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler, and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler, at least one of the couplers in the element being a coupler of this invention.
• the element can contain additional layers, such as filter layers, interlayers, overcoat layers, subbing layers, and the like.
• the photographic element can be used in conjunction with an applied magnetic layer as described in Research Disclosure, November 1992, Item 34390 published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire P010 7DQ, ENGLAND.
• the silver halide emulsions employed in the elements of this invention can be either negative-working or positive-working. Suitable emulsions and their preparation as well as methods of chemical and spectral sensitization are described in Sections I through IV. Color materials and development modifiers are described in Sections V and XXI. Vehicles are described in Section IX, and various additives such as brighteners, antifoggants, stabilizers, light absorbing and scattering materials, hardeners, coating aids, plasticizers, lubricants and matting agents are described , for example, in Sections V, VI, VIII, X, XI, XII, and XVI. Manufacturing methods are described in Sections XIV and XV, other layers and supports in Sections XIII and XVII, processing methods and agents in Sections XIX and XX, and exposure alternatives in Section XVIII.
• Preferred color developing agents are p-phenylenediamines.
• 4-amino N,N-diethylaniline hydrochloride 4-amino-3-methyl-N,N-diethylaniline hydrochloride, 4-amino-3-methyl-N-ethyl-N-(b-(methanesulfonamido) ethyl)aniline sesquisulfate hydrate, 4-amino-3-methyl-N-ethyl-N-(b-hydroxyethyl)aniline sulfate, 4-amino-3-b-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride and 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonic acid.
• negative working silver halide a negative image can be formed.
• positive (or reversal) image can be formed.
• Coupling-off groups are well known in the art. Such groups can determine the equivalency of the coupler, i.e., whether it is a 2-equivalent or a 4-equivalent coupler, or modify the reactivity of the coupler. Such groups can advantageously affect the layer in which the coupler is coated, or other layers in the photographic recording material, by performing, after release from the coupler, functions such as dye formation, development acceleration or inhibition, bleach acceleration or inhibition, electron transfer facilitation, color correction and the like.
• coupling-off groups include chloro, alkoxy, aryloxy, heteroyloxy, sulfonyloxy, acyloxy, acyl, heterocyclyl, sulfonamido, mercaptotetrazole, mercaptopropionic acid, phosphonyloxy anylthio, and arylazo.
• These coupling-off groups are described in the art, for example, in U.S. Pat. Nos. 2,455,169, 3,227,551, 3,432,521, 3,476,563, 3,617,291, 3,880,661, 4,052,212 and 4,134,766; and in U.K. Patents and published application Nos. 1,466,728, 1,531,927, 1,533,039, 2,006,755A and 2,017,704A, the disclosures of which are incorporated herein by reference.
• magenta coupler described herein may be used in combination with other types of magenta image couplers such as 3-acylamino- , 3-anilino-, 5-pyrazolones and heterocyclic couplers (e.g. pyrazoloazoles) such as those described in EP 285,274; U.S. Patent 4,540,654; EP 119,860, or with other 5-pyrazolone couplers containing different ballasts or coupling-off groups such as those described in U.S. Patent 4,301,235; U.S. Patent 4,853,319 and U.S. Patent 4,351,897.
• the coupler may also be used in association with yellow or cyan colored couplers (e.g.
• masking couplers such as those described in EP 213.490; Japanese Published Application 58-172,647; U.S. Patent 2,983,608; German Application DE 2,706,117C; U.K. Patent 1,530,272; Japanese Application A-113935; U.S. Patent 4,070,191 and German Application DE 2,643,965.
• the masking couplers may be shifted or blocked.
• magenta coupler of the invention may be used to replace all or part of the magenta layer image coupler or may be added to one or more of the other layers in a color negative photographic element comprising a support bearing the following layers from top to bottom:
• magenta coupler of the invention may suitably be used to replace all or a part of the magenta coupler in a photographic element such as one comprising a support bearing the following from top to bottom:
• magenta coupler of the invention could be used to replace all or part of the magenta coupler in a photographic element such as one comprising a support and bearing the following layers from top to bottom:
• the couplers may also be used in association with materials that accelerate or otherwise modify the processing steps e.g. of bleaching or fixing to improve the quality of the image.
• Bleach accelerators described in EP 193,389; EP 301,477; U.S. 4,163,669; U.S. 4,865,956; and U.S. 4,923,784 are particularly useful.
• Also contemplated is use of the coupler in association with nucleating agents, development accelerators or their precursors (UK Patent 2,097,140; U.K. Patent 2,131,188); electron transfer agents (U.S. 4,859,578; U.S.
• antifogging and anti color-mixing agents such as derivatives of hydroquinones, aminophenols, amines, gallic acid; catechol; ascorbic acid; hydrazides; sulfonamidophenols; and non color-forming couplers.
• the couplers may also be used in combination with filter dye layers comprising colloidal silver sol or yellow and/or magenta filter dyes, either as oil-in-water dispersions, latex dispersions or as solid particle dispersions. Additionally, they may be used with "smearing" couplers (e.g. as described in U.S. 4,366,237; EP 96,570; U.S. 4,420,556; and U.S. 4,543,323.) Also, the couplers may be blocked or coated in protected form as described, for example, in Japanese Application 61/258,249 or U.S. 5,019,492.
• the coupler may further be used in combination with image-modifying compounds such as "Developer Inhibitor-Releasing” compounds (DIR's).
• DIR's useful in conjunction with the couplers of the invention are known in the art and examples are described in U.S. Patent Nos.
• DIR Couplers for Color Photography
• C.R. Barr J.R. Thirtle and P.W. Vittum in Photographic Science and Engineering , Vol. 13, p. 174 (1969)
• the developer inhibitor-releasing (DIR) couplers include a coupler moiety and an inhibitor coupling-off moiety (IN).
• the inhibitor-releasing couplers may be of the time-delayed type (DIAR couplers) which also include a timing moiety or chemical switch which produces a delayed release of inhibitor.
• inhibitor moieties are: oxazoles, thiazoles, diazoles, triazoles, oxadiazoles, thiadiazoles, oxathiazoles, thiatriazoles, benzotriazoles, tetrazoles, benzimidazoles, indazoles, isoindazoles, mercaptotetrazoles, selenotetrazoles, mercaptobenzothiazoles, selenobenzothiazoles, mercaptobenzoxazoles, selenobenzoxazoles, mercaptobenzimidazoles, selenobenzimidazoles, benzodiazoles, mercaptooxazoles, mercaptothiadiazoles, mercaptothiazoles, mercaptotriazoles, mercaptooxadiazoles, mercaptodiazoles, mercaptooxathiazoles, telleurotetrazoles or benz
• the inhibitor moiety or group is selected from the following formulas: wherein R I is selected from the group consisting of straight and branched alkyls of from 1 to about 8 carbon atoms, benzyl and phenyl groups and said groups containing at least one alkoxy substituent; R II is selected from R I and -SR I ; R III is a straight or branched alkyl group of from 1 to about 5 carbon atoms and m is from 1 to 3; and R IV is selected from the group consisting of hydrogen, halogens and alkoxy, phenyl and carbonamido groups, -COOR V and -NHCOOR V wherein R V is selected from substituted and unsubstituted alkyl and aryl groups.
• the coupler moiety included in the developer inhibitor-releasing coupler forms an image dye corresponding to the layer in which it is located, it may also form a different color as one associated with a different film layer. It may also be useful that the coupler moiety included in the developer inhibitor-releasing coupler forms colorless products and/or products that wash out of the photographic material during processing (so-called "universal" couplers).
• the developer inhibitor-releasing coupler may include a timing group which produces the time-delayed release of the inhibitor group such as groups utilizing the cleavage reaction of a hemiacetal (U.S. 4,146,396, Japanese Applications 60-249148; 60-249149); groups using an intramolecular nucleophilic substitution reaction (U.S. 4,248,962); groups utilizing an electron transfer reaction along a conjugated system (U.S. 4,409,323; 4,421,845; Japanese Applications 57-188035; 58-98728; 58-209736; 58-209738) groups utilizing ester hydrolysis (German Patent Application (OLS) No.
• a timing group which produces the time-delayed release of the inhibitor group such as groups utilizing the cleavage reaction of a hemiacetal (U.S. 4,146,396, Japanese Applications 60-249148; 60-249149); groups using an intramolecular nucleophilic substitution reaction (U.S. 4,248,962); groups utilizing an electron
• timing group or moiety is of one of the formulas: wherein IN is the inhibitor moiety, Z is selected from the group consisting of nitro, cyano, alkylsulfonyl; sulfamoyl (-SO2NR2); and sulfonamido (-NRSO2R) groups; n is 0 or 1; and R VI is selected from the group consisting of substituted and unsubstituted alkyl and phenyl groups.
• the oxygen atom of each timing group is bonded to the coupling-off position of the respective coupler moiety of the DIAR.
• Suitable developer inhibitor-releasing couplers for use in the present invention include, but are not limited to, the following: It is also contemplated that the concepts of the present invention may be employed to obtain reflection color prints as described in Research Disclosure , November 1979, Item 18716, available from Kenneth Mason Publications, Ltd, Dudley Annex, 12a North Street, Emsworth, Hampshire P0101 7DQ, England, incorporated herein by reference. Materials of the invention may be coated on pH adjusted support as described in U.S. 4,917,994; with epoxy solvents (EP 0 164 961); with nickel complex stabilizers (U.S. 4,346,165; U.S. 4,540,653 and U.S.
• ballasted chelating agents such as those in U.S. 4,994,359 to reduce sensitivity to polyvalent cations such as calcium
• stain reducing compounds such as described in U.S. 5,068,171 and U.S. 5,096,805.
• the average useful ECD of photographic emulsions can range up to about 10 microns, although in practice emulsion ECD's seldom exceed about 4 microns. Since both photographic speed and granularity increase with increasing ECD's, it is generally preferred to employ the smallest tabular grain ECD's compatible with achieving aim speed requirements.
• Emulsion tabularity increases markedly with reductions in tabular grain thickness. It is generally preferred that aim tabular grain projected areas be satisfied by thin (t ⁇ 0.2 micron) tabular grains. To achieve the lowest levels of granularity it is preferred that aim tabular grain projected areas be satisfied with ultrathin (t ⁇ 0.06 micron) tabular grains. Tabular grain thicknesses typically range down to about 0.02 micron. However, still lower tabular grain thicknesses are contemplated. For example, Daubendiek et al U.S. Patent 4,672,027 reports a 3 mole percent iodide tabular grain silver bromoiodide emulsion having a grain thickness of 0.017 micron.
• tabular grains of less than the specified thickness account for at least 50 percent of the total grain projected area of the emulsion.
• tabular grains satisfying the stated thickness criterion account for the highest conveniently attainable percentage of the total grain projected area of the emulsion.
• tabular grains satisfying the stated thickness criteria above account for at least 70 percent of the total grain projected area.
• tabular grains satisfying the thickness criteria above account for at least 90 percent of total grain projected area.
• Suitable tabular grain emulsions can be selected from among a variety of conventional teachings, such as those of the following: Research Disclosure, Item 22534, January 1983, published by Kenneth Mason Publications, Ltd., Emsworth, Hampshire P010 7DD, England; U.S. Patent Nos.
• the emulsions can be surface-sensitive emulsions, i.e., emulsions that form latent images primarily on the surfaces of the silver halide grains, or internal latent images predominantly in the interior of the silver halide grains.
• the emulsions can be negative-working emulsions, such as surface-sensitive emulsions or unfogged internal latent image-forming emulsions, or direct-positive emulsions of the unfogged, internal latent image-forming type, which are positive-working when development is conducted with uniform light exposure or in the presence of a nucleating agent.
• Photographic elements can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image and then processed to form a visible dye image.
• Processing to form a visible dye image includes the step of contacting the element with a color developing agent to reduce developable silver halide and oxidize the color developing agent. Oxidized color developing agent in turn reacts with the coupler to yield a dye.
• the processing step described above provides a negative image.
• the described elements can be processed in the known C-41 color process as described in, for example, the British Journal of Photography Annual of 1982, pages 209 - 211 and 1988, pages 191-198 or in known processes for processing color photographic papers, such as the known RA-4 process of Eastman Kodak Company.
• the described elements are optionally processed in the known color processes for processing color print papers, such as the processes described in the British Journal of Photography Annual of 1988, pages 198-199.
• the color development step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, and then uniformly fogging the element to render unexposed silver halide, but not form dye, and then uniformly fogging the element to render unexposed silver halide developable.
• a direct positive emulsion can be employed to obtain a positive image.
• Pyrazolotriazole couplers as described are prepared by general methods of synthesis described in the art, such as in U.S. Patent No. 4,540,654.
• An illustrative scheme is as follows:
• Dispersions of the couplers were prepared in the following manner: The quantities of each component are found in Table I.
• coupler solvent and ethyl acetate were combined and warmed to dissolve.
• gelatin, Alkanol XCTM surfactant and Trademark of E. I. DuPont Co., USA
• water were combined and warmed to about 40°C.
• the two mixtures were mixed together and passed three times through a Gaulin colloid mill.
• the ethyl acetate was removed by evaporation and water was added to restore the original weight after milling.
• the photographic elements were prepared by coating the following layers in the order listed on a resin-coated paper support:
• the photographic elements were given stepwise exposures to green light and processed as follows at 35°C: Developer 45 seconds Bleach-Fix 45 seconds Wash (running water) 90 seconds
• the developer and bleach-fix were of the following compositions:
• Triethanolamine 12.41 g Blankophor REUTM (Mobay Corp.) 2.30 g Lithium polystyrene sulfonate (30%) 0.30 g N,N-Diethylhydroxylamine (85%) 5.40 g Lithium sulfate 2.70 g N- ⁇ 2-[(4-amino-3-methylphenyl)ethylamino] ethyl ⁇ -methanesulfonamide, sesquisulfate 5.00 g 1-Hydroxyethyl-1,1-diphosphonic acid (60%) 0.81 g Potassium carbonate, anhydrous 21.16 g Potassium chloride 1.60 g Potassium bromide 7.00 g Water to make 1.00 L pH @ 26.7°C adjusted to 10.4 +/- 0.05
• Magenta dyes were formed upon processing.
• the processed coatings were then illuminated by simulated daylight at 50 klux for periods of 2,4, and 6 weeks.
• the green densities were monitored and the time in weeks required for 30% density loss from an initial density of 1.0 (T30) was calculated.
• T30 initial density of 1.0

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  • 1993-12-13 JP JP31154293A patent/JPH06222530A/ja active Pending
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