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
  • G03C7/305—Substances liberating photographically active agents, e.g. development-inhibiting releasing couplers
  • G03C7/30541—Substances liberating photographically active agents, e.g. development-inhibiting releasing couplers characterised by the released group
• • 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
  • G03C7/305—Substances liberating photographically active agents, e.g. development-inhibiting releasing couplers
  • G03C7/30576—Substances liberating photographically active agents, e.g. development-inhibiting releasing couplers characterised by the linking group between the releasing and the released groups, e.g. time-groups
• • 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
  • G03C7/305—Substances liberating photographically active agents, e.g. development-inhibiting releasing couplers
  • G03C7/30594—Combination of substances liberating photographically active agents

Definitions

• This invention relates to new photographic couplers, such as naptholic and acylanilide couplers, that are capable of forming washout dyes and releasing bleach accelerator groups in a photographic material upon photographic processing for formation of an improved image and to a photographic material and process using such compounds.
• a photographically useful group (PUG) from a compound, such as a photographic coupler, in a photographic material and process.
• PAG photographically useful group
• U.S. Patents 4,248,962; 4,409,323 and 4,861,701 describes groups that enable timed release of a photographically useful group.
• Bleach accelerator groups have also been used as coupling-off groups, such as described in European Patent Specification No. 193389 and U.S. Patents 4,861,701; 4,959,299 and 4,912,024.
• the part of the compound that remains in the photographic material after release of the coupling-off groups and the dye that is formed in the material from the reaction with oxidized developer often provide undesired properties in the photographic material during or after photographic processing.
• the dye formed from a coupler upon release of the coupling-off group often adversely affects the desired image.
• One answer to this problem has been to provide a water-solubilizing group on the parent coupler to enable the dye formed from the coupler to be washed out of the photographic element upon photographic processing.
• Such couplers are described in, for example, U.S. Patents 4,482,629 and 5,026,628.
• a class of washout couplers (couplers capable of forming dyes that may be washed out of photographic materials containing such couplers upon photographic processing) that are especially useful is the naphtholic class of couplers, such as described in U.S. Patents 4,482,629 and 5,026,62.
• couplers have not provided both enabling of washout of the dye formed and bleach acceleration upon processing of the photographic material containing such a coupler.
• DIR's development inhibitor releasing couplers
• the present invention solves these problems by providing a color photographic element comprising a support bearing at least one photographic silver halide emulsion layer, an image dye-forming coupler, and a combination of a development inhibitor releasing coupler, (DIR), and a bleach accelerating releasing washout coupler, (BARC), the bleach accelerating releasing washout coupler (A)
• the development inhibitor releasing coupler is selected from a timed and non-timed development inhibitor releasing coupler (B).
• Couplers of the invention can be coated in imaging layers, non-imaging layers or interlayers.
• Non-imaging layers or interlayers can contain interlayer scavengers, filter dyes of any type known in the photographic art including solid particle dispersion, conventional oil-in water dispersed filter dyes and washout filter dyes, non-imaging silver emulsions such as fine particle Carey-Lea or Lippmann emulsion containing layers, or yellow colored silver emulsions which are non-imaging layers.
• the interlayers can be located between imaging layers, between non-imaging layers, between an imaging and an non-imaging layer, between an antihalation layer and an interlayer or between an antihalation and an imaging layer.
• said couplers behave as photographic scavengers, forming washout dyes, and preventing excess oxidized color developer from diffusing to another imaging layer.
• these couplers can affect the development inhibition of the silver halide in not only the layer in which it is coated but also in adjacent layers thus allowing for the use of increased amounts of development inhibiting releasing compounds in photographic elements, resulting in increased sharpness.
• one particular advantage of locating said couplers in an interlayer is to minimize any speed loss due to direct competition of oxidized color developer for said couplers over the imaging couplers.
• the coupler moiety can be any coupler moiety that enables formation of a dye during photographic processing that can be washed out of the photographic material containing such a coupler.
• a preferred COUP is a naphtholic coupler moiety containing a water solubilizing group, in the 2-position of the naphtholic coupler moiety. Any water solubilizing group known in the photographic art is useful. Preferred water solubilizing groups include carboxyl, sulfo, hydroxyl, sulfonamido, carbonamido, sulfamoyl, carbamoyl and salts thereof. Amide groups such as -CONH2 and CONHCH3 are especially useful.
• a preferred coupler (A) is a naphtholic coupler comprising a water solubilizing group in the 2-position and represented by the formula: wherein: (R1) y -BLEACH is a coupling-off group wherein R1 is selected from a timing group and a releasing group; BLEACH is a bleach accelerator group; y is 1 or 2; R4 can be selected from hydrogen, or a substituent such as -Cl, -NO2, -OCH3, -NHSO2R5, -NHCOR5, -SO2NHR5, -CONHR5, -CO2R5, or -COR5 and which does not adversely affect the release of (R1)y-BLEACH from COUP; R3 and R5 is selected from the group consisting of hydrogen, substituted or unsubstituted alkyl containing 1-5 carbon atoms and substituted or unsubstituted aryl containing 6-8 carbon atoms wherein the substituted or unsubstituted alkyl or aryl is
• a preferred R1 group is selected from the group consisting of: wherein: Q is selected from O (oxygen), S (sulfur), or N (nitrogen); R6 and R10 is hydrogen or a substituent selected from substituted or unsubstituted alkyl and substituted or unsubstituted aryl, nitro, hydrogen, amino, substituted amino, carboxylic acid, sulfonic acid, methoxy, chloro, bromo, ester groups such as -CO2CH3, keto groups such as -COCH3, or -NHCOCH3, -CONHCH3, -NHSO2CH3, or -SO2NHCH3; R7, R8, R11, and R12 are selected from hydrogen, substituted or unsubstituted alkyl, and substituted or unsubstituted aryl; R9 is unsubstituted or substituted alkyl or substituted or unsubstituted aryl; Z1 represents the atoms necessary to complete a 5 or 6 member aryl or hetero
• R1 groups useful in the invention are described in U.S. Patent 4,886,736 incorporated herein by reference. Specific R1 groups can be found at Col. 16, line 50 through Col. 21 and preferably contains a ballast.
• a further preferred coupler (A) is a naphtholic coupler selected from the group having the following formula: wherein: R3 through R12, w, n, Q, and Z1 are as defined previously.
• BLEACH as referred to herein can be represented by the formula: -S-R13-R14 wherein: R13 is an unsubstituted or substituted alkylene containing 1 to 8 carbon atoms; and R14 is a water solubilizing group.
• R14 groups are examples of useful water solublizing groups: -CO2H -NHSO2CH3 -NHCO2CH3 -NHCO2C2H5 -SO3H -OH -SO2NH2 -NR 14a R 14b wherein: R 14a is hydrogen or alkyl of 1 to 4 carbon atoms, R 14b is alkyl of 1 to 4 carbon atoms and wherein at least one of R 14a and R 14b is alkyl and the total carbons in R 14a and R 14b is no more than 8. R 14a and R 14b together can form a ring.
• Preferred couplers (A) are represented by the structures denoted as: B-2, B-3, B-4, B-13, B-14, B-15, B-16, B-17, B-18, B-19, B-20 and B-24.
• the development inhibiting releasing coupler (B) may be selected from: wherein: INH is a photographic development inhibiting group; COUP is a coupler moiety; BALLAST is a photographic ballast; Q is selected from O (oxygen), S (sulfur), or N (nitrogen); R6 and R10 is hydrogen or a substituent selected from substituted or unsubstituted alkyl and substituted or unsubstituted aryl, nitro, amino, substituted amino, carboxylic acid, sulfonic acid, methoxy, chloro, bromo, ester groups such as - CO2CH3, keto groups such as -COCH3, or -NHCOCH3, - CONHCH3, -NHSO2CH3, or -SO2NHCH3; R7, R8, R11, and R12 are selected from hydrogen, substituted or unsubstituted alkyl, and substituted or unsubstituted aryl; R9 is unsubstituted or substituted alkyl or substituted or
• INH can be any releasable development inhibitor group.
• Typical INH groups are described in, for example U.S. Patents 4,477,563; 4,782,012; 4,886,736; 4,912,024; 4,959,299; and 5,026,628; the disclosures of which are incorporated herein by reference.
• Preferred development inhibitor groups are heterocyclic inhibitor groups which for example, include mercaptotetrazoles, mercaptoxadiazoles, mercaptothiadiazoles and benzotriazoles. Structures A-1 through A-8 as follows, represent typical releasable development inhibitor groups.
• R b , R e , R h , and R i are individually hydrogen, substituted or unsubstituted alkyl of 1 to 8 carbon atoms such as methyl, ethyl, propyl, butyl, 1-ethylpentyl, 2-ethoxyethyl, substituted phenyl, unsubstituted phenyl; substituted or unsubstituted phenyl of 6 to 10 carbon atoms; alkylthio, such as methyl, ethyl, propyl, butyl or octylthio; or alkyl esters such as -CO2CH3, -CO2C2H5, -CO2C3H7, -CO2C4H9, - CH2CO2CH3, -CH2CO2C2H5, -CH2CO2C3H7, -CH2CO2C4H9, - CH2CH2CO2CH3, -CH2CH2CO2C
• the photographic couplers of the invention can be incorporated in photographic elements by means and precesses known in the photographic art. In a photographic element prior to exposure and processing the photographic coupler should be of such size and configuration that it will not diffuse through the photographic layers.
• the coupling off group as described can be any group or combination of groups that is releasable during photographic processing and enables release, with or without time delay, of BLEACH, a bleach accelerator group, used in the acceleration of bleaching of silver in the photographic material.
• BLEACH a bleach accelerator group
• Especially useful coupling-off groups are described in U.S. Patents 4,912,024; 4,959,299 and European Patent Specification No. 193389, the disclosures of which are incorporated herein by reference.
• coupler refers to the entire compound including the coupler moiety and the coupling-off group.
• coupler moiety herein refers to that portion of the compound other than the coupling-off group.
• the timing groups as described, when such a group is employed in the coupling-off group, can be any timing group or combination of timing groups known in the photographic art. Such timing groups enable tailoring of the timing of release of the bleach accelerator group at the appropriate time and place.
• Useful timing groups are described in, for eample, U.S. Patents 4,959,299; 4.861.701; 4,912,024; 4,409,323; and 4,248,962 and European Patent Specification No. 193389, the disclosures of which are incorporated herein by reference.
• the releasing groups as described when such a group is employed in the coupling-off group, can be any releasing group or combination of releasing groups known in the photographic art. Such releasing groups differ from the described timing groups in that the releasing groups do not provide a significant time delay in the release of a contiguous or adjacent group.
• the water solubilizing group (SOL) can be any water solubilizing group known in the photographic art to enable wash-out of the dye formed in photographic processing from the compound (A).
• Typical watersolublizing groups include groups terminated with an acid group, such as carboxy, sulfo or hydroxy which may also form a salt and other groups described in U.S. Patent 4,482,629 (col. 4, lines 1-3) or an amide group.
• the compound (A) can have one or more water-solubilizing groups. The number and type of water-solubilizing groups should not be sufficient to make the compound (A) mobile in the photographic element prior to exposure and processing.
• the (R1)y-BLEACH can also contain one or more water-solubilizing groups if desired.
• a typical water-solubilizing group is carbonamido group -CONHR a wherein R a is hydrogen or an alkyl group containing 1 to 3 carbon atoms, preferably -CONHCH3 or -CONHC2H5; or a group containing a water-solubilizing group, such as carboxy, sulfo or hydroxy groups, for instance, -CONH2CH2CH2OH, -CONH2CH2CO2H, or -CONH2CH2CH2CO2H.
• Such a group can be, for example, in the 2-position of the naphtholic coupler.
• coupler (A) cleaves the bond between the coupling-off group and the coupler moiety of the coupler (A). Tailoring of the particular parts of the releasing groups and timing groups as required for a given releasable bleach accelerator group allows control over the timing and rate of the release of the bleach accelerator group.
• the releasing group and/or timing groups can contain a ballast group, BALLAST, if desired.
• BALLAST is a ballast group that is known in the photographic art.
• the ballast group as described is an organic group of such size and configuration as to confer on the molecule sufficient bulk to render the molecule substantially non-diffusible from the layer in which it is coated in a photographic element.
• Representative ballast groups include substituted or unsubstituted alkyl or aryl groups typically containing 8 to 40 carbon atoms.
• a process of forming an image having the described advantages comprises developing an exposed photographic element by means of a color developing agent in the presence of described coupler (A).
• the naphtholic coupler moiety can be ballasted or unballasted provided that the dye formed upon oxidative coupling is capable of being washed out of the photographic element. It can be monomeric, or it can be part of a dimeric, oligomeric or polymeric coupler, in which case more than one group containing the bleach accelerator group can be contained in the coupler, or it can form part of a bis compound in which the bleach accelerator group forms part of a link between two coupler moieties.
• the photographic element can comprise other couplers known in the photographic art.
• the photographic element can, for example comprise at least one photographic coupler that is capable of release during photographic processing a reagent or a photographic dye.
• a photographic reagent herein is a moiety that upon release further reacts with components in the photographic element, such as a development inhibitor, a development accelerator, a bleach inhibitor, a bleach accelerator, a coupler (for example, a competing coupler, a dye-forming coupler, or a development inhibitor releasing coupler (DIR coupler), a dye precursor, a dye, a developing agent (for example, a competing developing agent, a dye-forming developing agent, or a silver halide developing agent), a silver complexing agent, a fixing agent, an image toner, a stabilizer, a hardener, a tanning agent, a fogging agent, an ultraviolet radiation absorber, an antifoggant, a nucleator, a chemical or spectral sensitizer or desensitizer.
• the bleach accelerator group can be present in the coupling-off group as a preformed species or it can be present in a blocked form or as a precursor.
• the bleach accelerator group can be for example a preformed bleach accelerator group or the bleach accelerator function can be blocked.
• the naphtholic couplers of the invention are especially useful in combination with at least one development inhibitor releasing coupler (DIR couplers) known in the photographic art.
• DIR couplers development inhibitor releasing coupler
• the photographic couplers of the invention can be incorporated in photographic elements by means and processes known in the photographic art. In a photographic element prior to exposure and processing the photographic coupler should be of such size and configuration that it will not diffuse through the photographic layers.
• Photographic elements of this invention can be processed by conventional techniques in which color forming couplers and color developing agents are incorporated in separate processing solutions or compositions or in the element.
• Photographic elements in which the compounds of this invention are incorporated can be a simple element comprising a support and a single silver halide emulsion layer or they can be multilayer, multicolor elements.
• the compounds of this invention can be incorporated in at least one of the silver halide emulsion layers and/or in at least one other layer, such as an adjacent layer, where they will come into reactive association with oxidized color developing agent which has developed silver halide in the emulsion layer.
• the silver halide emulsion layer can contain or have associated with it, other photographic coupler compounds, such as dye-forming couplers, colored masking couplers, and/or competing couplers. These other photographic couplers can form dyes of the same or different color and hue as the photographic couplers of this invention.
• the silver halide emulsion layers and other layers of the photographic element can contain addenda conventionally contained in such layers.
• a typical multilayer, multicolor photographic element can comprise a support having thereon a red-sensitive silver halide emulsion unit having associated therewith a cyan dye image-providing material, a green-sensitive silver halide emulsion unit having associated therewith a magenta dye image-providing material and a blue-sensitive silver halide emulsion unit having associated therewith a yellow dye image-providing material, at least one of the silver halide emulsion units having associated there with a photographic coupler of the invention.
• Each silver halide emulsion unit can be composed of one or more layers and the various units and layers can be arranged in different locations with respect to one another.
• the light sensitive silver halide emulsions can include coarse, regular or fine grain silver halide crystals or mixtures thereof and can be comprised of such silver halides as silver chloride, silver bromide, silver bromoiodide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide and mixtures thereof.
• the emulsions can be negative-working or direct-positive emulsions. They can form, latent images predominantly on the surface of the silver halide grains or predominantly on the interior of the silver halide grains. They can be chemically and spectrally sensitized.
• the emulsions typically will be gelatin emulsions although other hydrophilic colloids are useful. Tabular grain light sensitive silver halides are particularly useful such as described in Research Disclosure , January 1983, Item No. 22534, and U.S. Patent 4,434,226.
• the support can be any support used with photographic elements. Typical supports include cellulose nitrate film, cellulose acetate film, polyvinylacetal film, polyethylene terephthalate film, polycarbonate film and related films or resinous materials as well as glass, paper, metal and the like. Typically, a flexible support is employed, such as a polymeric film or paper support. Paper supports can be acetylated or coated with baryta and/or an a-olefin polymer, particularly a polymer of an a-olefin containing 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene-butene copolymers and the like.
• the coupler (A) can be used in photographic elements in the same way as photographic couplers which release bleach accelerator groups have previously been used in photographic elements.
• the couplers can be incorporated in a photographic element for different purposes and in different locations.
• the photographic elements can be coated on a variety of supports as described in Research Disclosure Section XVII and the references described therein.
• Photographic elements can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image as described in Research Disclosure Section XVIII and then processed to form a visible dye image as described in Research Disclosure Section XIX.
• 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.
• Preferred color developing agents useful in the invention are p-phenylene diamines.
• the processing step described above gives a negative image.
• this step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form a 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.
• Compounds of the invention can be prepared by two routes, A and B as follows:
• route A Scheme 1
• the BLEACH G-1 is reacted with phosgene to form the thiochloroformate G-2 which is then reacted with the alcohol group of coupler G-3, in the presence of a weak base to give compounds of the invention, G-4.
• G-4 contains an ester group on R14, or another blocked solublizing group, an additional final step is necessary to form the free solublizing group. Examples of the synthesis of compounds of the invention using route A are given for B-1, B-7 and B-8.
• Phenyl-1,4-dihydroxy-2-naphthoate (100g, 356.78mMol) was dissolved in deoxygenated tetrahydrofuran, (500mL) and deoxygenated methanol, (500mL) added. To this solution, stirred at room temperature under a nitrogen atmosphere, was added ammonium acetate, (50.0g, 648.63mMol) followed by concentrated ammonium hydroxide, (1.0L). After stirring for 3hr. the reaction solution was then poured into ice-cold 2N-HCl, (4.0L) and enough concentrated HCl added to bring the pH to 1. The resulting product, Compound (1), was filtered off, washed well with water and air-dried. The crude product was washed with dichloromethane and air-dried again. Yield: 62.0 g (72%).
• Methyl 3-thiopropionate (11.5mL, 0.104mMol) was dissolved in tetrahydrofuran, (100mL) and the solution cooled to 0°C. A 20%- solution of phosgene in toluene, (205mL, 0.415Mol) was added in a steady stream, whereupon the temperature rose to approximately 10°C. After the phosgene had been added the cooling bath was removed and the reaction stirred for 8hrs. and let warm to room temperature. At the end of this period the solvent and excess phosgene were removed under reduced pressure and the residual viscous liquid co-evaporated with dichloromethane, (X3). The product, methyl 3[(chlorocarbonyl)thiol]propionate, (6) so obtained was used directly in the next step.
• B-1 was generated from compound (9) on treating (9) with concentrated hydrochloric acid in acetic similar to the generation of B-1 from compound (7).
• Invention compound B-8 was prepared from compound (8) (8.2mMol), 2-thioethanol (1.7mL, 24.5mMol) and N,N-diisopropylethylamine (4.2mL, 24.5mMol) in tetrahydrofuran (30mL) in a similar manner to that described for compound (9) route B.
• the product was purified by pressure chromatography over silica gel with 40% ethyl acetate in heptane as solvent to give B-8 as a foam. Yield 3.5g, 60%.
• the H1-nmr and mass spectrum were identical to that of B-8 formed via route A.
• Photographic elements were prepared comprising the bleach accelerating releasing couplers (BARCs) forming washout dyes as described.
• Couplers Structures of the couplers are as follows: Strips of each element were exposed to red light through a graduated density step tablet and then developed 3.25 minutes at 40°C in color developer solution CDs1, stopped, washed, bleached using bleach solutions Bls1, Bls1 modified as described, or Bls2, fixed, washed and dried. Bleach solutions referred to should not be confused with the earlier BLEACH which is a fragment released from coupler (A). The residual silver levels were measured by X-ray fluoresence.
• Color Developer, CDs1 Distilled Water 800mL Sodium Metabisulfite 2.78 g Sodium Sulfite, anhydrous 0.38 g Kodak CD-4 (color developer)* 4.52 g Potassium Carbonate, anhyd.
• Bleach Solution Bls1 Distilled water 600mL Ammonium bromide 150g Ammonium Ferric EDTA (1.56M, pH 7.05, 44% by weight. Contains 10% molar excess EDTA, 3.5% by weight 175mL Glacial acetic acid 9.5mL Sodium nitrate 35g Distilled water to 1L pH at 26.7°C 6.00 +/-0.05 Adjusted with NH4OH or HNO3.
• Bleach Solution, Bls2 Gelatin 0.5g Sodium persulfate 33.0g Sodium chloride 15.0g Sodium dihydrogen phosphate (anhydrous) 9.0g Distilled water to 1L Structures of the couplers are as follows:
• Example 1 Table 1, it can be seen that compounds of the invention B-1 and B-2, release a bleaching fragment which gives desired bleaching and contrast increases without undesired large speed increases observed with comparison compound Cm-1.
• the large speed increase associated with Cm-1 is due to the formation of cyan dye which does not wash out of the element.
• Table 1 also shows two variations in bleaching fragment both of which contain a carboxylic acid group, released from B-3 and B-4. Both give the desired increases in contrast and bleaching performance similar to B-1 and B-2. They do not show the large speed increases associated with the comparison compound Cm-1.
• Table 1 shows two variations in bleaching fragment containing different amine groups and released from B-5 and B-6.
• amine containing bleaching fragments are more effective at promoting bleaching than carboxylic acid containing bleaching fragments.
• B-5 and B-6 provide effective contrast increases and bleaching performance without the disadvantages associated with the non-washout nature of the dye formed from Cm-2.
• Table 2 also shows that photographic elements containing compounds of the invention have lower D min values than those containing S-1. This shows that compounds of the invention are very effective scavangers of oxidized color developer.
• Compounds of the invention give excellent bleaching when coated in interlayers.

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  • 1993-06-23 EP EP19930201812 patent/EP0577192B1/de not_active Expired - Lifetime
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