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
  • G03C7/3017—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials with intensification of the image by oxido-reduction
  • G03C7/302—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials with intensification of the image by oxido-reduction using peroxides
• • 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
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/29—Development processes or agents therefor
  • G03C5/305—Additives other than developers
  • G03C5/3053—Tensio-active agents or sequestering agents, e.g. water-softening or wetting agents

Definitions

• This invention relates to photographic developer solutions for use in photographic colour processing and in particular to redox developer solutions.
• Redox (or RX) amplification processes have been described, for example, in British specification Nos 1,268,126, 1,399,481, 1,403,418 and 1,560,572.
• colour materials are developed to produce a silver image (which may contain only small amounts of silver) which then catalyses redox amplification to form a dye image.
• the redox amplifying solution contains a reducing agent, for example a colour developing agent, and an oxidising agent which is more powerful than silver halide and which will oxidise the colour developing agent in the presence of the silver image which acts as the catalyst.
• the oxidised colour developer reacts with a colour coupler (usually contained in the photographic material) to form image dye.
• the amount of dye formed depends on the time of treatment or the availability of colour coupler rather than the amount of silver in the image as is the case in conventional colour development processes.
• a particular application of this technology is in the processing of silver chloride colour paper, especially such paper with low silver levels.
• the amplifying solution contains both an oxidising agent and a reducing agent it is, however, inherently unstable and will decompose on keeping. This instability is catalysed during the processing by the seasoning of species present in the gelatin layer in the photographic material, such as complex transition metal ions such as manganese (Mn) , and/or catechol disulphonate 'CDS 1 , 'TIRON',T .
• complex transition metal ions such as manganese (Mn)
• catechol disulphonate 'CDS 1 , 'TIRON',T In conventional RA-4 type developers this catalytic effect can be substantially reduced or nullified by the addition of one or more sequestering agents which can form a fairly stable soluble complex with the calcium ions or transition metal ions so that the free metal ions, especially ferric ions, are then present in only minute amounts.
• Such sequestering agents may include, for example, a polyacetic acid such as diethylaminetriamine pentaacetic acid 'DTPA 1 or an alkylidene -1,1-diphosphonic acid, such as 1-hydroxy- ethylidene-1,1-diphosphonic acid "HEPA* .
• a polyacetic acid such as diethylaminetriamine pentaacetic acid 'DTPA 1
• an alkylidene -1,1-diphosphonic acid such as 1-hydroxy- ethylidene-1,1-diphosphonic acid "HEPA* .
• a redox-amplification solution comprising hydrogen peroxide or a substance capable of releasing hydrogen peroxide, a reducing agent, such as a colour developing agent, and in combination two or more sequestering agents for complexing with a transition metal ion to inhibit catalysis of impurities emanating from a photographic film coating and enhance the stability of the solution.
• One class of sequestering agent that is present according to the invention is a polyalkylcarboxylic, phosphonic or sulphonic acid containing at least one amine group which has condensed with one or more alkyl hydrogens of the alkylcarboxylic, phosphonic, or sulphonic-acid, which may be represented by the formula (I)
• X 1 and X2 may be the same or different and each is a hydrogen atom, a straight or branched chain alkyl group having
• a, b, c and d are the same or different and each is a hydrogen atom, a straight or branched chain alkyl group having
• X may be repeat units of A or B
• Y is as defined for a, b, c and d or is the group Z or the group B,
• X 3 and X4 are the same or different and are as defined for X 1 and X2 wherein the sum of , n and r is an integer from 1 to 10 and wherein one or both of the hydrogen atoms in each of the (CH2)m. (CH2)n or (CH2)r groups may be replaced by a straight or branched chain alkyl group having 1 to 6 carbon atoms, with the proviso that at least one of X 1, X2, X 3 and X4 is or contains a carboxylic, sulphonyl or phosphonyl group, or a salt thereof.
• Examples of compounds of formula (I) that are particularly suitable are ethylenediaminetetraacetic acid ⁇ DTA', propylenediaminetetraacetic acid 'PDTA', nitrilotetraacetic acid *NTA' but most preferably diethylenetriaminepentaacetic acid 'DTPA', these compounds generally being used in the form of their corresponding tetra- or penta-sodium salts.
• a compound of formula (I) is combined with either an alkylidene-1, 1- diphosphonic acid, such as a compound of formula (II) , as defined hereinbelow and/or a polyhydroxyl phenyl, such as a compound of formula (III) , as defined hereinbelow.
• a compound of formula (II) is defined as
• R 1, R2, R3and R4 are the same or diffe-rent and each is a hydrogen atom, a straight or branched chain alkyl group having 1 to 6 carbon atoms, a hydroxyl, sulphonyl or carboxyl group. and is especially dihydroxyphenyl sulphonate ('catechol' disulphonate » CDS*) or 'TIRO • .
• a redox- amplification solution comprising hydrogen peroxide or a substance capable of releasing hydrogen peroxide, a reducing agent, such as a colour developing agent, and a compound of formula (I) , as hereinbefore defined, or a salt thereof, in combination with either a compound of formula (II) , as hereinbefore defined and/or a compound of formula (III) , as hereinbefore defined, for complexing with a transition metal ion to inhibit catalysis of impurities emanating from a photographic film coating and enhance the stability of the solution.
• a reducing agent such as a colour developing agent
• the redox-amplification solution comprises a compound of formula (I) , or a salt thereof, in combination with both a compound of formula (II) and a compound of formula (III) .
• the redox-amplification solution comprises diethylenetriaminepentaacetic acid, 'DTPA* or a salt thereof and l-hydroxy-ethylidene-1,1- diphosphonic acid, 'HEPA'
• sequestering agents may be combined with the ratio of a y two components being in the range 1:1 to 20:1 by volume, wherein either component may be present in the greater amount.
• Each sequestering agent is added in an amount of from .05ml to lOOml/litre of redox solution, preferably 1ml to 10ml, most preferably 2ml to 6.5ml.
• Compounds capable of releasing hydrogen peroxide include metal peroxides; compounds which include hydrogen peroxide in their crystal structure such as sodium percarbonate; other peroxy compounds such as sodium perborate and persulphate; or soluble organic peroxides, such as butyl peroxide or benzyl peroxide.
• the hydrogen peroxide or a compound such as mentioned above is added in a sufficient quantity to oxidise the colour developing agent in a suitable length of time.
• 30% hydrogen peroxide is used in an amount of from 0.5 to lOOml/litre amplification bath, preferably about 5ml/litre, but equivalent amounts of, for example, 8% or 3% hydrogen peroxide may also be used.
• the reducing agent which is generally a colour developing agent, may be any primary aromatic amine, such as a p-aminophenol or p-phenylenediamine.
• Colour developing agents which can be used include 4-amino-N,N-diethylaniline hydrochloride, 4-amino-3- methyl-N,N-diethylaniline hydrochloride, 4-amino-3- methyl-N-ethyl-N- ⁇ -hydroxyethylaniline sulphate and preferably N-ethyl-N- ⁇ -methanesulphon-amidoethyl-3- methyl-4-aminoaniline (CD3) .
• the reducing agent is added in an amount of from about 1 to 20 g/litre, preferably 2 to 5 g/litre.
• the redox amplification solution preferably has one or more acids, alkalis or buffers , such as an alkali metal carbonate, carbonate/hydrogen carbonate buffer or phosphate buffer to maintain the pH at the required level, which is usually at about pH 10.
• the solution must be well buffered to provide a large reservoir of hydroxyl ions as a hydrogen ion is produced for each atom of metallic silver formed.
• the colour developing agent becomes a more powerful reducing agent with respect to the silver and therefore there is a higher rate of photographic development.
• an anti-oxidant such as diethylhydroxylamine may be used.
• the redox amplification solutions of the present invention may be used with any type of photographic silver halide colour material.
• Such materials and their possible constituents are described, for example, in Research Disclosure Item 308119, December 1989, published by Kenneth Mason Publications, Emsworth, Hants, United Kingdom. However materials based on predominantly silver chloride emulsions are preferred.
• the present invention also provides a method of photographic colour processing including a redox amplification step, which comprises the addition of hydrogen peroxide, or a compound capable of releasing hydrogen peroxide, a reducing agent, such as a colour developing agent, a compound formula (I) , as hereinbefore defined, with either a compound of formula (II) , as hereinbefore defined and/or a compound of formula (III) as hereinbefore defined, for complexing with a transition metal ion to inhibit catalysis of impurities emanating from a photographic film coating and enhance the stability of the solution.
• a redox amplification step which comprises the addition of hydrogen peroxide, or a compound capable of releasing hydrogen peroxide, a reducing agent, such as a colour developing agent, a compound formula (I) , as hereinbefore defined, with either a compound of formula (II) , as hereinbefore defined and/or a compound of formula (III) as hereinbefore defined, for complexing with a transition metal i
• the redox amplification stage may be followed directly by a bleach step or an intermediate stop bath may be employed.
• the photographic material to be processed preferably contains low levels of silver to reduce light scattering and is preferably based on emulsions which comprise at least 80%, preferably at leat 90%, silver chloride and especially substantially pure silver chloride.
• DEVAMP developer-amplifier
• DEVAMP solution is one in which 'DTPA', 'HEPA' .and
• a developer-amplifier of the composition shown in Example 1 was prepared and a solution of each of the following in tap water containing approximately 200ppm of equivalent calcium carbonate prepared and transferred to glass cylinders maintained at 35°C in a water thermostat.
• the 'DTPA' is used in the form of a 40% solution of its penta-sodium salt.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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• 1991
  • 1991-12-03 GB GB919125689A patent/GB9125689D0/en active Pending
• 1992
  • 1992-11-30 DE DE69217557T patent/DE69217557T2/de not_active Expired - Fee Related
  • 1992-11-30 EP EP92924625A patent/EP0615633B1/de not_active Expired - Lifetime
  • 1992-11-30 JP JP5509820A patent/JPH07502131A/ja active Pending
  • 1992-11-30 WO PCT/EP1992/002763 patent/WO1993011460A1/en active IP Right Grant

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