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
  • G03C7/407—Development processes or agents therefor
  • G03C7/413—Developers

Definitions

• a photographic color developer mixture which contains a color developer of the p-phenylene diamine series and a water softener of the aminopolycarboxylic acid series and in addition a water-soluble aromatic polyhydroxy compound having at least two hydroxyl groups in orthoposition to each other, has improved stability to atmospheric oxygen and does not deposit chalky precipitates.
• the invention relates to an aqueous alkaline developer mixture for the production of coloured photographic images and with improved resistance to oxidation.
• the water softeners mainly used are polyphosphates, e.g. sodium hexametaphosphate, or carboxylic acids which contain amino groups, e.g. ethylene diaminotetracetic acid.
• polyphosphates e.g. sodium hexametaphosphate
• carboxylic acids which contain amino groups, e.g. ethylene diaminotetracetic acid.
• the effectiveness of these compounds depends to a large extent on the composition of the developer.
• black-andwhite developers for example, water softeners from either of the two classes of compounds mentioned above may be used.
• Considerable difiiculties arise in the case of colour photographic developers.
• Sodium hexametaphosphate for example, is no longer satisfactory for modern high speed development processes which are carried out at elevated temperatures, and precipitates which contain calcium are formed within a fairly short time.
• ethylene diaminotetracetic acid is an excellent sequestering agent even for colour photographic developers, its usefulness is limited by the fact that it considerably reduces the stability of colour photographic developers. This effect is presumably due to accelerated decomposition of the substances which are added to improve the resistance to oxidation, e.g. hydroxylamine.
• aqueous alkaline developer mixture for the production of colour photographic images which contains a colour developer of the p-phenylene diamine series and a water softener of the aminopolycarboxylic acid series and in particular ethylene diaminotetracetic acid has now been found which contains in addition a water-soluble aromatic polyhydroxyl compound which has two hydroxyl groups in other-position to each other.
• o-dihydroxy compounds of the benzene or naphthalene series e.g. pyrocatechol, pyrocatechol-3,S-disulphonic acid, pyrogallol, gallic acid or 2,3-dihydroxy naphthalene-6-sulphonic acid.
• Sulpho-substituted or carboxyl-substituted compounds are especially suitable because they have the required solubility in water.
• the compounds to be used according to the invention must, of course, be photographically inert at the concentrations at which they are used and, in particular, they must not interfere with chromogenic development.
• the concentration of the dihydroxy compounds in the colour developers according to the invention may vary within wide limits. It depends on the nature of the developer, the required effect and on the properties of the dihydroxy compounds. Concentrations of from 1 to 400 mg. per litre and preferably of from 1 to 200 mg. per litre have generally been found to give the best results. This depends largely on the molecular weight of the dihydroxy compound used.
• the colour developers according to the invention may also contain the usual additives.
• Suitable colour developer substances of the p-phenylene diamine series N,N-diethyl-p-phenylene diamine, N-ethyl-N-fl-hydroxyethyl-p-phenylene diamine, N-butyl-N-w-sulphobutyl-p-phenylene diamine, N-ethyl-N-methylsulphonylaminoethyl-p-phenylene diamine and 4-amino-3-methyldiethyl aniline.
• the alkalis used may be sodium or potassium carbonate, sodium borate, sodium phosphate or sodium or potassium hydroxide.
• the mixtures contain the usual antioxidants, e.g. hydroxylamine salts or alkali metal sulphites.
• Developer 1 4 g. of sodium hexametaphosphate.
• Developer 2 4 g. of the sodium salt of ethylene diaminotetracetic acid.
• developer 2 As regards the developer substance is clear from the above table. Whereas in developer 3 according to the invention the concentration of developer substance is unchanged and in developer 1 it is only slightly changed, the quantity of developer substance has dropped almost to half in developer 2.
• Developers 1 and 3 provide colour wedges with the same step number and same density in the fresh state and after 48 hours aeration, whereas in the case of developer 2 the images obtained after 48 hours aeration have a much flatter gradation than those obtained with the fresh developer.
• developer 1 The quality of developer 1 is photographically satisfactory but if this developer is used in a developer apparatus which is operated at an elevated temperature, the developer becomes cloudy due to precipitated calcium compounds after only a few days and solid deposits are formed at the bottom of the development vessel and in the pipes.
• Developer 4 4 g. of sodium hexametaphosphate.
• Developer 5 4 g. of the sodium salt of ethylene diaminotetracetic acid.
• Developer 6 The same as in developer 5 plus 0.025 g. of pyrocatechol-3,5-disulphonic acid.
• the gradation is determined from the resulting wedges. The results obtained agree with the analytical results. Whereas in the case of developers 4 and 6 no difierence can be detected between the freshly prepared developer mixtures and the aerated mixtures, the treated developer bath 5 brings about a strongly flattened gradation.
• EXAMPLE 3 A colour developer mixture is prepared in water having 15 German degrees of hardness and an iron content of 0.3 mg./l., using a colour developer substance, the sodium salt of ethylene diaminotetracetic acid as water softener and various aromatic o-dihydroxy compounds to increase the stability of the developer.
• Ethylene diaminotetracetic acid in the form of the tetrasodium salt 1.2 Hydroxylamine sulphate 4 Sodium sulphite sicc 4 Potassium carbonate Potassium bromide 1 N-butyLN-w-sulphobutyl-p-phenylene diamine 6 Made up with water to, 1000 ml.
• Developer 7 Without further additives.
• Developer 8 Pyrogallol, 0.025 g./l.
• Developer 9 Gallic acid, 0.03 g./l.
• Developer 10 Pyrrocatechol disnlphonic acid, 0.025 g/l.
• Developer 11 Potassium salt of 2,3-dihydroxy-naphthalene sulphonie acid-(6), 0.03 g./l.
• Developer 12 2,3,8-trihydroxy-naplithalene sulphonic acid-(6) 0.03 g./l.
• test series A the samples of developer were kept free from air for 10 days at 30 C. in bottles which were filled to the top.
• test series B the developers were kept in open vessels at room temperature for 10 days.
• test series C The samples of the test series C were kept at room temperature for 30 days in partly filled bottles to prevent excessive evaporation.
• EXAMPLE 4 The protective ell'ect of the o-dihydroxyaryl compounds can be demonstrated not only in developers which contain ethylene diaminotetracetic acid but also in developers which contain other water softeners :based on amino acetic acid, as will be clear from the following series of tests.
• composition of the developer is composition of the developer:
• Developer 14 The same as developer 13 with the addition of 0.1 g. of pyroeatechol disulphonic acid.
• Developer 15 4 g. of diethylene triaminopentacetic acid.
• Developer 16 The same as developer 15 with the addition of 0.1 g. of pyrocatechol disulphonic acid.
• Developer 17 4 g. of hydroxyethylethylene diaminotriacetic acid (41% in water).
• Developer 18 The same as developer 17 with the addition of 0.1 g. of pyrocatechol disulphonic acid.
• An aqueous color developer composition containing a p-phenylene diamine color developer and an aminopolycarboxylic acid water softener, said composition also having a water soluble aromatic polyhydroxyl compound having at least two hydroxy groups in ortho-position in relation to each other on the aromatic ring, said aromatic polyhydroxyl compound being an o-dihydroxy compound of the benzene or naphalene series so as to stabilize the developer mixture to atmospheric oxygen and in an amount of from 1 to 400 mg. per liter.
• a color developer composition according to claim 1 in which the o-dihydroxy compound is selected from the group consisting of pyrocatechol, pyrocatechol-3,5-disulphonic acid, pyrogallol, gallic acid and 2,3-dihydroxy naphthalene-6-sulphonic acid.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (5)

Cited By (26)

• 1970
  • 1970-04-01 DE DE19702015403 patent/DE2015403A1/de active Pending
• 1971
  • 1971-03-18 BE BE764442A patent/BE764442A/nl unknown
  • 1971-03-23 US US00127362A patent/US3746544A/en not_active Expired - Lifetime
  • 1971-04-01 FR FR7111551A patent/FR2089029A5/fr not_active Expired
  • 1971-04-19 GB GB2562471*A patent/GB1319564A/en not_active Expired

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