Radiation imagery chemistry: process – composition – or product th – Post imaging processing – Developing
Patent
1997-08-15
1998-06-23
Le, Hoa Van
Radiation imagery chemistry: process, composition, or product th
Post imaging processing
Developing
430436, 430439, 430440, 430478, 430480, 430481, 430482, 430483, 430489, G03C 529
Patent
active
057703515
DESCRIPTION:
BRIEF SUMMARY
Methods and techniques of photographic processing are well known, and are described for example, in the books Photographic Processing Chemistry by LFA Mason, published by the Focal Press in 1975, and Modern Photographic Processing by G. M. Haist, published by Wiley--Interscience in 1979. One well known method is to use a photographic processing machine comprising roller guides which feed the photographic material from one tank containing a photographic processing solution to the next. One of the troubles encountered when photographic material is processed in a machine comprising roller guides is the occurrence of physical development fog which exhibits itself as black silver marks on the processed print material present in a random fashion. It is not clear in some circumstances what causes this physical development of the silver but often in roller transport processing machines, the photographic material is fed from the tank containing the developing solution to the tank containing the fixer solution without any intermediate washing step. Also, to speed up processing, the temperature of the solutions in such machines is 30.degree. C. or above. When such machines are in use, a certain concentration of fixed-out silver builds up in the fixing solution. Processing conditions of this type tend to promote physical development fog. This physical development fog is thought to be caused by some developing solution still in the active state, being carried over into the fixing solution on the print material. This causes some fixed out silver which is in solution in the fixing bath to be developed into metallic silver which then is deposited on the print being processed. Various developing solution stabilizers have been tried to prevent this physical development fog but most are ineffective or have other deleterious effects. For instance, one or two which lessen physical development fog also cause bronzing of the print material which is highly undesirable.
Therefore it is the object of the present invention to provide a method of processing photographic print material wherein the occurrence of physical development fog is greatly reduced.
Therefore according to the present invention there is provided a method of processing silver halide photographic material in a processing machine using a developing solution which comprises either a hydroquinone type developing agent or a reductone type developing agent, together with an electron transfer agent as an auxiliary developing agent, and with at least one basic compound the anion of which is carbonate, sulphite or hydroxide, and a compound of formula I: ##STR2## where Ar is an aromatic ring or heterocyclic aromatic ring which is optionally substituted.
The method of the present invention is of particular use when the photographic material is print material which when it is processed is fed from the tank containing the developing solution to a tank containing the fixer solution without any intermediate washing step. Therefore according to this aspect of the present invention is a method of processing silver halide print material in a roller transport processing apparatus using a developing solution at a temperature of at least 30.degree. C. and wherein the print material is fed out of the developing solution straight into a fixing solution, the developing solution comprising either a hydroquinone type developing agent or a reductone developing agent, together with an electron transfer agent as an auxiliary developing agent, and with at least one basic compound the anion of which is carbonate, sulphite or hydroxide, there being present in the developing solution a compound of formula I: ##STR3## where Ar is an aromatic or heterocyclic aromatic ring which may be substituted. Suitable substituent groups comprise sulphonic acid groups and salts thereof, carboxylic acid groups and salts thereof halide for example fluoride or chloride, lower alkyl such as methyl or ethyl, lower alkoxy for example methoxy, or sulphonamide or carboxamide groups. Compounds of formula I are compounds
REFERENCES:
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patent: 4070188 (1978-01-01), Nakamura et al.
patent: 4777118 (1988-10-01), Kitchin et al.
patent: 4975354 (1990-12-01), Machonkin et al.
Long William Edward
Parker Michael John
Ilford Limited
Le Hoa Van
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