GB2303462A - Photographic developers - Google Patents
Photographic developers Download PDFInfo
- Publication number
- GB2303462A GB2303462A GB9514295A GB9514295A GB2303462A GB 2303462 A GB2303462 A GB 2303462A GB 9514295 A GB9514295 A GB 9514295A GB 9514295 A GB9514295 A GB 9514295A GB 2303462 A GB2303462 A GB 2303462A
- Authority
- GB
- United Kingdom
- Prior art keywords
- developing solution
- formaldehyde
- solution according
- photographic
- photographic developing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 84
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims description 27
- 150000001875 compounds Chemical class 0.000 claims description 21
- 229960005070 ascorbic acid Drugs 0.000 claims description 12
- -1 alkali metal salts Chemical class 0.000 claims description 11
- 235000010323 ascorbic acid Nutrition 0.000 claims description 11
- 239000011668 ascorbic acid Substances 0.000 claims description 11
- 239000003795 chemical substances by application Substances 0.000 claims description 11
- 229910052783 alkali metal Inorganic materials 0.000 claims description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims description 8
- 125000000217 alkyl group Chemical group 0.000 claims description 7
- CIWBSHSKHKDKBQ-DUZGATOHSA-N D-isoascorbic acid Chemical compound OC[C@@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-DUZGATOHSA-N 0.000 claims description 6
- 150000001340 alkali metals Chemical class 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- XUIVKWAWICCWIQ-UHFFFAOYSA-M sodium;formaldehyde;hydrogen sulfite Chemical group [Na+].O=C.OS([O-])=O XUIVKWAWICCWIQ-UHFFFAOYSA-M 0.000 claims description 5
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 claims description 5
- 150000000996 L-ascorbic acids Chemical class 0.000 claims description 4
- 239000012992 electron transfer agent Substances 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims description 4
- ZVNPWFOVUDMGRP-UHFFFAOYSA-N 4-methylaminophenol sulfate Chemical group OS(O)(=O)=O.CNC1=CC=C(O)C=C1.CNC1=CC=C(O)C=C1 ZVNPWFOVUDMGRP-UHFFFAOYSA-N 0.000 claims description 3
- QIGBRXMKCJKVMJ-UHFFFAOYSA-N Hydroquinone Chemical compound OC1=CC=C(O)C=C1 QIGBRXMKCJKVMJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000002211 L-ascorbic acid Substances 0.000 claims description 3
- 235000000069 L-ascorbic acid Nutrition 0.000 claims description 3
- 239000000837 restrainer Substances 0.000 claims description 3
- 239000003352 sequestering agent Substances 0.000 claims description 3
- 125000003118 aryl group Chemical group 0.000 claims description 2
- 125000002768 hydroxyalkyl group Chemical group 0.000 claims description 2
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 2
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 4
- 238000002835 absorbance Methods 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- JNGZXGGOCLZBFB-IVCQMTBJSA-N compound E Chemical compound N([C@@H](C)C(=O)N[C@@H]1C(N(C)C2=CC=CC=C2C(C=2C=CC=CC=2)=N1)=O)C(=O)CC1=CC(F)=CC(F)=C1 JNGZXGGOCLZBFB-IVCQMTBJSA-N 0.000 description 3
- 230000003226 decolorizating effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 125000000325 methylidene group Chemical group [H]C([H])=* 0.000 description 3
- PPASLZSBLFJQEF-RXSVEWSESA-M sodium-L-ascorbate Chemical compound [Na+].OC[C@H](O)[C@H]1OC(=O)C(O)=C1[O-] PPASLZSBLFJQEF-RXSVEWSESA-M 0.000 description 3
- WYMDDFRYORANCC-UHFFFAOYSA-N 2-[[3-[bis(carboxymethyl)amino]-2-hydroxypropyl]-(carboxymethyl)amino]acetic acid Chemical compound OC(=O)CN(CC(O)=O)CC(O)CN(CC(O)=O)CC(O)=O WYMDDFRYORANCC-UHFFFAOYSA-N 0.000 description 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- QPCDCPDFJACHGM-UHFFFAOYSA-N N,N-bis{2-[bis(carboxymethyl)amino]ethyl}glycine Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(=O)O)CCN(CC(O)=O)CC(O)=O QPCDCPDFJACHGM-UHFFFAOYSA-N 0.000 description 2
- 239000004285 Potassium sulphite Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 229940072107 ascorbate Drugs 0.000 description 2
- 229960001484 edetic acid Drugs 0.000 description 2
- QUBQYFYWUJJAAK-UHFFFAOYSA-N oxymethurea Chemical compound OCNC(=O)NCO QUBQYFYWUJJAAK-UHFFFAOYSA-N 0.000 description 2
- 229950005308 oxymethurea Drugs 0.000 description 2
- 229960003330 pentetic acid Drugs 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- BHZRJJOHZFYXTO-UHFFFAOYSA-L potassium sulfite Chemical compound [K+].[K+].[O-]S([O-])=O BHZRJJOHZFYXTO-UHFFFAOYSA-L 0.000 description 2
- 235000019252 potassium sulphite Nutrition 0.000 description 2
- LVTJOONKWUXEFR-FZRMHRINSA-N protoneodioscin Natural products O(C[C@@H](CC[C@]1(O)[C@H](C)[C@@H]2[C@]3(C)[C@H]([C@H]4[C@@H]([C@]5(C)C(=CC4)C[C@@H](O[C@@H]4[C@H](O[C@H]6[C@@H](O)[C@@H](O)[C@@H](O)[C@H](C)O6)[C@@H](O)[C@H](O[C@H]6[C@@H](O)[C@@H](O)[C@@H](O)[C@H](C)O6)[C@H](CO)O4)CC5)CC3)C[C@@H]2O1)C)[C@H]1[C@H](O)[C@H](O)[C@H](O)[C@@H](CO)O1 LVTJOONKWUXEFR-FZRMHRINSA-N 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000011755 sodium-L-ascorbate Substances 0.000 description 2
- 235000019187 sodium-L-ascorbate Nutrition 0.000 description 2
- 238000004659 sterilization and disinfection Methods 0.000 description 2
- KGRVJHAUYBGFFP-UHFFFAOYSA-N 2,2'-Methylenebis(4-methyl-6-tert-butylphenol) Chemical compound CC(C)(C)C1=CC(C)=CC(CC=2C(=C(C=C(C)C=2)C(C)(C)C)O)=C1O KGRVJHAUYBGFFP-UHFFFAOYSA-N 0.000 description 1
- WDGCBNTXZHJTHJ-UHFFFAOYSA-N 2h-1,3-oxazol-2-id-4-one Chemical class O=C1CO[C-]=N1 WDGCBNTXZHJTHJ-UHFFFAOYSA-N 0.000 description 1
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001447 alkali salts Chemical class 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- QRUDEWIWKLJBPS-UHFFFAOYSA-N benzotriazole Chemical compound C1=CC=C2N[N][N]C2=C1 QRUDEWIWKLJBPS-UHFFFAOYSA-N 0.000 description 1
- 239000012964 benzotriazole Substances 0.000 description 1
- 125000003354 benzotriazolyl group Chemical class N1N=NC2=C1C=CC=C2* 0.000 description 1
- 230000003115 biocidal effect Effects 0.000 description 1
- 239000003139 biocide Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 1
- DUYCTCQXNHFCSJ-UHFFFAOYSA-N dtpmp Chemical compound OP(=O)(O)CN(CP(O)(O)=O)CCN(CP(O)(=O)O)CCN(CP(O)(O)=O)CP(O)(O)=O DUYCTCQXNHFCSJ-UHFFFAOYSA-N 0.000 description 1
- NFDRPXJGHKJRLJ-UHFFFAOYSA-N edtmp Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CCN(CP(O)(O)=O)CP(O)(O)=O NFDRPXJGHKJRLJ-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- LQPLDXQVILYOOL-UHFFFAOYSA-I pentasodium;2-[bis[2-[bis(carboxylatomethyl)amino]ethyl]amino]acetate Chemical compound [Na+].[Na+].[Na+].[Na+].[Na+].[O-]C(=O)CN(CC([O-])=O)CCN(CC(=O)[O-])CCN(CC([O-])=O)CC([O-])=O LQPLDXQVILYOOL-UHFFFAOYSA-I 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 150000003009 phosphonic acids Chemical class 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- NDGRWYRVNANFNB-UHFFFAOYSA-N pyrazolidin-3-one Chemical class O=C1CCNN1 NDGRWYRVNANFNB-UHFFFAOYSA-N 0.000 description 1
- PPASLZSBLFJQEF-RKJRWTFHSA-M sodium ascorbate Substances [Na+].OC[C@@H](O)[C@H]1OC(=O)C(O)=C1[O-] PPASLZSBLFJQEF-RKJRWTFHSA-M 0.000 description 1
- 235000010378 sodium ascorbate Nutrition 0.000 description 1
- 229960005055 sodium ascorbate Drugs 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- 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
- G03C5/30—Developers
-
- 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
-
- 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
- G03C5/30—Developers
- G03C2005/3007—Ascorbic acid
-
- 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
- G03C2200/00—Details
- G03C2200/44—Details pH value
-
- 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
- G03C5/30—Developers
- G03C5/3028—Heterocyclic compounds
- G03C5/3035—Heterocyclic compounds containing a diazole ring
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
Description
This invention relates to ascorbic acid based developing solutions for use with silver halide photographic materials.
It is well known that ascorbic acid and related compounds are useful as the main developing agents in silver halide photography, as described, for example, in the book 'Photographic Processing
Chemistry' by L.F.A. Mason, published by the Focal Press in 1975. Of late there has been increasing interest in the use of ascorbic acid based developing solutions on environmental grounds, as shown for example in US Patent 5,098,819.
There are, however, disadvantages in the use of ascorbic acid in photographic processing solutions, for example, one defect is that solutions, especially ready-to-use solutions, ie not concentrated solutions, discolour very rapidly when exposed to atmospheric conditions at the basic pH necessary for photographic development.
It is the object of the present invention to provide an additive which stabilises such solutions against the development of such discolouration.
Therefore, according to the present invention there is provided a photographic developing solution for black and white photographic material which comprises an ascorbic acid type compound of the general formula I:
wherein R is a hydroxylated alkyl group having 1 to 4 carbon atoms or alkali metal salts of such compounds, and formaldehyde or a source of formaldehyde as a stain preventing agent.
By source of formaldehyde is meant a compound which may or may not be prepared from formaldehyde, but which renders the elements of formaldehyde potentially available by breakdown in the processing solution. Suitable compounds include sodium formaldehyde bisulphite, 2.2'methylene bis(oxy)bis ethanol, N-methylol compounds such as dimethylol urea, and so-called formaldehyde donor compounds such as oxazolidones. Such compounds are well known, and are used as biocides, as described, for example, in the book Disinfection,
Preservation, and Sterilisation, edited by A.D. Russell, W.B. Hugo, and G.A.J. Ayliffe, published by Blackwell in 1992.
However, it is not thought that the biocidal properties of these formaldehyde releasing compounds are relevant to the present invention. Hereinafter the term source of formaldehyde will be used to cover all the above compounds, including formaldehyde itself. A particularly preferred source of formaldehyde for the present invention is sodium formaldehyde bisulphite.
Preferred examples of ascorbic acid type compounds included in general formula I are L-ascorbic acid, and D-iso ascorbic acid.
These compounds are substantially present in the anionic form at the pH of photographic developing solutions.
Alternatively the invention is also of use in photographic developing solutions which comprise hydroquinone together with an ascorbic acid type compound of formula I. Such developing solutions are described, for example in PCT WO 93/12463.
The developing solutions of the invention advantageously include a superadditive developing agent which acts as an electron transfer agent.
vEe prefe;rad electron transfer agents which act as super-additive developing agents are metol and pyrazolidinone compounds of the general formula II
wherein R1 and R2 are each hydrogen, alkyl groups having 1 to 4 carbon atoms or hydroxy alkyl groups having 1 to 4 carbon atoms1 R5 is an aromatic ring which is optionally substituted and R3 and R4 are each hydrogen, alkyl groups having 1 to 4 carbon atoms or phenyl.
The preferred superadditive developer of formula II is l-phenyl-4-methyl-4-hydroxymethyl-pyrazolidin-3-one which is hereinafter referred to as developing agent A. Most preferably this is present in the working strength developing solution at a concentration of 0.2 to 0.8g/litre.
Other classes of compound which may be present in the developing solution include restrainers such as potassium bromide, antifoggants such as benzotriazole compounds, and sequestering agents such as ethylenediamine tetra-acetic acid, (EDTA) diaminopropanol tetraacetic acid (DAPTA) and diethylenetriamine pentaacetic acid (DTPA), or phosphonic acids such as l-hydroxyethylidene l,1-diphosphonic acid, diethylenetriamine penta (methylene phosphonic acid), ethylenediamine tetra (methylene phosphonic acid) and nitrolotris (methylene phosphonic acid) and alkali metal salts thereof.
Preferably there is present in the working strength black and white developing solution as just set forth an alkali metal sulphite. Most preferably potassium sulphite or sodium sulphite are used. A suitable concentration of alkali metal sulphite is from 5 to 20g/litre.
The pH of the developing solution is at least 8. Preferably it is between 9 and 11. Such a pH may be achieved by the inclusion of an alkali metal sulphite, as set forth above. Alternatively, and preferably when the pH is 10 or above, sodium or potassium carbonate is used in addition to the suiphite as set forth above. Otherwise a suitable pH may be achieved by the use of caustic alkali, or borate or other basic salts.
In one method of the invention the source of formaldehyde is present in the ascorbic acid based working strength developing solution. In another method of the invention the source of formaldehyde is present in the black and white photographic material which is being processed, but this is not preferred. A combination of these two methods may also be used.
A suitable concentration of the source of formaldehyde is up to about 50g/litre. Depending on the molecular weight, a preferred quantity is between about 10 and 20 g/litre.
A suitable concentration of the ascorbic acid compound I is between about 5 and 15 g/litre.
The following specific sources of formaldehyde are of use in the invention, as described in the examples which follow. However, the invention is not limited to these compounds.
Compound B Sodium formaldehyde bisulphite
Compound C 2,2' methylene (bis) oxy bis ethanol
HO CH2 CH2 0 CH2 0 CH2 CH2 OH
Compound D Dimethylol urea
HO CH2 NH CO NH CH2 OH
Compound E l-Aza-3, 7-dioxo-5-ethyl bicyclo (3,3,0) octane
Example 1 The following ascorbate based developing solution was prepared:
Potassium sulphite (65% w/v) 15cm3 DTPA Na5 (37% w/v) 6.8cm3 Developing Agent A 0.5g
Sodium-L-Ascorbate 8g
Potassium bromide lg
Benzotriazole 0.02g
Potassium Carbonate 20g
Water - > 1L
pH - 10.30
To litre portions of this solution was added: : - Nothing 3 - 1.6 cm 38% w/v formaldehyde - 3.2 cm - 6.4 cm 3 - 9. 6 cm These solutions were left standing for 14 days and the colour of the solutions was measured initially and then at periodic intervals. The change in light absorbance at 400 nm was determined.
An absorbance of 0.05 is a light yellow colour but an absorbance of 0.2 is a strong yellow colour.
These results are shown in figure 1.
From these results it can be seen that the addition of formaldehyde has a strong decolouring effect. The addition of 1. 6cm3/L of 38% w/v formaldehyde has a useful decolourising effect, but the most beneficial effect occurs at a concentration of 3.2 cm /L and higher.
3.2 cm3/L 38% w/v formaldehyde corresponds to a 1:1 sodium ascorbate to formaldehyde molar ratio.
Example 2
The ascorbate based developing solution described in Example 1 was prepared.
To 1L portions of this solution was added: - Nothing - 3.2 cm3/L 38% w/v formaldehyde - 5.4 gl 1 Compound B - 4.7 cm3/L Compound C - 4.8 cm /L Compound D - 57 cm3/L of a 108 solution of Compound E
Each of these compounds were added at a 1:1 molar ratio with sodium-L-ascorbate. The results are shown in Figure 2.
From the results it can be seen that Compounds C and D offer a decolourising effect at least as good as formaldehyde. Compound B is not as effective, but is still significantly better than a developing solution with no decolourising additive present. Compound E is itself yellow coloured, but build up of additional yellow colour was inhibited.
Claims (8)
1. A photographic developing solution for black and white
photographic material which comprises an ascorbic acid type
compound of the general formula I:
wherein R is a hydroxylated alkyl group having 1 to 4 carbon
atoms or alkali metal salts of such compounds, and formaldehyde
or a source of formaldehyde as a stain preventing agent.
2. A photographic developing solution according to claim 1 wherein~
the ascorbic acid is L-ascorbic acid or D-iso ascorbic acid.
3. A photographic developing solution according to claim 1 wherein
the source of formaldehyde is sodium formaldehyde bisulphite.
4. A photographic developing solution according to claim 1 which
also comprises a superadditive developing agent.
5. A photographic developing solution according to claim 4 wherein
the superadditive developing agent is metol or a pyrazolidinone
compound.
6. A photographic developing solution according to claim 1 which
also comprises a restrainer, a sequestering agent and or alkali
metal sulphite.
7. A photographic developing solution according to claim 1 wherein
the pH of the developing solution is at least 8.
8. A photographic developing solution according to claim 1 wherein the amount
of formaldehyde present is between 10 and 20g'litre.
8. A photographic developing solution according to claim 7 wherein
the pH of the developing solution is between 9 and 11.
9. A photographic developing solution according to claim 1 wherein
the amount of formaldehyde present is between 10 and 20g/litre.
Amendments to the claims have been filed as follows
Claims:1. A photographic developing solution for black and white photographic material
which comprises an ascorbic acid type compound of the general formula I:
wherein R is a hydroxylated alkyl group having 1 to 4 carbon atoms or alkali metal salts of such compounds, together with an electron transfer agent which is metol or a pyrazolidinone compound of the general formula II::-
wherein R, and R2 are each hydrogen, alkyl groups having 1 to 4 carbon atoms or hydroxy alkyl groups having 1 to 4 carbon atoms, Rs is an aromatic ring which is optionally substituted and R3 and R4 are each hydrogen, alkyl groups having 1 to 4 carbon atoms or phenyl and formaldehyde or a source of
formaldehyde as a stain preventing agent, there being no dihydroxy benzene
developing agent present in the solution.
2. A photographic developing solution according to claim 1 wherein the ascorbic
acid is L-ascorbic acid or D-iso ascorbic acid.
3. A photographic developing solution according to claim 1 wherein the source of
formaldehyde is sodium formaldehyde bisulphite.
4. A photographic developing solution wherein the electron transfer agent is
1 -phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidium-3 -one.
5. A photographic developing solution according to claim 1 which also comprises
a restrainer, a sequestering agent and or alkali metal sulphite.
6. A photographic developing solution according to claim 1 wherein the pH of the
developing solution is at least 8.
7. A photographic developing solution according to claim 6 wherein the pH of the
developing solution is between 9 and 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9514295A GB2303462A (en) | 1995-07-13 | 1995-07-13 | Photographic developers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9514295A GB2303462A (en) | 1995-07-13 | 1995-07-13 | Photographic developers |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9514295D0 GB9514295D0 (en) | 1995-09-13 |
| GB2303462A true GB2303462A (en) | 1997-02-19 |
Family
ID=10777569
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9514295A Withdrawn GB2303462A (en) | 1995-07-13 | 1995-07-13 | Photographic developers |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2303462A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB928390A (en) * | 1958-07-02 | 1963-06-12 | Kodak Ltd | Improvements in photographic half-tone reproduction |
| GB1266533A (en) * | 1969-02-05 | 1972-03-08 | ||
| GB1326495A (en) * | 1970-03-20 | 1973-08-15 | Fuji Photo Film Co Ltd | Photographic developer concentrates |
| GB1365236A (en) * | 1971-07-20 | 1974-08-29 | Fuji Photo Film Co Ltd | Developing silver halide photographic material |
| GB1395958A (en) * | 1971-08-21 | 1975-05-29 | Fuji Photo Film Co Ltd | Process and composition for developing silver halide photo- lithographic material |
| EP0052317A1 (en) * | 1980-11-16 | 1982-05-26 | Hanetz International, Inc. | A developer for the development of lith or line films |
-
1995
- 1995-07-13 GB GB9514295A patent/GB2303462A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB928390A (en) * | 1958-07-02 | 1963-06-12 | Kodak Ltd | Improvements in photographic half-tone reproduction |
| GB1266533A (en) * | 1969-02-05 | 1972-03-08 | ||
| GB1326495A (en) * | 1970-03-20 | 1973-08-15 | Fuji Photo Film Co Ltd | Photographic developer concentrates |
| GB1365236A (en) * | 1971-07-20 | 1974-08-29 | Fuji Photo Film Co Ltd | Developing silver halide photographic material |
| GB1395958A (en) * | 1971-08-21 | 1975-05-29 | Fuji Photo Film Co Ltd | Process and composition for developing silver halide photo- lithographic material |
| EP0052317A1 (en) * | 1980-11-16 | 1982-05-26 | Hanetz International, Inc. | A developer for the development of lith or line films |
Non-Patent Citations (1)
| Title |
|---|
| Research Disclosure, March 1995,No 37152,Ascorbic acid developer,pages185-7,219,222-3 * |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9514295D0 (en) | 1995-09-13 |
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| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) | ||
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) |