US4046570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hardening fixer for photographic silver halide material
Assignee: Agfa Gevaert NV
•
Filing: 1976-05-27
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Granted: 1977-09-06
•
Expires: 1996-05-27
Abstract
Abstract A hardening fiber composition for use in the processing of photographic silver halide elements is described which contains a 1-hydroxy-alkylidene diphosphonic acid the alkylidene group of which contains from 2 to 5 C-atoms.
Inventors
- 👤 Marcel Robert Fierens
- 👤 Renaat Frans Heylen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:46
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/38; G03C5/386; Y; Y10; Y10S; Y10S430/00; Y10S430/167
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
48 words
A hardening fixer composition for use in the processing of photographic silver halide elements, comprising a thiocyanate or thiosulphate silver halide solvent and an aluminum hardener, wherein the said fixer composition also contains a 1-hydroxy-alkylidene diphosphonic acid of the formula: ##STR2## n being 0, 1, 2, or 3.
Claim 2
Dependent Claim
48 words
A hardening fixer composition for use in the processing of photographic silver halide elements, comprising a thiocyanate or thiosulphate silver halide solvent and an aluminum hardener, wherein the said fixer composition also contains a 1-hydroxy-alkylidene diphosphonic acid of the formula: ##STR2## n being 0, 1, 2, or 3.
Claim 3
Dependent Claim
17 words
A hardening fixer according to claim 1, wherein the silver halide solvent is ammonium or sodium thiosulphate.
Claim 4
Dependent Claim
21 words
A hardening fixer according to claim 1, wherein the aluminium hardener is potassium or ammonium alum, aluminium chloride or aluminium sulphate.
Claim 5
Dependent Claim
17 words
A hardening fixer according to claim 1, wherein the hydroxy alkylidene diphosphonic acid is 1-hydroxy-ethylidene diphosphonic acid.
Claim 6
Dependent Claim
29 words
A hardening fixer according to claim 1, wherein the hydroxy alkylidene diphosphonic acid is added in an amount comprised between about 0.5 g to about 5 g per liter.
Claim 7
Dependent Claim
73 words
In a method of processing an imagewise exposed photographic silver halide element comprising the steps of developing by means of a developer comprising a silver halide developing agent and treating the developed element with a hardening fixer comprising an aluminum hardener and a thiocyanate or thiosulphate silver halide solvent, the improvement which comprises using in the fixer composition a 1-hydroxy-alkylidene diphosphonic acid of the formula: ##STR3## n being 0, 1, 2, or 3.
Claim 8
Dependent Claim
73 words
In a method of processing an imagewise exposed photographic silver halide element comprising the steps of developing by means of a developer comprising a silver halide developing agent and treating the developed element with a hardening fixer comprising an aluminum hardener and a thiocyanate or thiosulphate silver halide solvent, the improvement which comprises using in the fixer composition a 1-hydroxy-alkylidene diphosphonic acid of the formula: ##STR3## n being 0, 1, 2, or 3.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-05 | 1981-03-07 | 1981-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-05 | 1985-03-07 | 1985-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-05 | 1989-03-07 | 1989-09-06 | $7700.00 | Window Closed / Lapsed |