US4174968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic reversal process without second exposure
Assignee: Agfa Gevaert AG
•
Filing: 1977-12-29
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Granted: 1979-11-20
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Expires: 1997-12-29
Abstract
Abstract A photographic reversal process is provided in which the photographic material is treated with a potential fogging agent in the preliminary bath preceding the color development bath in such a manner as to obviate the disadvantages of known chemical fogging agents.
Inventors
- 👤 Karl Frank
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:27
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
157 words
In a photographic reversal process for the production of positive photographic images comprising the steps of first imagewise exposure of a light sensitive material comprising at least one silver halide emulsion layer and then black and white development of said exposed material in a first development, subsequent to said black and white development treatment of the exposed and developed material in a preliminary bath with an agent selected from the group consisting of metal ions of metals of the transition elements, hydrazine salts or salts of hydrazine derivatives, hydroxylamine salts or salts of hydroxylamine derivatives, iminoaminomethane sulphinic acid compounds and thiourea dioxide, and then further treating the material in an alkaline bath, and subsequently color development of the exposed and developed and treated material by reaction of the color couplers with oxidized color developer, so as to provide the exposed and developed and treated material with chemical fogging after black and white development and before color development.
Claim 2
Dependent Claim
157 words
In a photographic reversal process for the production of positive photographic images comprising the steps of first imagewise exposure of a light sensitive material comprising at least one silver halide emulsion layer and then black and white development of said exposed material in a first development, subsequent to said black and white development treatment of the exposed and developed material in a preliminary bath with an agent selected from the group consisting of metal ions of metals of the transition elements, hydrazine salts or salts of hydrazine derivatives, hydroxylamine salts or salts of hydroxylamine derivatives, iminoaminomethane sulphinic acid compounds and thiourea dioxide, and then further treating the material in an alkaline bath, and subsequently color development of the exposed and developed and treated material by reaction of the color couplers with oxidized color developer, so as to provide the exposed and developed and treated material with chemical fogging after black and white development and before color development.
Claim 3
Dependent Claim
22 words
Process according to claim 1, characterised in that the potential fogging agents used are compounds of titanium, manganese, iron, cobalt or cerium.
Claim 4
Dependent Claim
16 words
Process according to claim 1, characterised in that the potential fogging agents used are iron compounds.
Claim 5
Dependent Claim
16 words
Process according to claim 1, characterised in that the potential fogging agents used are titanium compounds.
Claim 6
Dependent Claim
20 words
Process according to claim 1, characterised in that the metal ions are present as complex compounds before and after fogging.
Claim 7
Dependent Claim
18 words
Process according to claim 5, characterised in that the metal ions are present as complex compounds after fogging.
Claim 8
Dependent Claim
25 words
Process according to claim 5, characterised in that carboxylic acids, phosphonic acids or phosphono carboxylic acids are used as complexing agents for the metal ions.
Claim 9
Dependent Claim
31 words
Process according to claim 7, characterised in that the complexing agents for the metal ions are hydroxycarboxylic acids, polycarboxylic acids, hydroxypolycarboxylic acids, polyhydroxypolycarboxylic acids, aminoalkylcarboxylic acids, hydroxyalkylidenephosphonic acids aminoalkyl phosphonic acids.
Claim 10
Dependent Claim
28 words
Process according to claim 7, characterised in that the complexing agents used are oxalic acid, citric acid, ethylene diaminotetracetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, tartaric acid or nitrilotrimethylene triphosphonic acid.
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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) | 1982-11-19 | 1983-05-21 | 1983-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-19 | 1987-05-21 | 1987-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-19 | 1991-05-21 | 1991-11-20 | $7700.00 | Window Closed / Lapsed |