US3900323A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic element comprising an opaque backcoat
Assignee: Polaroid Corp
•
Filing: 1973-10-23
•
Granted: 1975-08-19
•
Expires: 1993-10-23
Abstract
Abstract A backing or antihalation layer for a photosensitive element containing carbon black additionally contains a salt of a heavy metal. The heavy metal inhibits fog formation in the silver halide emulsion of the photosensitive element.
Inventors
- 👤 William T Macleish
- 👤 Terry W Milligan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:11
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/76; G03C1/825; G03C1/8255
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
36 words
A PHOTOGRAPHIC ELEMENT WHICH INCLUDES AT LEAST ONE SILVER HALIDE EMULSION LAYER AND WHICH ALSO INCLUDES A LAYER CONTAINING CARBON BLACK AND A WATER-SOLUBLE SALT OF A HEAVY METAL CAPABLE OF FORMING A RELATIVELY INSOLUBLE SULFIDE.
Claim 2
Dependent Claim
36 words
A PHOTOGRAPHIC ELEMENT WHICH INCLUDES AT LEAST ONE SILVER HALIDE EMULSION LAYER AND WHICH ALSO INCLUDES A LAYER CONTAINING CARBON BLACK AND A WATER-SOLUBLE SALT OF A HEAVY METAL CAPABLE OF FORMING A RELATIVELY INSOLUBLE SULFIDE.
Claim 3
Dependent Claim
27 words
A product as defined in claim 1 wherein said metal is selected from the group consisting of silver, copper, platinum, palladium, zinc, cadmium, lead, iron and bismuth.
Claim 4
Dependent Claim
30 words
A product as defined in claim 2 which includes a support carrying said carbon black layer on a first side and said silver halide emulsion layer on said second side.
Claim 5
Dependent Claim
15 words
A product as defined in claim 1 wherein said heavy metal salt is silver nitrate.
Claim 6
Dependent Claim
31 words
A product as defined in claim 1 wherein said heavy metal salt is present at a level of at least 100 ppm based on the weight of said carbon black layer.
Claim 7
Dependent Claim
16 words
A product as defined in claim 1 wherein said carbon black layer includes a polymeric binder.
Claim 8
Dependent Claim
14 words
A product as defined in claim 6 wherein said polymeric binder includes polyvinyl alcohol.
References Cited (Backward Citations)
US1434453A
Cited
US2386627A
Cited
US2791504A
Cited
US3060025A
Cited
US3269252A
Cited
US3511660A
Cited
US3758376A
Cited
US3832218A
Cited
US3793029A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |