US4444874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic elements containing direct-positive emulsions and processes for their use
Assignee: Eastman Kodak Co
•
Filing: 1982-09-15
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Granted: 1984-04-24
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Expires: 2002-09-15
Abstract
Abstract Photographic elements particularly adapted for forming direct-positive images are disclosed in which a radiation-sensitive core-shell emulsion layer and a silver halide emulsion layer incapable of forming a surface latent image within the direct-positive exposure latitude of the first emulsion layer and containing a grain population capable of internally trapping photolytically generated electrons are both present. The photographic elements are capable of exhibiting increased covering power, greater maximum density, and increased speed.
Inventors
- 👤 Robert A. Silverman
- 👤 Harry A. Hoyen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:33
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48538; G03C1/48569; Y; Y10; Y10S; Y10S430/00; Y10S430/141
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
114 words
A photographic element particularly adapted to forming a direct-positive image comprised of a support and, located on said support, a first, radiation-sensitive emulsion layer containing core-shell silver halide grain population having a coefficient of variation of less than 20%, and a second silver halide emulsion layer substantially incapable of forming a surface latent image within the direct-positive exposure latitude of the first emulsion layer and containing a second grain population capable of internally trapping photolytically generated electrons, said second grain population having an average diameter less than 70% that of said first grain population, and said first and second silver halide grain populations being present in a weight ratio of from 5:1 to 1:5.
Claim 2
Dependent Claim
114 words
A photographic element particularly adapted to forming a direct-positive image comprised of a support and, located on said support, a first, radiation-sensitive emulsion layer containing core-shell silver halide grain population having a coefficient of variation of less than 20%, and a second silver halide emulsion layer substantially incapable of forming a surface latent image within the direct-positive exposure latitude of the first emulsion layer and containing a second grain population capable of internally trapping photolytically generated electrons, said second grain population having an average diameter less than 70% that of said first grain population, and said first and second silver halide grain populations being present in a weight ratio of from 5:1 to 1:5.
Claim 3
Dependent Claim
14 words
A photographic element according to claim 1 additionally including a nucleating agent incorporated therein.
Claim 4
Dependent Claim
24 words
A photographic element according to claim 1 wherein said first, core-shell grain population is sensitized with at least one of sulfur, selenium, and gold.
Claim 5
Dependent Claim
21 words
A photographic element according to claim 1 wherein said second silver halide grain population is comprised of core-shell silver halide grains.
Claim 6
Dependent Claim
23 words
A photographic element according to claim 4 wherein said core-shell grains of said second grain population are substantially free of surface chemical sensitization.
Claim 7
Dependent Claim
22 words
A photographic element according to claim 1 wherein at least said core-shell grains of said first grain population are comprised of bromide.
Claim 8
Dependent Claim
19 words
A photographic element according to claim 6 wherein said bromide containing silver halide grains are additionally comprised of iodide.
Claim 9
Dependent Claim
25 words
A photographic element according to claim 1 wherein said second grain population has an average diameter less than 50% that of said first grain population.
Claim 10
Dependent Claim
25 words
A photographic element according to claim 8 wherein said second grain population has an average diameter less than 40% total of said first grain population.
Claim 11
Dependent Claim
27 words
A photographic element according to claim 1 wherein said first and second silver halide grain populations are present in a weight ratio of from 2:1 to 1:3.
Claim 12
Dependent Claim
18 words
A photographic element according to claim 1 wherein said first, core-shell grain population is comprised of tabular grains.
Claim 13
Dependent Claim
55 words
A photographic element according to claim 11 wherein said grains of said first grain population having a thickness of less than 0.5 micron and a diameter greater than 0.6 micron have an average aspect ratio greater than 8:1 and account for greater than 50% of the total projected surface area of said first grain population.
Claim 14
Dependent Claim
20 words
A photographic element according to claim 1 wherein said second emulsion layer nearer said support than said first emulsion layer.
Claim 15
Dependent Claim
16 words
A photographic element according to claim 13 wherein said first emulsion layer contains a nucleating agent.
Claim 16
Dependent Claim
31 words
A photographic element according to claim 1 wherein said second emulsion layer is positioned to be contacted during processing with a nucleating agent no later than being contacted with an antifoggant.
Claim 17
Dependent Claim
25 words
A photographic element according to claim 15 wherein said second emulsion layer contains a nucleating agent adsorbed to the surfaces of said second grain population.
Claim 18
Dependent Claim
31 words
A photographic element according to claim 1 in which said second core-shell grain population increases the minimum density of said emulsion layers to no more than 20% of their maximum density.
Claim 19
Dependent Claim
38 words
A photographic element according to claim 1 in which said first core-shell grain population contains a divalent or trivalent metal ion chosen from the group consisting of cadmium, lead, and erbium in an amount sufficient to reduce rereversal.
Claim 20
Dependent Claim
37 words
A photographic element according to claim 1 in which said first core-shell grain population exhibits a coefficient of variation of less than 10% and said photographic element is capable of producing a contrast of greater than 10.
Claim 21
Dependent Claim
31 words
A photographic element according to claim 1 in which said second core-shell grain population increases the minimum density of the photographic element to no more than 5% of its maximum density.
Claim 22
Dependent Claim
21 words
A photographic element according to claim 1 in which said second grain population is comprised of converted halide silver halide grains.
Claim 23
Dependent Claim
21 words
A photographic element according to claim 1 in which said second grain population is comprised of internally fogged silver halide grains.
Claim 24
Dependent Claim
39 words
Processing in a surface developer an imagewise exposed photographic element according to any one of claims 1 through 22 (a) in the presence of a nucleating agent, or (b) with light flashing of the exposed photographic element during processing.
References Cited (Backward Citations)
US2456953A
Cited
US2592250A
Cited
US3206313A
Cited
US3846135A
Cited
US3615573A
Cited
US3600180A
Cited
US3761276A
Cited
US3850637A
Cited
US3854953A
Cited
US3846128A
Cited
US3923513A
Cited
US3942986A
Cited
US4035185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |