US4335199A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High contrast by imagewise iodide infection in a mixed silver halide system
Assignee: Agfa Gevaert NV
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Filing: 1980-02-19
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Granted: 1982-06-15
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Expires: 2000-02-19
Abstract
Abstract High contrast photographic images suitable for lithographic use are obtained with stable (nonlithographic) developers when iodide is released from a surface-sensitized iodobromide emulsion to induce development of the exposed areas in an internally sensitized core-shell emulsion. A bromoiodide or trihalide core is produced by balanced double jet precipitation, then the core is chemically sensitized and covered with a chlorobromide or chloride shell by balanced double jet precipitation or preferably by a cyclic pAg addition technique. The core-shell emulsion must have a sensitivity equal to or greater than the surface sensitized emulsion.
Inventors
- 👤 daniel J. Mickewich
- 👤 John R. Shock
- 👤 Daniel F. Juers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:30
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/035; G03C2001/03535; G03C2001/03564; Y; Y10; Y10S; Y10S430/00; Y10S430/15
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
71 words
A photographic element comprising a support, and a mixture of two non-fogged silver halide emulsions on said support: (1) an internally sensitized core-shell emulsion having an internal sensitivity equal to or greater than that of emulsion (2); (2) a surface-sensitized silver iodobromide or trihalide emulsion capable of releasing iodide ions upon being developed in a stable developer, which iodide ions serve to produce infectious development of exposed grains of emulsion (1).
Claim 2
Dependent Claim
71 words
A photographic element comprising a support, and a mixture of two non-fogged silver halide emulsions on said support: (1) an internally sensitized core-shell emulsion having an internal sensitivity equal to or greater than that of emulsion (2); (2) a surface-sensitized silver iodobromide or trihalide emulsion capable of releasing iodide ions upon being developed in a stable developer, which iodide ions serve to produce infectious development of exposed grains of emulsion (1).
Claim 3
Dependent Claim
13 words
The photographic element of claim 1 wherein emulsion (1) contains an iodobromide core.
Claim 4
Dependent Claim
13 words
The photographic element of claim 2 wherein emulsion (1) contains a chlorobromide shell.
Claim 5
Dependent Claim
17 words
The photographic element of claim 3 wherein the chloride content of the shell is greater than 50%.
Claim 6
Dependent Claim
24 words
The photographic element of claim 4 wherein the chlorobromide shell of the core-shell emulsion (1) is about 80 mole % Cl/20 mole % Br.
Claim 7
Dependent Claim
18 words
The photographic element of claim 1 wherein emulsions (1) and (2) are mixed in about a 1:1 ratio.
Claim 8
Dependent Claim
15 words
The photographic element of claim 1 wherein emulsion (2) contains rhodium to control the gradient.
Claim 9
Dependent Claim
24 words
The photographic element of claim 1 wherein emulsions (1) and (2) contain 4-hydroxy [3,4-d] pyrimidine in amount sufficient to act as a development accelerator.
Claim 10
Dependent Claim
139 words
A process wherein a photographic silver halide emulsion film coated upon a support is exposed, and the resulting latent image is translated into a visible silver image by action of a continuous tone developer, characterized in that the silver halide emulsion is composed of a mixture of two non-fogged silver halide emulsions (1) and (2), emulsion (1) being an internally sensitized core-shell emulsion having an internal sensitivity equal to or greater than that of emulsion (2); emulsion (2) being a surface-sensitized silver iodobromide or trihalide emulsion capable of releasing iodide ions upon being developed in a stable developer, and wherein during the development process iodide is released from the surface-sensitized iodobromide or trihalide emulsion to induce development of the exposed areas in the internally sensitized core-shell emulsion, whereby a high contrast photographic image suitable for lithographic use is obtained.
Claim 11
Dependent Claim
139 words
A process wherein a photographic silver halide emulsion film coated upon a support is exposed, and the resulting latent image is translated into a visible silver image by action of a continuous tone developer, characterized in that the silver halide emulsion is composed of a mixture of two non-fogged silver halide emulsions (1) and (2), emulsion (1) being an internally sensitized core-shell emulsion having an internal sensitivity equal to or greater than that of emulsion (2); emulsion (2) being a surface-sensitized silver iodobromide or trihalide emulsion capable of releasing iodide ions upon being developed in a stable developer, and wherein during the development process iodide is released from the surface-sensitized iodobromide or trihalide emulsion to induce development of the exposed areas in the internally sensitized core-shell emulsion, whereby a high contrast photographic image suitable for lithographic use is obtained.
Claim 12
Dependent Claim
25 words
The process of claim 9 wherein emulsions (1) and (2) are mixed together in approximately a 1:1 ratio prior to being coated on the support.
Claim 13
Dependent Claim
46 words
The process of claim 9 wherein internally sensitized core-shell emulsion (1) is produced by first forming a silver iodobromide or trihalide core by a balanced double jet precipitation, chemically sensitizing said core, and then covering the sensitized core with a silver chlorobromide or silver chloride shell.
Claim 14
Dependent Claim
27 words
The process of claim 11 wherein said silver chlorobromide or silver chloride shell is produced by balanced double jet precipitation or by a cyclic pAg addition technique.
Claim 15
Dependent Claim
23 words
The process of claim 11 wherein the sensitivity of said core-shell emulsion (1) is determined before the shell is precipitated on the core.
References Cited (Backward Citations)
US2592250A
Cited
US2996382A
Cited
US3178282A
Cited
US3206313A
Cited
US3598597A
Cited
US3695881A
Cited
US3761276A
Cited
US4035185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |