Patent US4694121A successfully refreshed from Google Patents.
Patent US3917485A successfully refreshed from Google Patents.
US3917485A
Expired / Lapsed
US
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Method of making photographic silver halide emulsions and products thereof
Assignee: Eastman Kodak Co
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Filing: 1974-09-03
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Granted: 1975-11-04
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Expires: 1994-09-03
Abstract
Abstract A method is disclosed of making an internally sensitive photographic silver halide emulsion. In this method further silver halide is laid down on the grains of a surface sensitive or surface fogged emulsion so that excesses of silver and halide ions are alternately produced. In one preferred form a desensitizer is added to the completed internally sensitive emulsion, which desensitizer has a cathodic polarographic halfwave potential less negative that -1.0 volt. In another preferred form a sensitizing dye can be added to the internally sensitive emulsion. The invention is also directed to the silver halide emulsions formed by these methods.
Inventors
- 👤 John Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:03
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48538; G03C1/015; G03C1/06; G03C1/08; G03C1/10; G03C1/12; G03C1/36; G03C1/035; G03C2001/03535; G03C2200/00; G03C2200/06
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
50 words
A METHOD OF MAKING AN INTERNALLY SENSITIVE PHOTOGRAHIC SILVER HALIDE EMULSION IN WHICH ADDITIONAL SILVER HALIDE IS PERCIPITATED ONTO SILVER HALIDE GRAINS OF A SURFACE SENSITIVE OR SURFACE FOGGED SILVER HALIDE EMULSION CHARACTERIZED IN THAT ALTERNATE EXCESS OF SILVER IONS AND HALIDE IONS ARE CAUSED TO BE PRESENT DURING PRECIPITATION.
Claim 2
Independent Claim
50 words
A METHOD OF MAKING AN INTERNALLY SENSITIVE PHOTOGRAHIC SILVER HALIDE EMULSION IN WHICH ADDITIONAL SILVER HALIDE IS PERCIPITATED ONTO SILVER HALIDE GRAINS OF A SURFACE SENSITIVE OR SURFACE FOGGED SILVER HALIDE EMULSION CHARACTERIZED IN THAT ALTERNATE EXCESS OF SILVER IONS AND HALIDE IONS ARE CAUSED TO BE PRESENT DURING PRECIPITATION.
Claim 3
Dependent Claim
78 words
A METHOD ACCORDING TO CLAIM 1 CHARACTERIZED IN THAT THE ALTERNATE EXCESS COMPRISE A PLAG ADJUSTMENT CYCLE IN WHICH SUFFICIENT SILVER SALT IS CAUSED TO BE PRESENT TO ADJUST THE PAG OF THE EMULSION SO THAT AN EXCESS OF SILVER IONS ARE PRESENT AS COMPARED TO HALIDE IONS AND SUFFICIENT ALKALI METAL HALIDE SALT IS THEN CAUSED TO BE PRESENT TO ADJUST THE PAG SO THAT AN EXCESDD OF HALIDE IONS ARE PRESENT AS COMPARED TO SILVER IONS.
Claim 4
Dependent Claim
22 words
A method according to claim 2 in which the silver salt is silver nitrate and the alkali metal salt is potassium halide.
Claim 5
Dependent Claim
21 words
A method according to claim 3 in which the potassium halide is at least one of potassium bromide and potassium iodide.
Claim 6
Dependent Claim
38 words
A method according to claim 2 in which the alternate excesses take place at a temperature of not more than 40*C and for times of from 15 to 30 seconds for each part of the pAg adjustment cycle.
Claim 7
Dependent Claim
34 words
A method according to claim 5 in which the pAg is at least 4 when an excess of silver ions are present and up to 10 when as excess of halide ions are present.
Claim 8
Dependent Claim
44 words
A method according to claim 5 in which the pAg is in the range of from 4 to 6.5 when an excess of silver ions are present and in the range of from 8 to 10 when an excess of halide ions are present.
Claim 9
Dependent Claim
15 words
A method according to claim 2 in which at least 3 pAg cycles are employed.
Claim 10
Dependent Claim
15 words
A method according to claim 5 in which at least 7 pAg cycles are employed.
Claim 11
Dependent Claim
22 words
A method according to claim 1 in which the surface sensitive or surface fogged silver halide emulsion is a silver bromoiodide emulsion.
Claim 12
Dependent Claim
28 words
A method according to claim 1 in which a spectral sensitizing dye or a desensitizer is caused to be present in the internally sensitive photographic silver halide emulsion.
Claim 13
Dependent Claim
33 words
A method according to claim 11 in which the sensitizing dye or desensitizer is added to the internally sensitive silver halide photographic emulsion after the precipitation of additional silver halide onto the grains.
Claim 14
Dependent Claim
35 words
A method according to claim 11 in which the sensitizing dye or desensitizer is added to the internally sensitive silver halide emulsion in a concentration that would at least partially desensitize the surface sensitive emulsion.
Claim 15
Dependent Claim
65 words
A method accOrding to claim 13 in which the sensitizing dye or desensitizer is added to the internally sensitive silver halide emulsion in a concentration that would produce a loss in blue speed sensitivity in a sulfur and gold surface sensitized silver bromoiodide emulsion (6 mole percent iodide) of similar grain size of at least 0.3 log E when developed in surface developer Kodak D-19.
Claim 16
Dependent Claim
26 words
A method according to claim 11 in which a desensitizer is caused to be present having a cathodic polarographic half-wave potential less negative than -1.0 volt.
Claim 17
Dependent Claim
19 words
A method according to claim 1 in which the surface sensitive emulsion has been chemically sensitized on its surface.
Claim 18
Dependent Claim
16 words
A method according to claim 16 in which the surface sensitive emulsion has been sulfur sensitized
Claim 19
Dependent Claim
29 words
A method according to claim 1 including the additional step of fogging the internally sensitive photographic silver halide emulsion to form an emulsion useful in forming direct positive images.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |