US3607263A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic reversal color process
Assignee: Eastman Kodak Co
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Filing: 1969-09-24
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Granted: 1971-09-21
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Expires: 1989-09-24
Abstract
Abstract A reversal color development process in photography is carried out at elevated temperatures using a first black-and-white silver halide developing solution at pH of about 9.1 to 9.6 and containing hydroquinone and an amount of a 3-pyrazolidone silver halide developing agent sufficient to inhibit fog on development of aged emulsion layers. This minimizes the density losses obtained with aged color films compared to fresh color films.
Inventors
- 👤 Julius Battaglini
- 👤 John H Goselin
- 👤 Walter P Horylev
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:15
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
138 words
In a photographic reversal color process wherein a photographic element comprising at least two superposed gelatin-silver halide emulsion layers sensitive to different regions of the spectrum is exposed to a colored image, silver images are developed in the emulsion layers in the regions of exposure using a first black-and-white silver halide developing solution at elevated temperature, and reversal colored images are developed in the remaining undeveloped regions of the emulsion layers at elevated temperature at least about 100* F., the improvement comprising using as said first developing solution an aqueous alkaline solution having a pH of about 9.1 to 9.6 and containing at least about 1.5 grams hydroquinone per liter and at least about 0.5 of 1-phenyl-3-pyrazolidone per liter or at least about 1.0 gram per liter of a 1-phenyl-3-pyrazolidone substituted in the 4-position of the pyrazolidone nucleus.
Claim 2
Dependent Claim
41 words
The process according to claim 1 wherein the emulsion layers of the photographic element contain color-forming coupler compounds reactive with primary aromatic amino silver halide developing agents to produce dye images of color complementary to light sensitivity of the respective layers.
Claim 3
Dependent Claim
32 words
The process according to claim 1 wherein the said first developer solution contains about 0.5 to 1.0 gram per liter of 1-phenyl-3-pyrazolidone and about 5 to 12 grams per liter of hydroquinone.
Claim 4
Dependent Claim
50 words
The process according to claim 1 wherein the emulsion layers of the photographic element are free of color-forming coupler compounds and reversal color development is carried out by means of color developing solutions containing couplers to produce dye images of colors complementary to the light sensitivity of the emulsion layers.
Claim 5
Dependent Claim
35 words
The process according to claim 3 wherein the said first developer solution contains about 1.0 to 2.5 grams per liter of 1-phenyl-4-methyl-3-pyrazolidone, 1-phenyl-4-hydroxymethyl-3-pyrazolidone or 1-phenyl-4,4-bis(hydroxymethyl)-3pyrazolidone and about 1.5 to 24.0 grams per liter of hydroquinone.
Claim 6
Dependent Claim
31 words
The process according to claim 3 wherein, prior to the first development step the emulsion layers are prehardened using an acidic aldehydic gelatin hardening solution followed by an aldehyde neutralizing solution.
References Cited (Backward Citations)
US3221023A
Cited
US3241967A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |