US1628445A - Georges emmanuel zelger - Google Patents
Georges emmanuel zelger Download PDFInfo
- Publication number
- US1628445A US1628445A US1628445DA US1628445A US 1628445 A US1628445 A US 1628445A US 1628445D A US1628445D A US 1628445DA US 1628445 A US1628445 A US 1628445A
- Authority
- US
- United States
- Prior art keywords
- georges
- silver
- zelger
- emmanuel
- acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000002253 acid Substances 0.000 description 24
- 229910052709 silver Inorganic materials 0.000 description 14
- 239000004332 silver Substances 0.000 description 14
- GGCZERPQGJTIQP-UHFFFAOYSA-M Sodium 2-anthraquinonesulfonate Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)[O-])=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-M 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 238000006722 reduction reaction Methods 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 239000001828 Gelatine Substances 0.000 description 4
- VZJVWSHVAAUDKD-UHFFFAOYSA-N Potassium permanganate Chemical compound [K+].[O-][Mn](=O)(=O)=O VZJVWSHVAAUDKD-UHFFFAOYSA-N 0.000 description 4
- GRWZHXKQBITJKP-UHFFFAOYSA-L dithionite(2-) Chemical class [O-]S(=O)S([O-])=O GRWZHXKQBITJKP-UHFFFAOYSA-L 0.000 description 4
- 229920000159 gelatin Polymers 0.000 description 4
- 235000019322 gelatine Nutrition 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 230000002441 reversible Effects 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- KRVSOGSZCMJSLX-UHFFFAOYSA-L Chromic acid Chemical class O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 2
- ADZWSOLPGZMUMY-UHFFFAOYSA-M Silver bromide Chemical compound [Ag]Br ADZWSOLPGZMUMY-UHFFFAOYSA-M 0.000 description 2
- JVBXVOWTABLYPX-UHFFFAOYSA-L Sodium dithionite Chemical compound [Na+].[Na+].[O-]S(=O)S([O-])=O JVBXVOWTABLYPX-UHFFFAOYSA-L 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-M bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 2
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 description 2
- 239000004289 sodium hydrogen sulphite Substances 0.000 description 2
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 description 2
- 239000001119 stannous chloride Substances 0.000 description 2
- 229940013123 stannous chloride Drugs 0.000 description 2
- 235000011150 stannous chloride Nutrition 0.000 description 2
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
- G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
- G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
- G03C5/50—Reversal development; Contact processes
Definitions
- the known method for obtaining direct positives or counter-types by reversal consists in a thorough development of a photographic plate. and in then treating 1t in a 5 bath which dissolves the silver of the image, and lastly in reducing by a developer the bromide of silver which remains unchanged.
- the ohtainment of the first and thorough development requires a very strong developer. and it is thus necessary to operate as a rule in a very alkaline medium.
- the baths for dissolving the silver based upon potassium permanganate and 'sulphurlc or chromic acids, etc. arealways strongly acid. Inversely, the second development,
- the applicant has found that this alternation of media, which are alternately strongly acid and basic, to which the gelatine is subjected, tends to alter it considerably, chiefly in warm weather; and 1t 19 especially the operation in the last developing bath which is to be feared inthls respect.
- the present invention consists in substituting for the second development a chemical reduction. partial or complete, of the silver bromide, by means of baths which have not the nature of developers but which are formed of substances reducing the sllver salt in an acid medium. In this manner an alternation between acid and basic substances is obviated, and after the treatment in the first developer. the gelatine of the print is treated only in an acid medium.
- a photographic process for obtaining direct positives consisting in effecting a first development. then dissolving in an acid bath the silver of the image thus obtained, and
- a photographic process for obtaining direct positives consisting in efi'ecting a first development, then dissolving in an acid bath the silver of the image thus obtained and then efiecting the final reduction of the remaining silver salt in an acid bath containing substances capable of reducing said silver salt in an acid bath even without any exposure to light.
- a photographic process for obtaining direct positives consisting in effecting a first development, then dissolving in an acid bath .5
Description
Patented May 10, 1927.
UNITED STATES PATENT oFricE,
GEORGES EMMANUEL ZELGER, OF VINCENNES, FRANCE, ASSIGNOB TO PATHE CINEMA,
ANGIENS ETABLISSEMENTS PATHE FRERES, OF PARIS, FRANCE.
PROCESS FOR OBTAINING DIRECT POSITIVES BY REVERSAL' No Drawing.
The known method for obtaining direct positives or counter-types by reversal, consists in a thorough development of a photographic plate. and in then treating 1t in a 5 bath which dissolves the silver of the image, and lastly in reducing by a developer the bromide of silver which remains unchanged. The ohtainment of the first and thorough development requires a very strong developer. and it is thus necessary to operate as a rule in a very alkaline medium. But the baths for dissolving the silver. based upon potassium permanganate and 'sulphurlc or chromic acids, etc. arealways strongly acid. Inversely, the second development,
effected in a developer. is alkaline.
The applicant has found that this alternation of media, which are alternately strongly acid and basic, to which the gelatine is subiected, tends to alter it considerably, chiefly in warm weather; and 1t 19 especially the operation in the last developing bath which is to be feared inthls respect. The present invention consists in substituting for the second development a chemical reduction. partial or complete, of the silver bromide, by means of baths which have not the nature of developers but which are formed of substances reducing the sllver salt in an acid medium. In this manner an alternation between acid and basic substances is obviated, and after the treatment in the first developer. the gelatine of the print is treated only in an acid medium.
, This avoids the serious drawback above men- ,"tioned.
" 1 The alkaline hydrosulphites, with the addition of a weak. acid, the acidulated Application filed April 14, 1923, Serial No. 632,135, and in Franee'Februar -y 16, 1923- hypoph0sphites,-- stannous chloride, etc. are adapted for this last operation.
By way of example, use can be made of the following li'ath: water. 1 litre, sodium bisulphite liquid, cubic centimeters, sodium hydrosulphite, -10 grammes.
Having" now described my invention. what I claim as 'new and desire to secure by Letters Patent is:
1. A photographic process for obtaining direct positives consisting in effecting a first development. then dissolving in an acid bath the silver of the image thus obtained, and
then effecting the final reduction of the remaining silver salt in a non basic bath containing substances capable of reducing said silver salt in an acid bath even without any exposure to light.
2. A photographic process for obtaining direct positives consisting in efi'ecting a first development, then dissolving in an acid bath the silver of the image thus obtained and then efiecting the final reduction of the remaining silver salt in an acid bath containing substances capable of reducing said silver salt in an acid bath even without any exposure to light.
3. A photographic process for obtaining direct positives consisting in effecting a first development, then dissolving in an acid bath .5
the silver of the image maining silver'salt'in a nonba sic bath con taming 1n proportion: Water lilrtre, sodiu thus obtained and? then effecting the final reduction of the rebisulphite liquid 50 cubic centimeters, sodium 7 hydrosulphite 10 grammes. y
In testimonyi whereof I have signed m name to this specification. T
GEORGES-EMANUEL Z ELGER.
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US1628445A true US1628445A (en) | 1927-05-10 |
Family
ID=3412519
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US1628445D Expired - Lifetime US1628445A (en) | Georges emmanuel zelger |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US1628445A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2984567A (en) * | 1957-11-29 | 1961-05-16 | Eastman Kodak Co | Method for elimination of reversal reexposure in processing photographic films |
-
0
- US US1628445D patent/US1628445A/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2984567A (en) * | 1957-11-29 | 1961-05-16 | Eastman Kodak Co | Method for elimination of reversal reexposure in processing photographic films |
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