GB1426431A - Development of direct-positive silver halide elements - Google Patents

Development of direct-positive silver halide elements

Info

Publication number
GB1426431A
GB1426431A GB774372A GB774372A GB1426431A GB 1426431 A GB1426431 A GB 1426431A GB 774372 A GB774372 A GB 774372A GB 774372 A GB774372 A GB 774372A GB 1426431 A GB1426431 A GB 1426431A
Authority
GB
United Kingdom
Prior art keywords
development
silver halide
direct
emulsion
maximum density
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
Application number
GB774372A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Agfa Gevaert AG
Original Assignee
Agfa Gevaert AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to BE795336D priority Critical patent/BE795336A/en
Application filed by Agfa Gevaert AG filed Critical Agfa Gevaert AG
Priority to GB774372A priority patent/GB1426431A/en
Priority to CA163,406A priority patent/CA998871A/en
Priority to JP1783873A priority patent/JPS4890741A/ja
Priority to FR7305254A priority patent/FR2172253B1/fr
Priority to DE19732307480 priority patent/DE2307480A1/en
Priority to US05/563,397 priority patent/US4081281A/en
Publication of GB1426431A publication Critical patent/GB1426431A/en
Expired legal-status Critical Current

Links

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
    • G03C1/00—Photosensitive materials
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/485—Direct positive emulsions
    • G03C1/48515—Direct positive emulsions prefogged

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)

Abstract

1426431 Photographic direct-positive image development AGFA-GEVAERT 12 Feb 1973 [18 Feb 1972] 7743/72 Heading G2C A direct-positive image is produced by imagewise exposing a photographic material comprising at least one direct-positive silver halide emulsion layer containing electron-traps and uniformly fogged radiation-sensitive silver halide grains and developing the exposed emulsion using a silver halide developing agent, the degree of fogging of the grains being such that a test portion of the grains when coated as an emulsion on a support to give a maximum density of at least 1 upon processing for 6 minutes at 20 C in a developer comprising 2.5g N-methyl-p-aminophenol sulphate, 30g anhydrous sodium sulphite, 2À5g hydroquinone, 10g sodium metalorate, 0À5 g KBr and water to make 1 litre has a maximum density which is at least 30% greater than the maximum density of an identical coated test portion which is processed for 6 minutes at 20‹C in the above developer after being bleached for 10 minutes at 20‹C in a bleach composition comprising 50mg KCN, 3À47 ml glacial acetic acid, 11À49g sodium acetate, 119mg KBr and water to make 1 litre, and development being effected using a developer composition or a development activating composition which is free of halide ions. The emulsion may be of the type which comprises electron traps by the presence in the emulsion of an electron accepting or desensitizing compound. The silver halide grains may have in their interior centres promoting the deposition of photolytic silver. The material may be one that is described and claimed in U.K. patent no 1416996. Development may be effected using a viscous processing composition comprising a thickening agent (see Ex 5), or using a synergistic combination of hydroquinone and N-methyl-p-aminophenol sulphate or 1-phenyl-3-pyrazolidinone, or ascorbic acid and 1-phenyl-3-pyrazolidinone. The material may contain a colour coupler (see Ex 4) and the development may comprise colour development. The maximum density obtainable by a given development of direct-positive images formed with silver halide grains having a low degree of fogging can be increased by this process.
GB774372A 1972-02-18 1972-02-18 Development of direct-positive silver halide elements Expired GB1426431A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE795336D BE795336A (en) 1972-02-18 DEVELOPMENT OF PHOTOGRAPHIC DIRECT-POSITIVE EMULSIONS
GB774372A GB1426431A (en) 1972-02-18 1972-02-18 Development of direct-positive silver halide elements
CA163,406A CA998871A (en) 1972-02-18 1973-02-09 Development of direct-positive silver halide elements
JP1783873A JPS4890741A (en) 1972-02-18 1973-02-13
FR7305254A FR2172253B1 (en) 1972-02-18 1973-02-14
DE19732307480 DE2307480A1 (en) 1972-02-18 1973-02-15 DEVELOPMENT PROCESS FOR PHOTOGRAPHIC DIRECT POSITIVE MATERIALS
US05/563,397 US4081281A (en) 1972-02-18 1975-03-31 Developing low fogged, direct-positive silver halide emulsion with an energetic developer free from halide ions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB774372A GB1426431A (en) 1972-02-18 1972-02-18 Development of direct-positive silver halide elements

Publications (1)

Publication Number Publication Date
GB1426431A true GB1426431A (en) 1976-02-25

Family

ID=9838870

Family Applications (1)

Application Number Title Priority Date Filing Date
GB774372A Expired GB1426431A (en) 1972-02-18 1972-02-18 Development of direct-positive silver halide elements

Country Status (6)

Country Link
JP (1) JPS4890741A (en)
BE (1) BE795336A (en)
CA (1) CA998871A (en)
DE (1) DE2307480A1 (en)
FR (1) FR2172253B1 (en)
GB (1) GB1426431A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2557686B2 (en) * 1987-05-28 1996-11-27 富士写真フイルム株式会社 Direct positive color image forming method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1151363A (en) * 1965-04-30 1969-05-07 Agfa Gevaert Nv A Method of Producing Photographic Images
BE735930A (en) * 1968-07-11 1969-12-16

Also Published As

Publication number Publication date
CA998871A (en) 1976-10-26
FR2172253A1 (en) 1973-09-28
JPS4890741A (en) 1973-11-27
BE795336A (en) 1973-08-13
DE2307480A1 (en) 1973-08-23
FR2172253B1 (en) 1976-09-10

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Legal Events

Date Code Title Description
PS Patent sealed
435 Patent endorsed 'licences of right' on the date specified (sect. 35/1949)
PCNP Patent ceased through non-payment of renewal fee