EP 0911687 A1 19990428 - Preparation method of morphologically homogeneous (111) tabular crystals rich in silver bromide
Title (en)
Preparation method of morphologically homogeneous (111) tabular crystals rich in silver bromide
Title (de)
Verfahren zur Herstellung von morphologisch homogenen silberbromidreichen tafelförmigen (111)-Kristallen
Title (fr)
Procédé pour la préparation des crystaux tabulaires (111) riches en bromure d'argent et morphologiquement homogènes
Publication
Application
Priority
EP 97203313 A 19971024
Abstract (en)
A method is disclosed for preparing an emulsion having grains rich in silver bromide in the presence of gelatin as a protective colloid in a reaction vessel wherein a yield of more than 250 g of precipitated silver nitrate per liter of reaction vessel mixture is attained, wherein at least 70 % of a total projected area of all grains is provided by ä111ü tabular grains having an average aspect ratio of more than 2:1 and an average thickness of from 0.05 up to 0.30 mu m and wherein a ratio by number of procentual amounts of hexagonal tabular grains to triangular tabular crystals present is more than 10:1, said method comprising following steps : preparing in a reaction vessel a gelatinous dispersion medium containing an initial amount of oxidized gelatin corresponding with less than 50 % of a total amount of gelatin used in the said method, and said dispersion medium having a volume of less than 2 liter per 500 g of silver nitrate to be precipitated; precipitating therein silver halide crystal nuclei by double-jet precipitation of an aqueous silver nitrate and an aqueous solution comprising halide ions, wherein less than 10 % by weight of a total amount of silver nitrate used is consumed; adding to said reaction vessel gelatin in an amount of more than 50 % of a total amount of gelatin used in the said method; growing said silver halide crystal nuclei by further precipitation of silver halide by means of double-jet precipitation of an aqueous silver nitrate solution and an aqueous solution comprising halide ions, wherein more than 90 % by weight of a total amount of silver nitrate is consumed, concentrating by ultrafiltration the said reaction mixture volume in the said reaction vessel obtained during precipitation growth steps.
IPC 1-7
IPC 8 full level
G03C 1/005 (2006.01); G03C 1/015 (2006.01); G03C 1/035 (2006.01); G03C 1/047 (2006.01); G03C 5/16 (2006.01)
CPC (source: EP)
G03C 1/0051 (2013.01); G03C 5/16 (2013.01)
Citation (search report)
- [E] EP 0843208 A1 19980520 - AGFA GEVAERT NV [BE]
- [A] US 5567580 A 19961022 - FENTON DAVID E [US], et al
- [A] EP 0697618 A1 19960221 - FUJI PHOTO FILM CO LTD [JP]
Designated contracting state (EPC)
BE DE FR GB
DOCDB simple family (publication)
EP 0911687 A1 19990428; EP 0911687 B1 20040714; DE 69729869 D1 20040819; DE 69729869 T2 20050519; JP H11223894 A 19990817
DOCDB simple family (application)
EP 97203313 A 19971024; DE 69729869 T 19971024; JP 30107298 A 19981022