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US 5,472,838 AGranted
Process for the production of a silver halide emulsion
AssigneeAgfa-Gevaert
InventorsGunter Helling, Klaus Wagner
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AssigneeAgfa-Gevaert
InventorsGunter Helling, Klaus Wagner
Estimating the term…
Silver halide emulsions with tabular grains showing increased aspect ratio are produced by adding to the precipitiation vessel a compound of the formula I: ##STR1## in which R.sub.1 means H or optionally substituted alkyl, aralkyl or cycloalkyl R.sub.2 means H or optionally substituted alkyl, aryl or aralkyl or a polymer chain R.sub.3 means H, OH, alkyl, aryl, aralkyl, halogen, NHR.sub.4, O--CO--R.sub.4, O--CO--NHR.sub.4 or an optionally substituted oxazoline ring R.sub.4 means optionally substituted or alkyl, aralkyl or aryl m means 2 or 3, n means 2 to 10,000, or a compound of the formula II ##STR2## in which R.sub.1, R.sub.3, n and m have the meaning stated above and may be identical or different and R.sub.5 means optionally substituted alkene, arylene, aralkene or a polyaddition, polycondensation or polymerisation chain.
Process for the preparation of a silver halide emulsion by reacting an alkali halide and silver nitrate in aqueous solution in a reaction vessel in the presence of a binder characterised in that a compound of formula I or II is added to the reaction vessel before the precipitation of the silver halide starts ##STR9## in which R.sub.1 means H or alkyl, aralkyl or cycloalkyl
Dependencies are inferred from the claim text.