| abstract |
REACTIVE N-SUBSTITUTED, CYCLOAMMONIUM QUATERNARY SALTS, WHEREIN THE N-SUBSTITUENT INCLUDES ALKYL RADICALS WHOSE TERMINAL CARBON ATOM IS ADDITIONALLY SUBSTITUTED WITH AN ACYL RADICAL SUCH AS A FORMYL RADICAL, AN ACETYL RADICAL OR A BENZOYL RADICAL ARE USEFUL NUCLEATING AGENTS IN DIRECT POSITIVE PHOTOGRAPHIC EMULSIONS. |