| abstract |
Oxonol dyes of the formula I <IMAGE> (I) in which R1, R2 mean an optionally substituted furyl or thienyl group, R3, R4 mean an aryl group substituted with at least two sulpho groups, L means CH or CR5, R5 means C1-C4 alkyl and n means 0, 1 or 2, give rise in a photographic material to an improvement in sharpness. |