Ballasted optical brighteners

摘要

A ballasted water-soluble optical brightener of formula (I) is new. Polymer = a gelatin residue; M = a cation; X = a gp. which can undergo nucleophilic displacement; and Z = -N(R2)-R1 or -O-R3: R1 and R2 = H or an aromatic gp. opt. substd. by one or more gps. unreactive to X; and R3 as for R1 other than H. Also claimed is a photographic element contg. the optical brightener (I) in at least one layer.