Polymeric optical filter agents and photographic products and processes containing same

摘要

Polymeric optical filter agents and photographic products and processes using same are disclosed. The polymeric optical filter agents are pH-sensitive optical filter agents comprising polymeric backbone units having the following hydrazone moiety: <IMAGE> where R is a group which can provide a double bond for conjugation with the <IMAGE> portion of the moiety to provide light-absorbing capability for the agent at a pH above its pKa, and X represents a substituent of R providing at least one electron-withdrawing group. The polymeric pH-sensitive optical filter agents have a highly colored light-absorbing form at a pH above the pKa and are substantially non-absorbing at a pH below the pKa. The polymeric optical filter agents are useful in photographic film units and processes for the protection of photoexposed photosensitive elements against the occurence of fogging during in-light development.