Bellini AntiFog Agent 5g (1-Phenyl-5-mercaptotetrazole)

Antifoggants are used to restore out of date paper. Papers containing incorporated developers usually keep less well than those without developers in them or papers that are coated on RC support. Bellini's Anti Fog is based on phenyl mercapto tetrazole. You add between 0.5 and 1 mg per litre of developer for a working strength solution.

All emulsions have a certain level of inherent fog. It is just that when fresh, the image comes up before the fog, while storage reverses this situation. Fog formation also often lowers contrast, and only sometimes will the use of an antifoggant restore that feature. Most always, you can expect a speed loss if you antifog the paper back. Something to consider when choosing a filter to use

Modern-day, Multigrade papers, containing multiple emulsions are often harder to control this way, as the two emulsions in them may not respond the same way to the antifoggant.

The molecular formula is C7H6N4S.