Benzotriazole antifoggant, 1% solution

Description

A ready antifoggant solution for expired film and old paper. A few millilitres per litre of developer clear the grey veil and leave the image.

What it does

Benzotriazole restrains development where there is no latent image — which is exactly the fog an emulsion accumulates over years of storage. The image itself barely suffers: it develops faster than the fog, and the antifoggant separates the two in time.

How much to add

Start with 2–5 ml of the 1% solution per litre of working developer and add more if needed. An excess raises contrast noticeably and shifts paper tone cold — obvious at once on warm-tone papers.

Questions and answers

Will it rescue very old film?

Partly. It clears the fog but cannot restore lost speed — such film still has to be rated slower.