Quote Originally Posted by Photo Engineer View Post

My literature reports that there have been explosions associated with working with Metabisulfite due to its strong reducing power. I would prefer to work with sulfite myself.

In our developer applications Metabisulphite is perfectly safe. Over the years I've used many metric tonnes, I'd get through 25kg every couple of days and we were adding it to Aqua Regia (Nitric & Hydrochloric acid) to generate SO2.

Home winemakers regularly use Metabisulphite in their kitchens, either as a powder or as Camden tablets.

Metabisulphite is also used in ID-13, D153 and equivalents, the Caustic Hydroquinone graphic arts developers