Quote Originally Posted by RalphLambrecht View Post

...sodium sulfite is a toner stop bath...
A bit of chemistry trivia. Brown toners are sulfide
toners. Polysulfides are used. Sulfur will dissolve in
sodium sulfide making a Polysulfide. Sulfur dissolves
also in sodium sulfite making Thiosulfate. So, a stop
of sulfite works because it ties up available sulfur.

It MAY be easy to make brown toner. I've some
sulfide solution ready. Wonder if P. Formulary carries
sulfur. Should be interesting and maybe rewarding
to experiment. Dan