"Dennis Boone" wrote in message
...
Then it says After toning wash thoroughly Na sulphite 10%, prevents
posttoning.
Could someone please explain the "Na sulphite10%" as I do not
understand.

Presumably sodium sulfite. http://en.wikipedia.org/wiki/Sodium_sulfite

Photographer's Formulary appears to stock the stuff:

http://stores.photoformulary.com/-st...ley/Detail.bok

De

Thanks to all for your reply's, and your knowledge