RE: clearing dichromate stain
Charles, you can buy Sodium *meta*bisulfite too. See this: http://wiki.silvergrain.org/wiki/index.php/Bisulfite "...When metabisulfite is dissolved in water at a reasonably low concentration, one mole of metabisulfite and one mole of water form two moles of bisulfite.." 1 mole Na metabisulfite = 190.109g 1 mole Na bisulfite = 104.062g Therefore, to make a 1000ml 5% Na bisulfite equivalent solution with Na metabisulfite you need: 50g * ( 190.109 / 104.062 / 2 ) = 45.67g Na metabisulfite. In other words, you can just substitute metabisulfite in place of bisulfite - for the purpose of clearing gum prints it won't make any difference... Regards, Loris. -----Original Message----- From: ryberg [mailto:cryberg@comcast.net] Sent: 13 Aralık 2006 Çarşamba 01:35 To: alt-photo-process-l@usask.ca Subject: Re: clearing dichromate stain Katharine, I just remembered that the big beer and wine making supply store sells both potassium and sodium bisulfite. It is a quick trip by car from here. Perhaps tomorrow. Yours Chuck
|