According to the folks at Photographer's Formulary, they are selling a new improved version of the Wimberley WD2D formula. They sent me some to test, but what I really want to know is how does this formula differ from the old one? I know the original formula specified benzotriazole, and various people have recommended that it be omitted. WD2D is very similar to PMK, except it uses sodium carbonate instead of sodium metaborate as the alkaline agent.