A couple of months ago I mixed a rather large amount of ferric oxalate solution for kallitype and palladium printing, anticipating that I would use all of it within a relatively short period of time. Well, things happened and I was delayed in making the planned kallitype and palladium prints, and now I am going to be doing carbon printing only until July. Question is, can I keep the ferric oxalate solution (25%) fresh by freezing? Any literature on this?