P.S. to the Kaltbeize AL mordant

I received a reply today from Karin Tegeler, the supplier of this mordant, and it would seem that I had understood perfectly the information supplied with it. (As all the information was in German, I wanted to be sure that my knowledge of German had been adequate.) The main advantage of this form of alum mordant would seem to be that it can be applied cold whereas, according to the comparative information supplied with this Kaltbeize, the more common alum mordants, such as alum sulphate and potash alum, cannot. (However, my experiments and the experiences of other dyers would suggest that alum sulphate can in fact be successfully applied without heat.) The information sheet suggests that each solution can be used at least 6 times before it is exhausted and that 100gms mordant powder should mordant about 1.5 kilos of fibres. I’m afraid I still don’t know why the ratio between the amount of water added and the quantity of mordant powder used seems to be the crucial factor when measuring quantities. Nor do I know whether its chemical name is aluminium formate, although further searches online for “aluminium formate mordant” seem to suggest that it must be.  But Frau Tegeler confirmed that a Kaltbeize mordant solution can continue to be used until there is insufficient liquid left to cover the fibres. However, I still think that 100gms/5 litres would probably be exhausted after 1.5 to 2 kilos of fibres had been mordanted in it, even if the level of the liquid was still fairly high. Frau Tegeler also told me that one customer had left her wool in the cold mordant bath for a year before getting round to dyeing it, but when she did dye it the results were excellent. Anyway, I think I should now stop asking questions and just enjoy using this mordant.