Where does US pigments natural iron oxide fit into this?
I agree with that I agree that one needs to be picky about one's glaze Ingredients, but how do you know where the best ones are? You think a company like Laguna would not be supplying second-rate materials, but obviously they are. I know you can run tests on everything, but that would be an overwhelming task. At some point you've got to figure out who you can trust and who you can't. Can we make a list of quality suppliers? If I understand right, we can put US Pigment at the beginning of that list. Who else can we add?