So these glazes were my second attempt at iridescent surfaces. I tried some copper, upped the manganese in several glazes, and also tried granular manganese, granular magnetite, and granular ilmenite. The Fake Mashiko turned out really nice, not at all iridescent, but nice.
One thing to note is the all of the tiles on the left were from firing #38, which was a small test gas kiln. It wasn’t a very good firing to say the least. The tiles on the right were from firing #40, which was an extremely long, extremely hot firing. The schedule was something like 4 hours between cone 7-8, then about 5 hours between 9-10, an hour to cone 11, and another 2 hour soak around cone 12. Pretty extreme for a gas kiln, I think. On the other hand, that’s nothing compared to some Anagama firing schedules.