Glaze tests, Round 1

It occured to me I never got around to posting any pics from the glaze chemistry course over the last few weeks. So here’s my first homework assignment: three glazes mixed up based on limit formulas.


They’re a good illustration of how unpredictable glazes can be, and why potters spend so much time testing them. I was aiming for three light green glazes: one opaque and matte (I got clear satin), and two glossy, semi-clear with fun surface effects (I got one plain glossy clear, and one glossy semi-clear with fun stuff below the surface). And none of them are light green.

They all have the same colourant, 1% copper carbonate. The only difference between two and three is that two contains barium carbonate, and three contains zinc oxide.

As you can see, colour isn’t just determined by your colourants; it’s also heavily influenced by your base. And while some ingredients tend to have certain properties (barium carbonate is supposed to funkify things), those properties only emerge if said ingredient plays well with everything else in the base.

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