Speaking of glazes: I’ve been learning that the discipline of ceramics involves many variables, and some of the variables are less constant than I’d expect. In the discipline of painting, when I use up paint and I need to buy replacement tubes, they are very consistent in formulation so they are almost never perceptibly different. In ceramics, due to weight, volume, and cost issues we mix most of our glazes ourselves. This introduces a lot more human error compounded by potential supply line vendor changes in the ingredients and user contamination. To continue the comparison, it’d be like if I switched brands and sometimes even types of paint and expected continuity!
To state it simply: I’ve learned that when a bucket of glaze is gone and we remix it, I cannot expect the same aesthetics or behavior from the new glaze as from the old, even if they are purportedly the same. In some ways this is disconcerting, of course. But it is also a real opportunity, and it adds some exciting pressure and novelty into the glazing process. The novelty is self-explanatory; the pressure comes from if you want consistency since you only have as long as those buckets last for the desired effects to relatively predictably result.
Below is how Cone 6 Larry’s Black under Iron White looked with the bucket of Iron White that we were using last year.
You can see that the Iron White behaved in a very glossy way, was relatively thin at one coat but varied in thickness dependent on number and types of application coats with opacity ranging from translucent to decently opaque. At its most opaque, it was white. The Larry’s Black underneath went to a glossy and stable spectrum of various values of blue dependent on the application thickness of both colors.
We used up that bucket of glaze a few months ago, and the new Cone 6 Iron White appeared. Below are two new pieces that use Green Tweed, Larry’s Black, and the new mix of Iron White.
This Iron White is thicker at one application coat, a little yellower, and more opaque and matte. It also interacts quite differently with Larry’s Black. The matte-over-gloss effect causes the Iron White to crater and blister atop Larry’s Black; you can see it does not do that over Green Tweed as Green Tweed is itself more of a matte glaze.
Cratering and blistering are frequently considered “glaze defects,” but I enjoy the texture that some “glaze defects” provide - if you review my body of stoneware ceramic work you’ll notice that I am drawn to crawling as well.
Since these were my first pieces with the new bucket of Iron White, I didn’t know about this new interaction yet - I was expecting glossy results aligned to that first batch above. Now that I know, I’ve glazed a bunch of new ceramics with this cratering/blistering effect in mind, and they are waiting in the kiln until it’s filled up and ready to fire. I’m excited to see them come out!