This week I visited a gallery, Spindrift, in Portscatho, which is local to me in Cornwall. They have a good selection of ceramics, much of it quite functional and very lovely. Most of it by local artists. So I reached up to a high shelf and pointed to a pair of lovely green bottles. They had a generous, welcoming shape but what intrigued me was the surface finish. At first sight I thought that a crackle glaze might have been used, but that didn’t look quite right. Were they raku fired? No, the mottled effect was the colour IN the lines, which was a really lovely green. What secrets were hidden here?
I commented on the vessels and asked if I might lift one down. ” Those?” uttered the owner of the gallery with a slight twinkle in his eye, “By all means, but they are not for sale. I bought them in a well known DIY shop a few years ago. They cost £8:00 and I wanted them to hide my wifi.” Oh how embarrassing! I am supposed to know about ceramics now. I have a diploma so I must do, right? Wrong! I know nothing except how much I don’t know!
In fact I was reassured later in my conversation with the gallery owner, Fred, who told me that I was by no means the first person to be taken in by the vases. He told me about the people who ‘knew it all’ and who would come in and tell their companions all about the techniques used and be completely incorrect about their theories. In fact, I discovered, egg shell had played a crucial role in the creation of the surface. I rushed home to look it up.
It transpired that this is done by a type of inlaying by the Chinese. I found a U-tube video showing me how to do it and all sorts of images and instructions. It got me wondering though. How else might egg shell have been used in ceramics? It is a great source of calcium which I know to be a secondary flux. Fluxes are used to lower the melting point of the glass formers in a glaze. Secondary fluxes only become active at higher temperatures and within that higher range calcium is a fairly useful addition to many a glaze recipe so . . . . what would happen? I wonder . . . . . I feel some trials coming on as soon as I get back from my self imposed holiday from the studio. Watch this space . . . .