As the days get longer, the number of weeks until the firing gets smaller. It was very interesting listening to Paula Artal-Isbrand, our guest speaker for the week. She had been working with red- and black-figure pottery and experimenting with slip by using modern technologies to study the varying processes. Her description of the firing process was similar to Professor Walton’s last week, with the oxidation phase, the reduction phase, and the second oxidation phase. We were also introduced to a process called Reflectance
Transformation Imaging (RTI), during which multiple photos of one object under different angles of raking light are taken to observe the topography of the surface and see the raised relief lines and indented sketch lines. The sketch lines were particularly helpful to us, because the idea of painting images with no sort of outline or sketch seems practically impossible to tackle without mistakes. Artal-Isbrand had also been experimenting with potential tools for slip, and found that a brush made with one to three hairs created relief lines that were closest to the ones observed with RTI. We ourselves had made versions of these brushes, but had trouble creating the exact sort of raised lines and keep them after burnishing.
Getting back into the workshop at Clayworks after a quick visit with our kiln firing downstairs, we were greeted by the sight of the two large test tubes of our slip that we made in week 5. One, with the weaker deflocculant Epsom salt, had separated into two layers, whereas the slip with the aggressive deflocculant sodium silicate had separated into the correct three layers. These three layers are: mostly water on top, heavy clay sediment on the bottom, and slip in the middle, as we learned in week 5’s lesson. In order to get to the slip that we use on the vessels, however, we had to siphon it out using thin tubes and gravity—done by sucking the slip out. It didn’t taste spectacular, but recreating the ceramics means recreating the experiences.