View Larger Image This wheel-thrown porcelain vase was carefully incised and fired to Cone 10 in reduction, by Ann Selberg.

April 9, 2008

Carving with Care: Tips for Incising and Glazing Pottery

by Ann Selberg | Read Comments (0)

I am a big fan of old buildings. I love the architectural details that are so often left out in more contemporary structures. Successfully incorporating architecturally inspired details into my clay work is something I have always wanted to do, but still have not quite worked out as well as I’d like. Portland, Oregon, ceramic artist Ann Selberg, however, does this extremely well. Her work is inspired by the architectural terra cotta and metal ornamentation on the buildings by Frank Lloyd Wright and Louis Sullivan, which she passed on daily walks while living in Chicago a few years back. Today, Ann shares her techniques for creating her precisely carved, beautifully glazed, architecturally inspired pots. - Jennifer Harnetty, editor.

Incising suits my temperament. It satisfies my love of pattern and order. It is subtle.

Originally all of my designs were done freehand on the pot. Some of my art training precedes the use of computers for graphics and signage. I was taught to do layout by hand. I became a competent calligrapher. The concept of “eye-balling it” rather than precisely measuring, and the calligrapher’s understanding that in drawing a line one also creates space around the line and relationships to nearby lines, are with me during incising. Some ideas do require pencil sketching first.

I use a small, u-shaped trimming tool while the clay is leather hard. Some experimentation is involved in determining the proper depth of the incised groove. Designs that call for fluid hand movement help necessitate even depth and smooth line work. I’m always thinking of how my hand will move across the pot with the tool, as well as how the shape of the specific pot is enhanced by incising.

Because the sole decoration on my pots is relief created by incising, breaking glazes set off the patterns best. A matt or semi-matt surface suits the character of the pieces. Each pot is dipped in a single glaze.

A narrow, deep groove will cause air bubbles to form when the pot is dipped in glaze. If the mark is too shallow it will be lost in a coat of glaze. Horizontal lines on a piece tend to gather bubbles, so these pots should enter the glaze diagonally.

It has always been my inclination to avoid gauges and scientific equipment in relation to pottery making. There is certainly a sense that some of the mystery and the sport will be lost. When the old-fashioned method of sticking a hand in the glaze to test for thickness could not satisfy my need for consistent results with the incising, an $18 investment in a hydrometer helped me find the proper glaze consistency, where patterns show through the glaze and there is still sufficient glaze to create a pleasing surface. This little instrument proved to be worth its weight in cobalt carbonate. It is a sealed blown-glass tube weighted on one end so it floats upright in the glaze. It has a graded scale on the side that is calibrated to indicate specific gravity of a liquid at 60°F (15.5°C). Specific gravity is the measure of the density of a given substance compared to the density of the same volume of water. For my glazes, a specific gravity between 1.6 and 1.65 is a good place to start. It seems that each glaze has a slightly different ideal specific gravity, which also may vary with a change of clay body.

To see more images of Ann Selberg's work visit www.annselberg.com.

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