A Terra Sigillata Technique for a Textile-Inspired Bowl

Wheel Throwing, Altering, and Applying Terra Sigillata

Terra Sigillata Technique

Terra sigillata pottery has been around since the ancient Greeks created their famous black and red pots, but it is certainly not “getting old.” Contemporary potters, such as Sharon Alpren, are making exciting and beautiful terra sigillata ceramics to this day.

In today’s post, an excerpt from the November 2016 issue of Ceramics Monthly, Alpren shares the terra sigillata technique she uses to make her gorgeous textile-inspired bowls. – Jennifer Poellot Harnetty, editor.

P.S. Learn how Sharon Alpren switched from a career in retail buying and textiles to one as a studio potter in Melbourne Australia. Read about Alpren’s experiences and see more of her work in in the November 2016 issue of Ceramics Monthly.

Throwing and decorating a bowl

I throw my Bedrock series bowls on the wheel using a richly colored and highly textured stoneware clay (A). After leaving the bowl to firm up for a couple of hours, so it is no longer wet and sticky but still very pliable, I then alter the bowl to give it a more organic shape by squeezing and stretching the clay between my hand and a wooden kidney tool (B).

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Terra Sigillata Technique


Terra Sigillata Technique

When the bowl is completely dry, I use a sgraffito tool to incise the lines that will later be filled with black inlay slip (C),  then apply an undercoat of white terra sigillata, rubbing it into the textured clay with a soft rag (D). The clay is very dark when fired and the colors require a white undercoat to show up.

Terra Sigillata Technique

Terra Sigillata Technique

The colored terra sigillata is brushed on next (E). Terra sigillata can be rather thin so it may take up to three layers or more to build up sufficient color. I burnish the terra sigillata with a soft rag so that the texture of the clay comes through.

Terra Sigillata Technique

Terra Sigillata Technique

After bisque firing, I inlay a black engobe into the incised lines and sponge off the excess (F). Then, when the piece is bone dry, it is fired in a gas kiln to cone 9, in medium reduction.

**First published in 2016.
  • Beverly H.

    Red terra sig can be made with Red Art clay. White terra sig can be made with white Ball clay. Mason stains, oxides, or carbonates (the finest particles, best for polishing or burnishing) can be used to color the white terra sig.

  • Reader L.

    One can use ceramic pigments or stains to add colour, but the percentage must be higher than when they are used to colour glazes.

  • Reader L.

    could this be done with an electric kiln? after the bisque firing add the black engobe slip and re-fire?

    • Aaron K.

      I believe because she is using a reduction firing some of the gases and other elements leave a sheen on pieces.

  • Linda L.

    Sharon, can I ask what you use to colour the terra sigilata? I’ve just returned to ceramics after a long break and have been exploring terra sig. I’ve made a batch and am happy with the satiny surface it produces but don’t know what to use to colour it. I live in regional Vic so would probably buy supplies from the same places as you.

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