Shino… Hard to control, lovely to hold



I was exposed to Shino glazes in January, 2002 at the Fitchburg (Massachusetts, USA) Art Museum. Friends and fellow potters attended an opening reception of "American Shino: The Glaze of a Thousand Faces “ at the museum where I learned of Shino for the very first time.  I learned that it was a family of glazes that had been developed in Japan during the late 17th century, but then had fallen into obscurity. In 1974, a student, Virginia Wirt, a student at the University of Minnesota, developed a glaze formula that mirrored the Japanese Shino affect.  This formula became known as American Shino and has provided the foundation blocks for many variations of Shino used by potters today.  

After attending the event, my friends and I put into motion plans to purchase a gas kiln so we could experiment with reduction gas firing and Shino glazes.  Shino itself is considered a very finicky and unpredictable glaze.  I would never boast that I have “conquered” the glaze.  That would be foolish.  But over the past ten years of studying, reading, experimenting and firing, I have a much better understanding of the glaze.

The glaze I use is called carbon-trapping Shino.  Carbon-trapping is a technique to trap carbon under the glaze.  Carbon is created by starving the kiln of oxygen thus creating a smoky/sooty environment in the kiln.  At the precise time that the glaze melts the carbon will be trapped and sealed under the glaze.  If the kiln is heavily reduced, the finish on the ware will be black to grey. If the kiln is taken out of reduction too early (and returned to an oxidation environment) the carbon will be burned off and no carbon will be trapped. The ware produced if carbon is not trapped could be all white, or have some flashes of orange, or be all orange.

The “holy grail” of carbon-trapping is to trap some carbon, but burn off the rest to achieve a piece that has black, grey, tan, orange and white hues.  In one kiln load, one might have pieces that display all of these colors on a few pieces and just one of these colors on others.  In my kiln, the position of the piece inside the kiln (bottom, middle, top) will also affect the finished color.  Parts of the kiln fire hotter than others and will affect the finished piece.  

The picture below shows a good example of the color variation of Carbon-trapping Shino.



No matter the finished color, Shino fans know that the piece they may treasure is one-of-a-kind that is not easily reproduced.  Shino just is not that predictable.

As a side note, the inside of Shino glazed teapots will not exhibit any carbon- trapping no matter how heavy the reduction is during the firing. 

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