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GLAZES
Our glazes followed the pattern set by the development of
the body formulations. We began with earthenware glazes based on the imported
materials available to us at the time. We had a brown (iron) glaze and a white
(opacified) glaze. Variety was created by extensive use of slips coloured by
oxides of iron, cobalt, manganese and a black when all three were mixed
together. These were used as a background for sgraffito decoration under the
white glaze. We also in those days spent some time on developing a copper red
glaze with varying results.
With the development of stoneware bodies our interest in celadon glazes based on naturally occurring materials overtook the interest in copper red. We spent a great deal of time on celadons. One advantage was the fact that they happened to help to lighten our colours at a time when we did not always have a ready source of opacifier to make a reliable white glaze. In the early days the stoneware body was still underdeveloped and too dark and coarse-grained to show the celadon to advantage. We used a white slip either over surface carving or directly over a body darkened by iron to facilitate the creation of dark lines through the glaze. To create variety and visual interest we would make a yellow or a blue celadon in addition to the more common pale green. The high point of our celadon glaze development came with Donald's breakthrough of a porcelain body that showed the celadon glaze at its best. Unfortunately, the process involved in preparing a batch of porcelain from local materials using currently available equipment placed porcelain preparation in the realm of "something we will do again one of these days when we have the time".
We have always had at least one iron glaze, a shine white, an off-white matte, a celadon and an attractive blue. These glazes are used with slips, brushed on stains or oxides and in double glazing. In addition, a fair number of pieces have been glazed inside but unglazed on the surface and finished by carving or brushed on stains. The Hodges body in particular is very attractive unglazed especially with occasional ash falls on the surface. With the advent of slip casting and increased production glazes became standardized and those glazes (however attractive) which were problematic fell from favour. |
An offshoot of the development of
celadons is the Chinese type glaze called "chun", an opalescent blue that is
very attractive. It came about by accident. One day we took a small ashtray from
the kiln expecting to see a celadon and saw instead an amazing semi opaque blue
with almost purple highlights. It took us a while to figure out that it was a
result of the use of ash in the glaze as a last minute substitute for whiting.
Donald was able to recreate the effect and the "chun" became a standard for a
number of years. We discontinued its use when we became tired of the effect of
hard settling that the ash caused. We also had to be very careful not to pour
water off the batch as we would loose the soluble component of the glaze thus
altering the composition and therefore the effects. In any case Donald had by
then created another blue glaze based on titanium that became as fascinating to
work with.