#glaze technology

Insides! The bottoms range from almost crater texture, jewel green pools, and deep reflective mirrors.

Excellent glaze chemistry analysis of Shino glaze in Japan.

pastel flowers of spring looking great with my copper patina glaze :) 1200 mid fired cool ice porcelain.

A line test of neph syenite in the glaze i've been testing. Gotta do a proper one with proper test tiles!

Group photo!

Good luck lovelies.

Of all the styles of decoration created by the Chinese potters of the Song period, one of the most remarkable and intriguing is one that is found on certain black Jizhou bowls in Jiangxi province. A delicate image in yellow ochre shows the form of a leaf even down to its fine veins, even showing insect damage. For a long time, only the copius work by Cécile and Michel Beurdeley : « La céramique chinoise, le guide du connaisseur » (on page 139 as I remember !) showed a beautiful example of this style. This bowl, famous in Japan, and classified as « Important Cultural Property », is currently preserved in the Museum of Oriental Ceramics in Osaka, a gift of Sumitomo group after belonging to the Maeda family for many years. In 1987, while researching black glazes, composed of wood ash and clay containing iron oxide, I was certain that the colour of the image could be explained by the extra ash added by the leaf itself which after calcination, leaves the image of a real leaf on the glaze. On my first attempt, I was encouraged by finding formless yellow spots on a black bowl. Heartened by this, I carried on, sure that I was working in the same direction as the ancient chinese potters. After several theories and many failures, I had my first success in 2007. It was better than that, since a lucky chance gave the solution to the enigma. Over the very edge of the bowl, the stem of a leaf hung suspended in space. Between my fingers it turn to dust. It had not melted ! I would find the answer in an old book on plant chemistry by Mr. Marchal : « The biological purpose for leaves falling is so that the plant can rid itself of unwanted minerals ... which is why the fallen leaves are rich in lime, silica and iron ... while simultaneously other compounds such as phosphates and potassium salts pass back to the plant leaving small quantities in the leaves ». Analysis of leaves carried out by Emile Wolff and continued by Robert Tichane in his work « Ash Glazes » confirms that in autumn, leaf ash can be composed of nearly 80% calcium and silica, making the mixture resistant to the temperature of stoneware firing. Fortunately, the calcium and silica in the leaf, find the third element in the glaze, aluminium oxide. This allows the eutexia and the melting of the elements. Nature is therefore in charge and I will have to wait patiently until autumn to stock up on leaves. From October onwords my friend Nicole will have to cycle up and down the numerous lanes of the beautiful Fouesnant countryside. Daily, she will choose the most suitable leaves just before they rot on the wet ground. Having sent the details of my research to Brother Daniel de Montmollin, he very kindly replied that he had greatly appreciated « The Beautiful Image of the Resurrection of a Dead Leaf ». Yvon Le Douget Site : ledouget.fr/