History of Persian enamel pottery
During the Achaemenid period, enamel bricks with alkaline glaze were found in the Apadana of Susa, examples of which are now housed in the Louvre Museum in Paris.In Shush, there are two ways of decorating bricks, glazed silicone bricks with embossed designs and smooth surface bricks, which are executed exclusively by paint. These types of bricks have a combination of sand and lime mixture that each brick is formed in the mold with or without embossed decoration and goes into the furnace three times.
The first cooking is the making of a body, which today’s potters call biscuits. In the second cooking, enamel glaze was given and in the final baking, silicone glaze was added to it as a clear and smooth substance, painted with various oxides. Antimony lead was used for yellow, copper for green-blue, ferro-manganese for black and brown, and tin for matte glaze and white. Also in Persepolis Fars there is evidence of baked bricks with enamel-like glaze.
In the construction of enamel pottery, the clay paste changes. Clay is a juicy aluminum silicate clay from which pottery is made. Chinese soil or kaolin is the purest type of this soil. Other elements such as sodium, potassium, calcium, magnesium are considered impurities if they are associated with this soil.
Glass paste or porcelain is used to make enamel pottery. Enamel can only be used in the optimal condition and on a surface similar to glass. As soon as the enamel was developed on hard-coated pottery and often contained a high amount of kaolin, it became possible to make enamel glazed pottery. Mina was receptive to work. We see special examples in the Seljuk period. And probably around 495 to 545 AH in Kashan, where pottery was mixed with quartz and quartz, and pottery was created with a transparent body, which was as strong and durable as it should be, especially for carving the body.
The usual method of making enamel pottery attributed to Kashan and some others and some other central Iranian cities in the sixth century is probably rooted in the experiments of Neishabour and Samarkand potters who tried to have a role or glaze on the surface after baking the pottery. Cast them and reheat them in the oven to form a white pattern. A set of bowls with a date of 570 to 580 AH shows the peak of the evolution of this method. The above method is very complex and involves several times the kiln going to the furnace at temperatures usually 750 ، C, decreasing consecutively. Although the colors of glaze obtained from metallic minerals and oxides are very high, these pottery have always been problematic in matching their properties in the glazed kiln. The heat required to melt the glaze on the container either causes the paint to deteriorate or affects its strength. Compared to the late 6th century AH, Islamic potters clearly realized that if they wanted multi-colored painted objects, there were two ways.
They could either limit the coloring to a few colors that could withstand the heat needed to cook and glaze the dish in one step, or they could first glaze and cook the dish, then re-cook the dish over low heat with unstable colors. Use.