When you look back at the ceramics produced over time and world wide, one technique keeps re-occurring, tin-glaze. What is so alluring about this method of finishing plain pottery?
Color. Not the color of tin-glaze, but the way it makes other colors pop. When fired, the tin-glaze provides an opaque white base for any other glazes that are applied. Each time this fact is discovered, a new name is applied to the process, usually the location or pottery where the new, colorful pottery comes from. Thus we have:
Without the white base provided by the tin glaze, the colors are applied directly to the clay and appear muddy. Some colors even disappear altogether, depending of the color of the clay being used. hus the popularity of tin-glazing.
With strong colors available, the decoration is usually also robust, leading to folk or “primitive” designs. These usually have great charm in addition to the bright colors, but they are not the elegant designs considered appropriate for the high and mighty. Thus, these products are used by common folk, the colors brighten their lives a bit and the decoration is appropriate. These factors are important in the continuing popularity of this kind of ceramics.
The basic process used by the manufacturers in each region are basically the same, and the same as the one used for fine porcelain. The most sophisticated process involves the following steps:
- The clay body is formed.
- The clay body is fired to bisque.
- The body is dipped in the tin glaze, usually inside and out. The glaze is absorbed into the bisque.
- Additional painting in one or more colored glazes is performed. These glazes also are absorbed into the clay body.
- A object is dipped into a clear glaze to provide the shiny surface.
- The decorated body is fired again, at which time the glazes and clay body vitrify into a single component.
- Luster, colored enamels or gilding are added to the decoration.
- A low temperature firing fused the final decoration to the object, if needed.
Not all of the pottery types listed above incorporate all these steps in their production at any given time. Experience in the manufacturing process and the economics of the time dictate which steps are skipped. The results therefore vary in technical excellence of the product as well as the proficiency of the painted decoration.
Metallic oxides provide the color under-glazes:
- cobalt oxide for the popular blue
- copper oxide for green paints
- iron oxide for brown
- manganese dioxide for purple-brown
- antimony for yellow
These are the colors that predominate is these types of pottery.
There are many people who collect some sub-set of these types of ceramics. The blue and white of Delftware has been popular ever since it first appeared, and has been copied almost as long. The Victorian era’s taste for Majolica has provided the 20th and 21st centuries with many forms, such as oyster plates and plant pots, to collect.
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Most of this material comes from
http://en.wikipedia.org/wiki/Tin-glazing
This and other Wikipedia pages have more information about these forms of pottery.
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Read more about porcelain collectibles.