Glaze
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Glaze is a thin shiny coating, or the act of applying the coating. Glaze also means to install glass windows.
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Cooking technique
Glaze in cooking is a coating of a glossy, often sweet, mixture applied to food. Egg whites and icing are both used as glazes.
Painting technique
Glaze in painting is a transparent medium. Whatever is on the surface beneath the glaze shows through applied medium. A glaze changes the color cast or texture (gloss or matte, for instance) of the surface. For many centuries painters have applied glazes to their works.
When the technique is used for wall glazing, the entire surface is covered, often showing traces of texture (French brush, parchment, striae, rag rolling). Either oil-based or water-based materials are used for glazing walls, depending upon the desired effect. Kerosene or linseed oil may be used to extend the "open" or working time of oil-based glazes. Water-based glazes are sometimes thinned with glycerin or another wetting agent to extend the working time. In general, water glazes are best suited to rougher textures where overlaps of color are acceptable.
Scumble is a similar technique as glazing, except that coating is opaque.
Pottery glazes
In pottery, glazing is the process of coating the piece with a thin layer of a glassy material. After applying a glaze, the pottery is fired, and the powdered coating melts into a glass-like coating.
Glazing is functionally important for earthenware vessels, which would otherwise be unsuitable for holding liquids due to porosity. Glaze is also used on functional and decorative ware made of stoneware and porcelain. In addition to the functional aspect of glazes, aesthetic concerns include a smooth pleasing surface, the degree of gloss and finished color. Glazes may also enhance an underlying inscribed, carved or painted design.
Glazes are most often a mix of dolomite, frit, silica/flint, feldspar, sodium borate, clay and whiting plus metal oxides or carbonates. Although a dry glaze mix can be useful, the chemicals are usually mixed with water, with the addition of a material such as bentonite to keep the mixture in suspension. Glaze recipes are carefully formulated to melt at appropriate temperatures and produced a surface with desired characteristics.
Glaze may be applied by dusting a dry mixture over the clay, or by dipping the piece in the slurry of glaze and water. Liquid glaze can also be applied by splashing or with a brush. Brushing tends not to give an even covering, but can be effective with a second coating of a coloured glaze as a decorative technique.
With all glazed items, a small part of the item (usually on the base of the piece) must be left unglazed, else it will stick to the kiln during firing.
See also
Reference
- Hamer, Frank and Janet. The Potter's Dictionary of Materials and Techniques. A & C Black Publishers, Limited, London, England, Third Edition 1991. ISBN 0-8122-3112-0.nl:Glaceertechniek