Painting technique

Glaze is a term for painting with a transparent medium. In other words, whatever is on the surface beneath the glaze will still be apparent after the glaze has been applied. The glaze will merely change the color cast of the surface. This is a technique that has been used for centuries in fine art. When the technique is used for wall glazing, the entire surface is generally covered, often showing traces of texture (French Brush, Parchment, Striae, Rag Rolling). Either oil-based or water-based materials may be 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 uses the same technique as glaze except that opaque paint is used instead.

Cooking technique

Glaze is also a term in cooking to mean a coating of a glossy mixture applied to food. Egg whites and icing are both used as glazes.

Pottery Glazes

In pottery, glazing is the process of coating the piece with a thin layer of a glassy material. Glazes are 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. Glazing is important for functional 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.

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.

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.