Glaze and underglaze are both ceramic materials used for decoration and finishing, but they have distinct characteristics and purposes.
Glaze is a glass-like substance that is applied to the surface of a clay piece and fuses to the clay during firing. Underglaze, on the other hand, is a colored material applied to the clay surface before glazing.
Glaze is typically applied over the entire surface of a piece to create a protective and decorative coating. Underglaze is applied selectively for designs and patterns.
Glaze undergoes a chemical transformation during firing, melting into a glassy surface. Underglaze does not turn into glass but bonds with the clay and remains distinct from the glaze.
Glaze can create various textures, from glossy to matte. Underglaze maintains its texture and can be applied with different techniques, such as brushing, sponging, or stamping.
Glaze provides a waterproof and food-safe surface, making it suitable for functional pottery. Underglaze is not usually used as the primary food-safe surface and is often covered with a clear glaze.
Understanding the differences between glaze and underglaze helps ceramic artists make informed choices when decorating and finishing their clay creations.