Underglazes are not glazes themselves but are colorants applied to unfired bisqueware (greenware) before an overglaze is applied (usually the overglaze is transparent to really let the colors of the underglaze shine through). Underglazes provide the flexibility for a huge range of creativity. Firstly, there’s the range of colors you can use, as you can mix the underglazes to get your perfect shade. With underglazes, you have the opportunity to paint your own detailed designs and patterns. You can even use the underglazes like watercolors, as when you’re painting straight onto a rough clay surface, there’s less chance of the glazes slipping. Clay is impressionable. Textures can readily be added to wet pots through impressing a variety of tools and objects into the surface. Clay is also carve-able. Marks and designs can be incised into leather-hard greenware. By doing so at the leather-hard stage of drying, the cuts retain their crispness. Leather-hard greenware also allows for more ease when incising more intricate patterns. Marbling with two different types of clay—say, a white clay body and a terracotta (or alternatively a colored clay)—is a wonderful way to create different effects on your pottery. One of the best ways to do it is to roll out the two different colors of clay into sheets, then stack them on top of each other. Then start gently rolling the whole block. The colors will mix together and make the most beautiful marbled patterns and from there you can hand build or use a mold to create your desired shape.
