Every first-time potter has the same moment: you choose a dusty grey liquid and are promised it will come out of the kiln a glossy cobalt blue. It sounds unlikely. It works.
What glaze actually is
Glaze is a thin coating of glass-forming minerals. In the kiln it melts, fuses to the clay and develops its final colour.
Choosing well
Look at our test tiles rather than the bucket, think about how the piece will be used, and remember that glaze pools in grooves and breaks thinner over edges.