Underglaze is applied to raw or bisque ware. Underglaze fuses to the clay body during firing. Paper clay should be bisque fired to a minimum of 1080℃. prior to application of underglaze. Apply by brushing, sponging or air brush. Underglaze is suitable from 1000-1280℃. Most colours are suitable for temperatures up to 1280℃ however these should be tested for your firing conditions.