A foundational coating of slip applied to leather-hard or bisque-fired clay. It is used to mask the color of the underlying clay body, smooth out a rough texture, or provide a contrasting background for sgraffito, painting, or colored glazes. Underslips must be formulated to match the shrinkage rate of the clay body to prevent flaking.
Heard on the job
Apply a white underslip to the red earthenware before you start painting the cobalt patterns.