Sgraffito
Decoration made by scratching through a top layer to reveal a different colour beneath.
Also: scratchwork
Sgraffito is Italian for scratched. On buildings, two layers of plaster in contrasting colours are applied, and a design is cut through the top one while it is still soft. Renaissance house fronts in Italy, Bohemia and Germany were decorated this way, often to look like cut stone blocks. Potters use the same idea, coating a pot in a contrasting liquid clay and scratching a pattern through it before firing. The technique gives sharp two-colour designs that last as long as the surface itself.