Cuerda seca (Spanish for "dry cord") is a technique used when applying coloured glazes to ceramic surfaces. When different coloured glazes are applied to a ceramic surface, the glazes have a tendency to run together during the firing process. In the cuerda seca technique, the water-soluble glazes are separated on the surface by thin lines of a greasy substance to prevent them running out of their delineated areas. A dark pigment such as manganese carbonate is usually mixed with the grease to produce a dark line around each coloured area. * Tile from Khargird in Iran, mid 15th century * * *