Cuerda seca (which means in Spanish "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
outside of their delineated areas.
Such dividing lines are produced by a darker
pigment such as manganese carbonate, usually
mixed with the grease to produce a dark line
around each coloured area.