A black line which is painted so as to stand in relief on the surface of a vase to catch reflected light and sharply define details and figures. Invented for black figure, for spears, etc., but especially used in early red figure. It is not clear how it was applied - with a very fine brush and using a careful clay preparation, or even laid on with a hair.
Above: Detail from Fragment of black-figure clay vase from Acropolis in Athens. Photo. Claudia Wagner. © Claudia Wagner.