Instead of coating the entire vessel with slip, it could just be added to certain sections by applying it with a wide brush. Using a colour that differed from that of the clay body or the underlying coat of slip produced more decorative variation and a greater contrast to the other elements like slip-trailed patterns. This meant that some parts of the vessel had two coats of slip (see also slip (coat of slip) or double-slipping).

Translation Sandy Haemmerle

German: Zonale Grundengobe

French: Engobe de fond partiel

References:

Heege 2016
Andreas Heege, Die Ausgrabungen auf dem Kirchhügel von Bendern, Gemeinde Gamprin, Fürstentum Liechtenstein. Bd. 2: Geschirrkeramik 12. bis 20. Jahrhundert, Vaduz 2016, 84-85.