An engobe is a coloured or white slip, adjusted with materials such as feldspar and silica, that is applied to clay to change its surface colour or texture. It sits between a plain slip and a glaze.
What Is Engobe?
Plain slip is just liquid clay, and if it shrinks differently from the clay it is painted onto, it can flake off. Engobes are formulated to shrink less and bond better, so they can be applied to leather-hard, bone-dry or sometimes bisqued clay without peeling.
Potters use engobes to cover a dark clay with a white or coloured surface, to create a background for brushwork or sgraffito, or to add a satin, stony layer under a clear glaze. They can be brushed, dipped, poured or trailed, and coloured with stains or oxides.
Commercial underglazes are close relatives and are often described as engobes. Whatever you call it, test the combination of engobe, clay and glaze on a tile first, because a poor fit shows up as flaking, crawling or glaze that pulls away from the engobe in the firing. Keep notes of the clay and the stage you applied it at.
This pottery glossary entry from Le Studio Art Space is general educational content. Always follow the clay, glaze and kiln makers’ data for your own materials and equipment.