Colouring or coating of a ceramic product, e.g. a tile or slab, by applying a low-viscosity clay mass (slip). The colours are created by the different proportions of minerals and metal oxides, and a fine top layer with a matt surface is created during firing. An engobe can create a matt surface by adding glass-forming materials, but also matt glossy to glossy ones. In contrast to a glaze, the physical properties of the ceramic product, e.g. its abrasion resistance or water absorption, are hardly changed by an engobe. Engobed tiles or slabs are considered unglazed according to DIN EN 14411. There are water-permeable and water-impermeable engobes.
Source: bauwion
