My clay tiles appear to have an applied 'painted' finish. Why? & will this weather off?

The beauty of clay tiles lies in the way in which they retain the natural colour of the clay material, whilst maturing to a deeper, richer shade.

Colours can be created by applying an ‘Engobe’ to the surface of the tile prior to firing in the kiln. This is a ceramic material, as is the tile itself. Therefore when the tile is fired the engobe and the tile ‘fuse’ together and become one. This means that the surface colours of the tiles are permanent will not fade under any circumstances and any slow change that does take place will be due to mosses, lichens or pollutants attaching to the tile surface.