There are up to three components that make up a decorated ceramic tile: the tile body, the glaze, and the pigment, or stain painted onto the glaze by the tile artist.
The material a tile is made of - the tile body – can be one of the following:
Terra cotta is a hard baked clay of reddish, yellow or orange color that is porous and requires sealing unless it is fully covered with glaze. Terra cotta tiles come in various sizes up to 13”x13” and make wonderful floor tiles, just sealed with an acrylic sealer or decorated by an artist. They can also be applied as wall tiles, usually glazed and painted. The painting style is usually of a more rustic character, to properly complement the tile itself. (see picture left)
Kaolin is a hard baked white clay which is the base for most wall tiles. Since it provides a creamy white background it is the tile of choice for under glaze painting, in other words the tile of choice for most hand painted tile. (see picture left)
The glaze is the impervious glasslike finish fused to the tile surface by heating, or firing, the tile in a special oven called a kiln, to a temperature of between 1840’F to 2230’F. It can be applied with a soft brush, a spray gun, or it can be poured on. – Glazes come in a wide range of colors and can have a glossy, satin or matte finish. Colored glazes can also be used to create patterns on tiles or even as a paint medium.
Tile Pigment or Stain
Pigments or stains used for ceramic decoration are all based on metal oxides and carbonates that can withstand the temperatures of the glaze firing. The painting can be under glaze, that is, right on the tile body and covered with a transparent glaze. This method works well for very detailed designs. The painting can also be on glaze, usually a white or ivory colored glaze. The painting is done on the unfired glaze and the pigments melt with and into the glaze during the firing. This method has been used throughout the centuries since it works with all tile bodies no matter whether they are reddish or white and is generally known as the majolica technique, named after the region in Spain where it originated.