In-glaze or inglaze is a method of decorating
pottery
Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and p ...
, where the materials used allow painted decoration to be applied on the surface of the
glaze before the
glost firing
Ceramic glaze is an impervious layer or coating of a vitreous substance which has been fused to a pottery body through firing. Glaze can serve to color, decorate or waterproof an item. Glazing renders earthenware vessels suitable for holding ...
so that it fuses into the glaze in the course of firing.
It contrasts with the other main methods of adding painted colours to pottery. These are
underglaze
Underglaze is a method of decorating pottery in which painted decoration is applied to the surface before it is covered with a transparent ceramic glaze and fired in a kiln. Because the glaze subsequently covers it, such decoration is completely ...
painting, where the paint is applied before the glaze, which then seals it, and
overglaze decoration
Overglaze decoration, overglaze enamelling or on-glaze decoration is a method of decorating pottery, most often porcelain, where the coloured decoration is applied on top of the already fired and glazed surface, and then fixed in a second firing ...
where the painting is done in enamels after the glazed vessel has been fired, before a second lighter firing to fuse it to the glaze. There is also the use of coloured glazes, which often carry painted designs.
As with underglaze, in-glaze requires pigments that can withstand the high temperatures of the main firing without discolouring. Historically this was a small group. Inglaze works well with
tin-glazed
Tin-glazing is the process of giving tin-glazed pottery items a ceramic glaze that is white, glossy and opaque, which is normally applied to red or buff earthenware. Tin-glaze is plain lead glaze with a small amount of tin oxide added.Caiger-Smith, ...
pottery, as unlike
lead glaze
Lead-glazed earthenware is one of the traditional types of earthenware with a ceramic glaze, which coats the ceramic biscuit body and renders it impervious to liquids, as terracotta itself is not. Plain lead glaze is shiny and transparent after f ...
the glaze does not become runny in the course of firing.
Faience
The very wide range of types of European
tin-glazed earthenware
Tin-glazed pottery is earthenware covered in lead glaze with added tin oxide which is white, shiny and opaque (see tin-glazing for the chemistry); usually this provides a background for brightly painted decoration. It has been important in Is ...
or "faience" all began using in-glaze or underglaze painting, with overglaze enamels only developing in the 18th century. In French faience, the in-glaze technique is known as ''grand feu'' ("big fire") and the one using enamels as ''petit feu'' ("little fire").
[Lane, 1] Most styles in this group, such as
Delftware
Delftware or Delft pottery, also known as Delft Blue ( nl, Delfts blauw) or as delf,
is a general term now used for Dutch tin-glazed earthenware, a form of faience. Most of it is blue and white pottery, and the city of Delft in the Netherlands ...
, mostly used
blue and white pottery
"Blue and white pottery" () covers a wide range of white pottery and porcelain decorated under the glaze with a blue pigment, generally cobalt oxide. The decoration is commonly applied by hand, originally by brush painting, but nowadays by stenc ...
decoration, but Italian
maiolica
Maiolica is tin-glazed pottery decorated in colours on a white background. Italian maiolica dating from the Renaissance period is the most renowned. When depicting historical and mythical scenes, these works were known as ''istoriato'' wares ( ...
was fully polychrome, using the range of in- and underglaze colours available.
References
References
*Lane, Arthur, ''French Faïence'', 1948, Faber & Faber
*Savage, George, and Newman, Harold, ''An Illustrated Dictionary of Ceramics'', 1985, Thames & Hudson,
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Ceramic glazes
Types of pottery decoration