Shopping cart contents0  products - Total 0.00 €

Ceramics terminology

Classical Chinese, light grayish green, high temperature glaze. The item gets its green shade during the firing process (gas or wood burning kiln), when the clay or glazing contains iron oxide.

Colored or white clay slip, which is applied on the item before firing when the clay is medium-dry. Engobes can be used in brush or sgraffito techniques. Famous Iris ceramics commonly contains engobe decorations.

Porous, pale body, which is fired in medium temperature approximately 1050-1150°C. Famous faience items include Mediterranean blue and white decorated majolica ceramics.

Occasionally during the wood or gas firing process the flames can cause piquant, arbitrary and asymmetric spots on the item's glazing, these are called flambé effects (flame or ash effects).

Sang de boeuf
Copper glazing is usually either green or turquoise depending on the composition of the glazing, but gas and wood firing processes produce a blood red effect. Some Arabia's artists like Toini Muona and Friedl Kjellberg are famous for their classical Chinese type Sang de boeuf art.

Durable, high temperature and waterproof ceramic. Stoneware is usually fired in 1200-1300°C so that the clay sinters.

High-temperature clays
High-temperature clays are usually pale and they tolerate high temperatures, sometimes even 1400°C. Finnish natural clay is low-temperature quality and very ferrous.

Shiny or matter glassy coating on an item. Glaze usually contains quartz, feldspar and other minerals. The glaze gets its color when different color metal oxides are mixed with the glaze.

In traditional maiolica technique decorations are brush painted on tinny, white, unfired glaze with color metal oxides.

Low-temperature clays
Low-temperature clays like Finnish red clay are fired in lower temperatures like 700-1000°C so that the clay stays porous.

Paper clay
Paper clay is made by mixing clay with paper fiber (cellulose), which burns out during the firing process. You can make large items of paper clay and they are durable fired and unfired. Paper clay items weight significantly less than regular ceramic items. Paper clay is probably the most versatile of recently developed clay types.

Reduction firing
Flame kilns have the option to reduce the combustion air by closing the flue dampers, which generates smoky reduction firing atmosphere. This changes the shades of the clay and glazing. This technique is used to produce celado and Sang de boeuf glazes.

White, sintered and translucent clay material, which is fired in 1300-1400°C. Traditional porcelain contains 50 % of kaolin clay, 25 % of feldspar and 25 % quartz.

Red clay
Finnish, low-temperature and ferrous clay is grey in the wild, but during the firing process the color changes to terracotta red. Usually Finnish red clay melts if the temperature is over 1050°C.

Bisque firing
Bisque firing is the first firing and during this process clay cooks and transforms to ceramic. After this phase the item is glazed and fired the second time in so called glaze firing.

Traditional firing method used in Far East, which has spread to West in recent years. Rough chamotte rich body is used, which tolerates temperature variations. Raku items are taken from the kiln when they are fiery (approximately 1000°C) using long tongs and then they are placed in a smoker. During smoking the items develop a beautiful lustrous finishing.

Ceramic material, which has been fired in high temperature and crushed before using. Chamotte is added to clay to enhance the quality. It helps for example reducing the risk of shrinking and bursting.

Smoking, black smoking
In smoking (for example by sawdust or straws or in a pit) process bisque fired and polished items obtain dramatic black and grey shades.

Scratching top glaze or engobe layer in order to bring out the lower different color surfaces. Sgraffito technique enables clear non-runny colors and thin lineal ornaments.

In sintered item the body is fired in very high temperature and clay particles have melted against each other. The item loses porosity and becomes waterproof.  

Salt glazing
Salt glazing can be done only in wood or gas kiln. During the firing process sea salt (or something similar) is thrown into the furnace. When the salt is steamed sodium fuses with clay's silica and forms a thin glaze coating on the item. The glaze is very durable and it reminds of orange peel. Salt glazing is traditionally used in pharmacy ceramics and liquor bottles.