NEW YORK – Earthenware has a long history dating back nearly 30,000 years. The ability to form earth and clay into storage, drinking, cooking and household utensils proved helpful, especially as a nomadic life transitioned into more stable communities.
Earthenware by its nature is porous. Forming earth and clay into a pot or utensil, then allowing it to dry has limited use. It is fragile, unable to hold liquid and cannot be made too large as it is bulky, heavy and easily damaged. Firing it at temperatures as high as 1,100 degrees C (2,000 F) is the only way to strengthen it for daily use as a storage container.
However, to make it impermeable for the storage of liquids, a thin, clear coat of lead glaze and other oxides was fired to seal the pot. Later a tin oxide was added to form a white glaze from which a hand-painted decorative element could be applied.
Lead glaze vs. tin glaze
To fire correctly, the basic composition of clay used for earthenware today is 25% kaolin (a silicate), 25% ball clay, 35% quartz and 15% feldspar. When formed together and fired the result is a biscuit, or bisque, from which the final product is glazed and decorated.
A lead-based vitreous compound consisting of powdered glass melts over the earthenware at very high temperatures to create a glossy, transparent, impermeable coating. This type of “enameling” has been found in China as early as the 13th century B.C. Lead glaze is more durable than the tin-glazed compound and is used for molded decorative items that are painted after firing. Lead glaze alone was largely replaced by tin glaze about the 15th century.
Tin oxide was added to the lead glaze about the eighth century in region that is now Iraq to create a white opaque compound allowing colorful overglazes and design to be painted directly onto a mostly flat surface before being fired. This process required more skill since mistakes couldn’t be corrected and therefore was more expensive to produce. Tin oxide became difficult to get during World War I and zirconium and zircon has since been substituted as a cheaper alternative, except in very small quantities.
Identifying tin-glazed earthenware
Once tin oxide was added to lead glaze, most collectible earthenware is made with this formulation.
This is the French name for tin-glazed pottery first produced during the 15th century Renaissance period in the Italian city of Faenza, near Ravenna. Today, it is more of a catch phrase for white tin-glazed pottery glaze that doesn’t have its own particular style. Usually the term refers only to the tin-glazed wares made in France, Germany and Scandinavia.
Said to have come from the Spanish island of Majorca to Italy in the 15th century, this style of tin-glazed pottery is highly decorated with vibrant stylized natural or historical events known as istoriato. It is common in collector circles to identify lead-glaze pottery as majolica and tin-glaze pottery as maiolica.
A vibrant blue and white tin-glazed pottery from the city of Delft in the Netherlands. This style is easily recognized in the Delft blue tiles and jars showing Dutch scenes such as windmills. The heyday of Delftware is from 1640 to 1740 but became popular in England (known as English Delftware), Japan and China in the 18th century. Delftware production continued at a greatly reduced level through Victorian times into the 20th century.
Tin-glaze pottery having a golden iridescent sheen is aptly named luster, or lusterware. Originating in the Middle East in the ninth century, this metallic glaze of copper and other metallic oxides provides an earthy brown to the white tin-glaze underglaze. Luster decoration became popular with English potteries in the first quarter of the 19th century.
Produced during the period of Muslim Spain beginning in the eighth century, tin-glaze earthenware was originally produced using Islamic and Christian elements, particularly the “IHS” monogram and personal coats-of-arms for export to Europe. The 14th and 15th centuries constituted the peak period before the Italian maiolica earthenware become prominent.
From 1520 to 1550, a specialized and highly detailed bas relief white lead glaze earthenware was produced in the French city of Saint-Porchaire intended only for high-end collectors of the time. Known as Henri II ware or Saint-Porchaire Ware, only about 70 pieces survive from the period.
French potter Bernard Palissy (1510-1590) created high relief, polychrome lead-glaze natural scenes such as fish, snakes, frogs and even mussels often from taking casts of the real thing. Known also as “rustic ware,” most examples at auction are 19th and 20th century reproductions attributed to the style of Palissy while the 16th century originals are considered museum pieces.
Making use of the white, glassy lead-glaze coating, potters in 18th century England, particularly from Staffordshire and Leeds, created a relatively inexpensive substitute for porcelain. Josiah Wedgwood’s production of what was called pearlware was so prolific by 1780, that his mass- produced transferware was exported throughout Europe and undercut the more expensively produced tin-glazed, hand-painted earthenware.
When reviewing auction values for vintage lead-glaze or tin-glaze earthenware, it doesn’t seem as if there is a significant difference in the final hammer prices. The style, period, age and condition dictate what is more collectible.
Tin-glazed earthenware doesn’t hold up as well as lead glaze, however. Edges, posts and the feet of tin-glazed objects are prone to crack and decay more often than the harder edge lead-glaze pottery.
While most early tin-glaze and lead-glaze pottery have higher auction values, a resurgence in replicating early Renaissance tin-glaze pottery in Italy in the early 20th century can be an alternative. Artists such as Roger Fry, Duncan Grant, Alan Caiger-Smith and others from the 1920s to the 1950s can be the start of an alternative collection. Even Picasso has his own brand of tin-glaze earthenware design.
There is a lot more to glazed earthenware to discover. With so many design elements and periods to choose from, tin-glaze and lead-glaze earthenware easily lends itself to the collector mantra: Collect what you like first.