Ceramic; Tin-glazed earthenware bowl painted with an inscription painted in cobalt blue pigment under the glaze, and with ruby lustre applied over it, most of which has worn off through burial. Inscribed in Arabic, 'one of what was made […]'. Iraq, probably Basra, 850-900.
Tin-glazed earthenware bowl painted with an inscription painted in cobalt blue pigment under the glaze, and with ruby lustre applied over it, most of which has worn off through burial. Inscribed in Arabic, 'one of what was made […]'.
This bowl is made from earthenware, but the pinkish ceramic body has been disguised by the use of an opaque tin glaze, which is made by adding particles of tin oxide to the glaze recipe. The use of tin opacification in glazes was first invented in Iraq in the early 9th century, where it was used to imitate the bright whiteness of imported Chinese porcelains. Tin-glazing was used throughout the Middle East until the middle of the 11th century, when a new, artificial ceramic body, known as fritware, was invented by potters in Egypt.
An Arabic inscription in cobalt blue pigment was written on to the tin-glaze after it was applied and had dried, which then fused into the glaze during the first firing. The inscription reads, 'one of what was made […]', which was quite a common inscription on bowls produced at this time, although very few of them mention the name of a craftsman or patron.
The bowl was next decorated in lustre, an overglaze technique using metallic pigments derived from silver and copper, which was also invented in Iraq in the early 9th century. The lustre pigments were painted on the hard shiny surface of the pot after it had been glazed, and it was then refired in a reducing kiln (an atmosphere starved of oxygen). Lustre became a very popular technique for decorating Islamic ceramics, and was especially used to imitate the designs of metal objects.
The type of lustre used here is known as 'ruby lustre' since it was very rich in copper and fired to a deep red colour. Unfortunately, most of the ruby lustre has worn off this bowl, probably due to the fact that it was buried for hundreds of years. Objects decorated in ruby lustre are very rare, and it does not seem to have been used by potters for very long, before being abandoned in favour of using a single colour derived from silver.