The greatest of the whites, and certainly the cruellest, is made of lead. It is hard to imagine a history of art without this dense ‘silver’ white.
Lead may have been liberated from its ores as early as 5000 years ago as there is extensive evidence of lead smelting in Anatolia from around 2300 BC.
The manufacture of white lead from the metal is remarkable partly for its methodical process and partly for its longevity: much the same technique was used in Ancient Rome and most probably employed centuries earlier in Egypt, was still in use in the 19th century.
In use for at least the last 50,000 years it is one of the first pigments used by mankind. Readily available and easy to grind into a powder it had no challenger until the invention of the lead whites in Ancient Greece.
Composed of the fossilised microscopic remains of phytoplankton algae, chalks often develop as very thick and extensive deposits, the most famous being the cliffs of the English southern coast.
How can this bright white come from a black mineral?
The dark-coloured mineral ilmenite is rich in iron and titanium and this potential pigment was identified as an element in 1795. Naturally occurring titanium dioxide was not used as a pigment because it was too highly contaminated with iron and a suitable purification method was not developed until the 1920’s.
Bianco San Giovessi
By the end of the 18th century the risks associated with lead white were a matter of serious concern and an alternative white was demanded.
The white oxide of zinc was well known to the Greeks who observed that zinc oxide forms a white vapour that condenses in fluffy deposits. It was known in the Middle Ages as the ‘philosopher’s wool’ and as ‘ flowers of zinc’.
Metallic zinc had originally come from China and the East Indies. When zinc ore was found in Europe, large- scale production of the extracted metal began.