The colours at Pompeii are still so rich: the perfect red, the perfect blue. And we can clearly see the influence that these Roman wall decorations had nearly two thousand years later in artistic houses such as Charleston. Fresco means ‘fresh’: ground pigments, mixed with lime and water, were painted on to walls still fresh with damp plaster. When more expensive colours were used (such as this blue made from lapis lazuli) the paintings were also coated with tempera made from egg yolk and glue.