Athenian Vase Painting and the Three Firings

All Athenian pottery starts as the same reddish clay. Painters decorated it with a liquid clay slip, then fired it through three atmospheric stages. First, oxidizing: the kiln is open to air, oxygen turns the iron in the clay to a red iron oxide, and the whole pot glows orange. Second, reducing: the kiln is sealed and damp wood is added, choking off oxygen. Carbon monoxide pulls oxygen out of the iron, and both clay and slip turn black. Because the slip is finer and more tightly vitrified than the coarser body clay, it comes out glassy. Third, reoxidizing: air is let back in. The porous body clay reabsorbs oxygen and turns orange again, but the sealed, glass-like slip cannot, so it stays black.

This single process produces two opposite painting styles. In black-figure, painters paint the figures in slip, so the figures fire black and the background stays orange; details are scratched into the black slip with a sharp tool, an incised line that is uniform and scratchy. In red-figure, painters reverse the technique: they paint the background in slip and leave the figures as bare clay, so the figures stay orange against a black ground. Freed from incising, painters now draw details with a brush, a relief line that can swell, taper, and curve, giving far more flexibility for anatomy, drapery, and foreshortening.

That new flexibility shows up directly in composition. The Niobides Krater, painted in Athens around 450 BCE, scatters its figures at different heights across the surface instead of lining them up on one groundline, suggesting a landscape with rolling ground. This looser, more spatial arrangement follows naturally from a technique that could finally draw a figure instead of just scratching its outline.