Pottery

In approximately the 6th century BC, Athenians began to create decorative and functional black-and-red-figure pottery. After creating the three dimensional shape, they would apply a liquid form of clay, known as slip, which, once fired, would turn black. The areas that they wanted red would be left alone.

The process required the manipulation of oxygen levels in the kiln, since the clay contained iron, and after being exposed to water and oxygen would turn red. In red-figure pottery, the image would be drawn in negative, meaning that the slip was applied to all of the areas that would be exposed to the oxygen.