The work involves two highly skilled techniques, repoussé, meaning pushed out from behind, because the metal is worked using a hammer and shaping tools from the reverse side, and chasing. The metal may be worked on an adjustable anvil or over a bed of pitch that supports the material as it is shaped. These techniques allow the achievement of tremendous detail, not only with regard to facial and other features, but also in the remarkable flow of garments and the rich decoration of ornamental haloes.