Repoussé is a metalworking technique in which a malleable metal is ornamented or shaped by hammering from the reverse side to create a design in low relief.
While repoussé is used to work on the reverse of the metal to form a raised design on the front, chasing is used to refine the design on the front of the work by sinking the metal. The term chasing is derived from the noun "chase", which refers to a groove, furrow, channel, or indentation. The adjectival form is "chased work".
The techniques of repoussé and chasing use the plasticity of metal, forming shapes by degrees. There is no loss of metal in the process as it is stretched locally and the surface remains continuous. The process is relatively slow but a maximum of form is achieved, with one continuous surface of sheet metal of essentially the same thickness. Direct contact of the tools used is usually visible in the result, a condition not always apparent in other techniques, where all evidence of the working method is eliminated.
The techniques of repoussé date from Antiquity and have been used widely with gold and silver for fine detailed work and with copper, tin, and bronze for larger sculptures. Classical pieces using this technique include the bronze Greek armor plates from the 3rd century BC.