What technique involves hammering a design into a metal with a low relief on the reverse side?

Repoussé is the correct technique that involves hammering a design into metal, creating a low relief on the reverse side. This method allows the artist to manipulate the metal into raised designs or patterns by working from the back of the piece. As the artist hammers the metal, it stretches and takes on form, resulting in an embossed effect on the front side, while the back retains an unadorned surface.

In contrast, chasing refers to the process of creating a design on the surface of metal by pushing or carving directly into it, usually resulting in an incised or more defined pattern without relief. Engraving is a method involving cutting lines into the surface of a hard material using tools, primarily for decorative purposes. Casting involves pouring molten metal into a mold where it solidifies, creating a three-dimensional object, but does not involve the same manipulation of the material to create relief effects. Understanding these distinctions helps clarify why repoussé is specifically characterized by its unique method of forming designs into metal.