Retouch (lithics)

Retouch is the act of producing scars on a stone flake after the ventral surface has been created. It can be done to the edge of an implement in order to make it into a functional tool, or to reshape a used tool. Retouch can be a strategy to reuse an existing lithic artifact and enable people to transform one tool into another tool. Depending on the form of classification that one uses, it may be argued that retouch can also be conducted on a core-tool, if such a category exists, such as a hand-axe.

Retouch may simply consist of roughly trimming an edge by striking with a hammerstone, or on smaller, finer flake or blade tools it is sometimes carried out by pressure flaking. Other forms of retouch may include burination, which is retouch that is conducted in a parallel orientation to the flake margin. Retouch is often taken as one of the most obvious features distinguishing a tool from a waste by-product of lithic manufacture (debitage).

The extent of reduction, also known as the retouch intensity, is denoted by a measure of the reduction index. There are many quantitative and qualitative methods used to measure this.