A silver foot

A metal cast of a footprint, such as those often made of a new baby’s feet, is perhaps the most intuitive example of a three-dimensional index. It is the mould though, not the cast, that is the true (or at least the frst true) index here. But when a cast is taken from this mould to produce the ‘positive copy’ the same process is surely taking place again? In making a cast foot there is a creation of two indices (the mould, the cast) as well as the creation of a double index (the cast made via two successive indexical processes).