Evaluation of an Innovative Casting Method in the Recovery of Footwear Impressions in Soil

Abstract

Three-dimensional (3D) shoeprints taken from crime scenes can more accurately depict impressions than photographs, providing a crucial link between the crime scene and the suspect. This paper introduces rigid polyurethane foam as an alternative material for recovering and preserving 3D footwear impressions in soil. The rigid polyurethane is manufactured through gas expansion, solidifying in a foamed state that consists of a dense integral surface and a durable closed-cell structure beneath the skin layer. It is easily molded, lightweight, dimensionally accurate, and exhibits minimal changes in strength when the foam casts are created and stored indoors. In comparison to casts made with plaster of Paris, this method produces impressions on casts that exhibit more identifiable characteristics, serving as a complementary technique for the forensic science community in reproducing 3D footwear impressions found in soil.