A comparison of enhancement techniques for footwear impressions on dark and patterned fabrics

The use of chemical enhancement techniques on porous substrates, such as fabrics, poses several challenges predominantly due to the occurrence of background staining and diffusion as well as visualisation difficulties. A range of readily available chemical and lighting techniques were utilised to enhance footwear impressions made in blood, soil and urine on dark and patterned fabrics. Footwear impressions were all prepared at a set force using a specifically built footwear rig. In most cases, results demonstrated that fluorescent chemical techniques were required for visualisation as non-fluorescent techniques provided little or no contrast with the background. Occasionally this contrast was improved by oblique lighting. Successful results were obtained for the enhancement of footwear impressions in blood, however the enhancement of footwear impressions in urine and soil on dark and patterned fabrics was much more limited. The results demonstrate that visualisation and fluorescent enhancement on porous substrates such as fabrics is possible.