A simulated crime scene footwear impression database for teaching and research purposes

Community-shared open-source forensic footwear databases are relatively rare, although it is generally agreed that access to such resources can support a multitude of research and teaching/training goals. The objective of this technical report is to detail the creation of such a dataset that includes both high-quality exemplars and simulated crime scene impressions. To achieve this goal, a variety of shoe makes, models, sizes, substrates, matrices, lifting methods, and enhancement (chemical/digital) techniques were employed and are fully described. The result is an open-source dataset available for download, and comprised of 214 high-quality impressions (87 right outsoles × 2 replicates + 40 left (close non-mated) outsoles), 138 dust impressions (46 outsoles × 3 replicates), and 73 blood impressions (24 outsoles × 3 replicates = 72 + 1 additional replicate). Of the 138 dust impressions, 117 are provided in a digitally enhanced form (via Adobe^® Photoshop and/or Photoshop Camera Raw software), and 120 are provided in an unenhanced form for a total of 237 images. For the blood impressions, all 73 are provided in both unenhanced and chemically enhanced forms for a total of 146 images. Thus, in addition to the outsole scans, a total of 597 simulated crime scene and/or known test impressions are included and fully documented.