Morgan-Smith R.K., Elliott D.A., and Adam H. Enhancement of Aged Shoeprints in Blood. J. Forensic Ident. 2009; 59 (1): 45-50.
A general conclusion of the testing is that it is worth attempting to enhance shoeprints in blood even if the substrates have been exposed to the weather for approximately 1 week. Regarding the performance of the various reagents tested, ninhydrin performed best on porous substrates such as paper products. Even on impressions exposed to rain, ninhydrin was successful in revealing additional damage features after the other reagents had failed. Amido black performed best on nonporous substrates such as linoleum or wooden flooring after 16 weeks of exposure. Three distinctly different shoe-sole pattern styles were used to create the test impressions. Each shoe sole had damage features added to the toe, ball, and heel to provide specific features that would aid in the assessment of the enhancement. Impressions were made from the shoe soles and split into three parts (toe, ball, and heel) in order to allow one part to be used with each reagent. Care was taken to ensure that the impressions were as similar in intensity and clarity as possible. Six reagents were initially tested: two amino acid staining techniques (ninhydrin and diazofluorenone); two protein staining techniques (amido black and coomassie blue); and two peroxide staining techniques (leucocrystal violet and fluorescein). Each set of prints was placed in three types of environments: on the shelves in a dimly lit interior room, outdoors in a sheltered area and outdoors in an area exposed to the weather. The totally exposed environment was rained on for 3 days during the first week. This report describes the testing period and the evaluation method.