AFTE Store - GSR Screen Printing: Nitrite Pattern Replication

In the training of a new firearms examiner and the proficiency testing of a seasoned examiner, it is important to limit as many of the variables as possible. A large variable in the examination of gunshot residues (GSR) is the GSR pattern itself. While the interpretation of GSR patterns is reliable, there are slight variations which occur when examining multiple
patterns fired at the same distance. For this paper, a simple screen printing method was used to replicate a consistent pattern of nitrites on pieces of cloth. The examiner’s technique in performing the chemical test for the presence of partially burned gunpowder particles can be controlled and compared to a known, uniform printed pattern. Additionally, the results could
then be quantified as the evaluator has a known number of spot reactions that should be represented.