Comparison of commercial and house-made artificial fingermark residue simulants

Latent fingermark residue is a chemically complex and highly variable matrix, presenting challenges when evaluating development techniques. To support furthering research into the chemical composition of fingermarks and mechanistic understanding of development techniques, artificial residue simulants have been proposed as a method of controlling fingermark variability. This study compared two fingermark simulant emulsions: a house-made (HM) formulation and a commercially produced emulsion from Pickering Laboratories to assess their ability to mimic natural fingermark residue. Artificial marks were deposited using a rubber stamp on porous and non-porous substrates, then observed with an optical microscope and developed using indanedione-zinc (IND-Zn), cyanoacrylate (CA), iron-oxide based powder suspensions (FePS), or physical developer (PD). Microscopy revealed physical differences between artificial and natural residues, with neither simulant replicating homogeneous ridge deposition and consistency. The Pickering emulsion exhibited strong development with CA and IND-Zn, while the HM emulsion showed superior reactivity with FePS. Neither simulant was successfully developed with PD. Similarity assessments demonstrated only partial alignment with natural donor mark development and variability between techniques. Overall, although both emulsions contained relevant chemical components and were successfully developed by some techniques, neither simulant fully nor consistently represented natural fingermark residue. These findings further illustrate the complexity of residue-technique interactions and highlight the continued need for further research into artificial simulants to enable mechanistic research on fingermark development processes.