Small Particle Reagent is comprised of which fine particles?

Small Particle Reagent (SPR) is specifically designed for the enhancement of latent fingerprints on various surfaces, particularly non-porous ones like glass and metal. The primary component of SPR is molybdenum disulphide, which consists of very fine particles that adhere to the lipid components of the fingerprint residues. This adherence allows for a visible enhancement of the latent fingerprints under certain light conditions, making them easier to analyze.

Molybdenum disulphide's unique properties, such as its layered structure and low friction, contribute to its effectiveness in fingerprint visualization. When the fine particles are applied to a surface where a latent print might be present, they bond to the residues left behind, providing contrast against the background, which is essential for any forensic analysis.

In contrast, sodium chloride, carbon black, and iron oxide do not serve the same function or possess the specialized characteristics required for fingerprint enhancement in the way that molybdenum disulphide does.