A Literature on Development of Latent Fingerprint by Small Particle Reagent

Abstract

The small particle reagent is essentially a suspension of an insoluble powder in solution of a surfactant by which latent fingerprint on wet surfaces can be developed. SPR is sensitive towards the lipid constituents in the latent fingerprint residues. Adherence of fine particles suspended in a treating solution to the fatty or oily constituents of latent fingerprint residues accordingly may be regarded as a same as methods as powder dusting method. Small particle reagents consisting of suspension of fine particle (Molybdenum disulfide) in detergent the particle adhere to the fatty constituents of latent fingerprint residues. Conventional SPR contains dark grey coloured Molybdenum disulfide particles, suspended in detergent which gives effective result on non-porous surfaces. use of graphite, cobalt oxide, lead oxide, Xerox powder and monastrol blue dye has also been used. The powder suspension is commonly referred to as small-particle reagent (SPR), and the technique is essentially a wet powdering method. The powder suspension is sensitive to the sebaceous (water insoluble) components of the latent fingerprint and can be used on a wide range of non-absorbent surfaces.