Forensic science - fingerprint analysis - Essay Example

Ninhydrin treatment involves dipping the items in a ninhydrin solution and allowing the prints to develop over 24 to 48 hours (Lennard, 2001). Physical developer is an aqueous solution, which contains a ferrous/ferric redox system along with silver nitrate and citric acid, and stabilised by a surfactant. Placing a document in the reagent, leads to the deposition of silver from the solution onto any latent fingermarks. The reaction is catalysed by water-insoluble components of the deposit (Lennard, 2001).

Small particle reagent is a suspension of molybdenum disulfide in a detergent solution. Small particle reagent suspension can be applied with a spray and then rinsed with water to remove the excess powder (Lennard, 2001). Cyanoacrylate treatment is either with cyanoacrylate vapour or cyanoacrylate fuming, which results in the formation of a hard, white polymer on any latent print. The reaction is catalysed by moisture and ionic material present in the deposit. Cyanoacrylate fuming can be done with home-made chambers, expensive commercial units or portable fuming systems (Lennard, 2001).

Basic Yellow 40 (BY40; Maxilon Flavine 10 GFF) is a non-toxic, highly fluorescent dye, which stains cyanoacrylate-developed latent prints. The stain has an excitation maximum at 440 nm with a luminescence emission peak at 490 nm. Basic Yellow 40 is very sensitive to ultraviolet light and can be used with a simple long-wavelength ultraviolet lamp (Security & Safety Supply.) When considering chemical treatments, the surface type is a major consideration. Latent fingermark deposits behave differently on different substrate types; therefore, some techniques are effective on some surfaces, but not on others (Lennard, 2001).

For porous surfaces, the choice of chemical treatment will depend on whether the item was wet or not. If the item has been wet, the method