ABSTRACT
Because latent fingerprints are invisible, they must be processed, or developed, to make them visible. Once they are visualized, they are documented and analyzed. There are four
major limitations that affect the quality of prints recovered from the crime scene or items of evidence:
• Condition of the substrate (texture and permeability) • Environmental effects (dry, humid, rain, wind, etc.) • Quantity of latent print material deposited • Method(s) of development, documentation, and collection
Recall that latent fingerprint deposits are composed of 98% water, lipids (fatty acids, cholesterol, squalene, and triglycerides), amino acids and proteins, environmental contaminants (lotions, soaps, cosmetics, etc.), and the products of environmental chemical reactions following deposition.1-4 The majority of these components are metabolic excretory products from the pores of eccrine glands, which are the sweat glands most abundant along friction ridge structures. Champod et al. state, “Secretions from eccrine and apocrine glands are mixtures of inorganic salts and water-soluble organic components that result in a watersoluble deposit (WSD). Secretions from sebaceous glands consist of a semisolid mixture of fats, waxes and long-chain alcohols that result in a non-water-soluble deposit (NWSD).”5 Sebaceous glands, associated with hair follicles, are most abundant on areas of the skin that perspire, especially the scalp and face.1,4 When one touches the face or scalp, the oils from these areas are transferred to the friction ridges of the fingers and palms.4
