ABSTRACT
Before an item is processed for fingerprints, a fingerprint analyst must examine the substrate. Substrates may be porous, nonporous, or semiporous. Nonporous items are impermeable to gases and liquids. Examples of nonporous substrates include glass, metal, and plastic. Porous substrates are permeable to liquids and gases. The word porous means “containing pores.” Examples of porous substrates include paper, cardboard, and wood. Semiporous substrates are a combination of nonporous and porous. They are less permeable to gases and liquids, although some absorption does occur. Examples of semiporous substrates are photographs, cardboard packaging, and magazines.
