Physical Processing Methods
Physical processing refers to solid state and aqueous fingerprint powder development. The particles of fingerprint powders and fingerprint powder suspensions physically adhere to the oils and moisture in latent prints. Fingerprint powders are used to develop prints on clean, dry nonporous surfaces. Powder processing is not as sensitive a processing technique as chemical processing methods; thus, it should only be used on fixed objects at crime scenes or as a final step in a chemical processing sequence. This text examines the use and colors of six types of fingerprint powders: granular, magnetic, fluorescent, metallic, infrared, and nanopowders.