ABSTRACT
Latent and patent prints are occasionally composed of substances handled during the course of the day rather than eccrine sweat. Contact with automobile grease, cooking oil, makeup, or lotion results in oily or greasy latent or patent prints. These prints are processed with Sudan black, natural yellow 3, or with vacuum metal deposition (VMD). Latent or patent prints in blood are observed at crime scenes, whether a violent crime has occurred or not. Burglars often break a window to gain entrance to a residence, cutting themselves in the process. Blood prints are processed with amido black, acid yellow 7, or amino acid reagents (indanedione, DFO, and ninhydrin). Latent prints are also commonly found on adhesive substrates such as tapes and labels. The adhesive substrate is processed with powder suspension or crystal violet. In this laboratory exercise, prints in blood, oils, and on adhesive substrates are processed with chemical reagents and powder suspensions.
