Three fingermark donors were used in this study, including one weak, one medium, and one strong donor. The donors comprised one male and two female volunteers, two of which were aged 20-24 years, one of which was aged 35-40 years. Donors were screened to have not handled food or chemicals, worn gloves, or washed their hands in the preceding hour prior to depositing their fingermarks. Unless otherwise specified, fingermarks were placed in a natural condition, meaning that no grooming to increase the amount of sebum on the fingerpads was performed. The donors were instructed to sequentially apply their fingerpads to separate areas of the dictated surface type with light pressure.