Paper and Processing: A Look into Five Processing Types on Common Paper Types

This study was carried out in order to evaluate multiple processing methods alongside each other to determine if, and which, one developed prints more successfully across various paper types. The variety of paper types was of interest because if a contender was identified, an examiner can have a quick frame of reference for which processing method is most likely to develop more information. The paper types investigated in this study were chosen to try to encompass the various types of evidence and examiner can come across during any given case but are not meant to be considered all inclusive. There were 30 participants in this study, all of adult (18+) age. The samples obtained were “charged” meaning the participants loaded their fingertips with oils from their face and hair before depositing. The fingerprint samples were also considered “fresh” because there was an overnight drying period before development. Both the nature of the residue deposited and the time before development categorize the results of this study as ‘ideal’. The closest to a universal processing method for the paper types explored was oil red o. Of the 12 paper types in the study, oil red o had problems with only three. The first were stamps, which were problematic with all other processing methods as well. The other two problematic paper types saw problems with contrast, not development, meaning that a print was developed but an examiner might not be able to distinguish it from the background. The remaining processing methods had varying degrees of success in their development of the latent fingerprints. The chemical properties in the papers themselves were explored in order to find possible explanations for the variation in development.