This report presents the findings and methodology of a study which demonstrated that the immobilization of appropriate pH-sensitive or amine-reactive compounds onto suitable solid supports can yield fingermark lifters, which enables instantaneous, on-the-spot visualization of marks without leaving behind signs of their application.
Although several compounds and synthetic techniques were investigated to fabricate such lifters, simple adsorption of commercially available indicators onto membranes proved to be the most cost-effective approach. Lifters impregnated with phenol red, pyranine, or fluorescamine, in particular, enabled detection of marks of varying ages and from various substrates. Comparative studies indicated that these lifters can, under ideal conditions, produce results close to those obtained with commercial black gelatin lifters; however, the requirement of a certain degree of residual moisture on their surface represents a significant challenge, which must be overcome before these novel lifters are ready for operational evaluation. Several storage methods were examined for their ability to enable out-of-the-box use of the lifters. Of those, vacuum-sealing appears to be the most straightforward option. Even though this method did not yield consistent results in this study, due to equipment limitations, there is no reason why, with industrial-level materials, it should not be possible to package lifters so that the necessary level of moisture is retained. Also, the incorporation of moisture-retaining hydrogels in the packaging promises to facilitate the application of the lifters by end-users and yield more consistent results. Although at the current stage the lifters do not have any advantages over established detection techniques for routine applications, they have the potential to be used for specialized applications, such as covert operations. 18 figures and 31 references