Development of latent fingerprint by ZnO deposition

Vacuum metal deposition (VMD) utilizing sequential Au and Zn depositions has been an effective technique to develop latent fingerprint on plastic surfaces. A simplified vacuum deposition process was conducted to develop fingerprint in this study. While pure ZnO was thermally evaporated in a vacuum system, ZnO could condense on polyethylene terephthalate (PET) surface. Direct deposition of ZnO, without applying Au seeding, yielded normal development of latent fingerprint. The development of aged fingerprint by ZnO deposition was more effective than that by Au/Zn VMD.