摘要： Forensic practitioners are recommended to dark adapt their eyes prior to conducting evidential searches in the dark. The dark adaptation process remains poorly standardised across the discipline, with little quanti?ed regarding the bene?ts of such preparative steps. Herein, we report the ?ndings of a study that recruited 50 participants to assess the e?ectiveness of the Crime-lite Eye?, a darkness adaptation device developed to assist forensic practitioners both in the laboratory and in ?eld. Participants were tasked with searching for the ?uorescent signatures left by reaction of 1,8-diaza?uoren-9-one (DFO) with amino acids, in a manner akin to the ?uorogenic ?ngerprint treatment of porous evidence. Using an Epson Stylus Photo R265 inkjet printer, ink cartridges were ?lled with alanine solutions of various concentrations, allowing di?erent motifs to be printed onto copy paper and subsequently developed using DFO. Participants searched for this ‘evidence’ both with and without dark adapted vision. On average, participants were able to locate and correctly recognise 16% more evidence once dark adapted using the Crime-lite Eye?. The increase in evidence located by participants once dark adapted suggests that crime scene o?cers should be dark adapting in order to visualise as much as possible. The time taken to dark adapt, 10 min on average during this study, is not excessively long, and should not signi?cantly slow the investigation.