Two fluid brands were tested, Liquid Window and Mail Stripper. Three pieces of paper stock were divided in half, and a hand was placed on two of the pieces for about 1 minute. Each piece of paper with a print was then sprayed half with Liquid Window and half with Mail Stripper. One piece with prints was untreated, and a third piece without prints was treated. After approximately 10 minutes, the papers were examined. The Liquid Window evaporated without a trace, while the mail Stripper left an oily residue which evaporated without a trace after a longer period of 30 minutes. After evaporation, examination with light of the visible, ultraviolet, and infrared spectra, as well as with argon-ion laser-generated light, failed to provide any evidence of treatment with either product. The first two pieces of paper were then treated with a standard ninhydrin solution, and fingerprint images of equally good quality were produced. About 100 fingerprints on several types of paper stock were subsequently developed after treatment with visualization fluid and compared to nontreated control fingerprints. Fingerprints exposed to visualization fluid developed slightly less dark than unexposed prints, but they were not altered or distorted. From an evidentiary point of view, these fingerprints were not adversely affected. 2 figures.