Although gentian violet (GV) has been used for many years as a dye stain for producing purple-colored prints, reports of the deep red to near infrared fluorescence of gentian violet-treated prints have been a relatively recent observation. The work reported in this paper has built on this initial observation through the systematic examination of GV fluorescence properties and produced a more reliable procedure for obtaining such fluorescence from latent prints. To aid the method, a relatively inexpensive system for viewing this fluorescence was developed by using commercially available off-the-shelf items, thereby providing the latent print examiner with a complete system for detecting prints on traditionally difficult surfaces such as dark sticky tape. This system provides better images of GV-treated prints on dark surfaces than visible or conventional photographic images and does not require any modifications. Weakly developed gentian violet prints, which do not produce a visible reaction, may still be visualized through fluorescence by using the system described in this paper. 8 figures and 24 references