And that was it. The earliest stains were rhodamine. Investigators had to mix their own solutions and there was questionable safety about working with them. Safer mixtures, such as long-wave UV light used with the stain ardrox, provides a simple method of visualizing latent prints. Powders are now catalogued by major crime scene equipment suppliers that luminesce under various forensic light sources.
Powders are available for magnetic as well as brush application.
A variety of colors is available so the investigator can use what best fits the situation. There is even a bi-chromatic powder that appears silver on a dark background and black on a light background. You can spray it on a wet surface and the particles stock to the latent, emphasizing it for photography or lifting. A more durable solution is using silicone rubber as a lifting medium. Recent developments have put many new tools in the technician's kit for latent fingerprint processing.