Crystal Violet

Use Crystal Violet to develop latent fingerprints on the adhesive side of almost any kind of tape, Scotch, electrical, Kraft, etc. Mix the powder in water, soak the tape in the solution and rinse with running tap water. The caution about working with Crystal Violet powder or solution is that it is a very messy dye and will stain skin, clothes, floors and counter tops. It may be very difficult, if not impossible, to remove the stains from some clothing, furniture and floor covering.