Cryptolyte is a translucent liquid additive that causes cured Smooth-On^® silicone rubbers, urethane rubbers, plastics or foams to glow a bright blue under a focused ultra violet light source (blacklight). You will not see the glow effect without an UV light source. When mixed at low percentages it will not affect clarity or color of material. For example, Cryptolyte can be added to Crystal Clear™ resins and the glow effect will not be evident until the casting is illuminated by a UV light source. Applications include special effects, Halloween mask and prop making, theme displays and security.