A primer formulated with a colorless dye detectable only under black light is provided. The present invention is non-detectable on a porous surface and color does not appear over time upon exposure to natural or synthetic lights. Under black light, sometimes referred to as ultra violet energy or long wave black light, the colorless dye appears as purple. However, once the black light is removed, the primer ceases to glow and returns to its natural, colorless state.