Yellow Fluorescent Powder produces brilliant fluorescence when exposed to a forensic light source. The resulting latent fingerprint should be photographed with the light source prior to lifting. This lightweight fluorescent powder should be applied with a White Feather Brush. Black backing cards or gellifters may be used to provide a sharp contrast with the resulting ridge detail. NOTE: To prevent clumping, our powders include a desiccant canister inside each jar with a capacity for absorbing moisture.