Fluorescent Latent Print Powders may be used on the same surface types as non-fluorescent powders. Fluorescent latent print powders work especially well on dark or multicolored surfaces—greatly enhancing ridge details when illuminated with an ultraviolet light. Typically, light in the ultraviolet or blue parts of the spectrum (254nm to 525nm) is used to excite the fluorescence. LL703 is 2 oz. Green Fluorescent Latent Powder.