> There is a clear watery ink used (absorbent pad and rubber stamp) to make > a mark on the back of someone's hand to indicate "paid" admission at the > swimming pool. > It's quite waterproof and hopefully non-toxic. It has no visible colour under > daylight or normal light, but shows up brilliantly under near UV. Perhaps it > could be added to a compatible solvent paint of any colour, to add UV > reflectance. You are confusing fluorescence with UV reflectance. What is wanted is paint that will reflect UV, rather than emit visible light when illuminated with UV. -- Malcolm Roe Phone : +44 442 230000 ext 4104 Crosfield Electronics Ltd Fax : +44 442 232301 Hemel Hempstead, Herts. HP2 7RH, UK E-mail : [log in to unmask] ------------------------------------------------------------------------