Cov xim tsis pom cov hmoov reacts nyob rau hauv ultraviolet rays.thaum nyob rau hauv uv teeb, yuav hloov ci ntsa iab heev!
invisible pigment kuj hu ua uv pom tsis pom pigment, UV fluorescent hmoov.
lawv muaj ntau daim ntawv thov, cov ntawv thov tseem ceeb yog nyob rau hauv kev tiv thaiv cuav inks thiab lately kuj nyob rau hauv zam faib.