In addition to our completely invisible Blue ink that becomes highly visible under 365nm UV (Blacklight) illumination, we also have other inks that are highly UV fluorescent while having a very low visible image under normal light.
While these inks are not completely invisible under normal light, they are very difficult to see without UV Light. The inks are great for hand stamps and other uses where the background is not pure white. On a clean sheet of white paper, these inks will leave a visible stain unlike or invisible blue ink. On human skin or many other surfaces, the ink will be invisible or difficult to see.
Under UV illumination, these inks will fluoresce quite brightly. The colored UV inks are only available in our 2 OZ bottle sizes.