that's true,.. ...and don't change UV with purple! if you want to use uv-reactive-paint, you've gut to use only UV-LEDs, 'cause if you use purple LEDs the purple light will be so bright, and the UV-part will be so small, so you won't recognize your UV-reactive paint glow. And, btw, be sure not to use LEDs with wavelengths below 300nm! those rays are called UV-B radiation and are dangerous for your skin and eyes! Especially when the ambient light is dimmed and your pupils will open to let more light on your retina, there will also be more of the dangerous UV-B light damaging your eyes. It's the same thing with wearing cheap sunglasses with no UV-protection on a sunny day. "Oh my god, you're so tanned! Have you been to a solarium?" "No, I had a gig with my midibox yesterday evening" ;)