jib Wrote:hi deb,
sorry , i was asking about blue light .. UV is invisible ( i was being daft )
jib

Yes, all three types of UV light are invisible to human eyes, however, as you alluded to, many things do glow (emit visible light) when exposed to UV light.
Scorpions, for one, glow under UV light. That's how people who study them look for them. They go out at night with a "black light" (UV light emitting tube) and point it towards the ground. Scorpions, when found, glow under the UV light.



Fred