confused about florescence, Ultra Violet light, and black lights.?

Question

So... for a while I thought I had it all figured out. I decided that UV was within the visible spectrum, because florescent things glowed under black lights. I figured that they were all the same. But... they aren't. So now I'm completely confused. What is florescence, how does ultra violet light differ from the light emitted by black lights? Do both Ultra violet and blacklights make florescent things glow? I have a pretty good understanding about light, photons, and colors... but this is a rough spot. Shed some "light" on the subject please.

Answer 1

Hi, a black light is producing a range of EMF which contains UV emissions, but also some high violet which you can see. When the UV light makes something fluoresce, you are not seeing the UV light reflected, but a lower wavelength of light which is emitted from the object. When the light energy hits the object it excites an electron and pops it to a higher energy level. When the electron pops back to it's stable state, multiple photons at different energies are released. So, you're not seeing the original UV light, but a by product of it, that's why only certain materials are fluorescent and to specific wavelengths of light.