Originally Posted by IronWing
I think I already have answer to my first question which is yes. I've been photographing fluorescent minerals (glow visible light under UV light source) lately and have been getting a blue wash over the specimens. It is most noticeable using long wave UV (368nm also called UV-A) and worse on flat surfaces facing the camera. I suspect that the camera sensor is picking up reflected UV light and interpreting it as blue. Would a UV haze filter on the lens cut the reflection?
Below is an extreme example. To the naked eye there is no blue showing on this specimen other than a few dust specs. I'm using a Nikon D90 and a Panasonic LX5 with similar results.
Digital sensors are mostly, but not entirely, immune to UV light.
If you want a UV filter, try one with good multi-coatings and good blockage of UV light. The best choice for you is probably the cheap-but-effective Hoya HMC UV-0 aka UV(0). http://www.lenstip.com/index.php?art=113&roz=15
If you can't find that type, get the UV(c) instead; it's almost the same as the older UV(0) version except that the filter ring is thinner on the UV(c) type.
If you don't mind spending a little extra, I can recommend through personal experience the Hoya HD (harder, thinner, easier to clean version of the Hoya HMC). Unfortunately B+W filters do not block out enough UV light to make the cut, else I'd recommend those, too.
You can see the test results for other brands of UV filters here: