Homemade PCBs fluorescent?

I've been making homemade PCBs for the last few years and it never occurred to me that the board itself would be fluorescent. I was using a scrap of clad board (with copper etched off) as a backstop for my 355nm laser when I realized the board fluoresces pretty bright. Since I don't have a blu-ray at the moment, can anyone else verify this?

It may also be worth noting that my board was etched with ferric chloride.

Positive. But i cant tell if its epoxy or cardboard PCB. Gives a nice cold-white glow...