Years ago I put together a PCB exposure system with black light white tubes. They're the same as black light tubes but without the additional purple filter to remove the visible light. It was an F20T12-BL, the purple is the F20T12-BLB and BLB stands for "Black Light Blue".

Those worked great, fast exposure. I could see everything that was going on clearly due to their white component. I think they were cheaper than purple black light tubes too. One of these tubes has died, it's flickering.

I went back to Home Depot and it appears they no longer carry this tube, only purple filtered black lights. They do carry "grow lights" of the same size. I don't suppose these are the same thing, are they?

Ive been using a really cheap halogen desk lamp for exposure with the UV filter removed and it works great. Just another option :lol:

Try these folks. They may have, or be able to get, what you need.
http://www.specialtyoptical.com/catalog/
JB