Vaughn: I used 8 black light tubes (30 watts each) and the distance between the tubes and the exposure plane is about 6 inches.

Rick: Thanks much for the link!

Loris: Thanks so much for the detail instruction!

WetMogwai: Thanks much for sharing the experience. I'll look for a hake brush and have a try.

Sorry for the late reply. I replied twice since the day before yesterday. But I don't know why it couldn't get approved to be posted. Not sure if it can be approved this time.