Hello, I was hoping someone could help me with my problem. I built a very low budget exposure unit for alt printing. I used flouresents from Kmart, took off the difuser and cut off the sides. I then replaced the bulbs with BL bulbs from bulbman. When I did this a couple of years ago my times were and acceptable 15 minutes or so. Then, last year, my times began to climb to 40 minutes to an hour. I can't figure it out. Then I realized that it may be the glass. I changed out my original print frame glass when it got scratched with glass from a glass company. Does anyone know if that could be the problem? Could it be blocking UV? It's cloudy outside and I'd really like to get to the bottom of this so I can print again.