I have been trying to dial in my exposure time, maybe one of you can help. I built a unit that uses ( f30watt t-8 blacklight lamps(although they do not look like traditional black light lamps when lit, but have the high uv output) My glass sits approx 5-1/4" above lamps. Any suggestions on an exposure time starting point? i have heard 40seconds to 5 minutes. Also any cheaper lamp alternatives as the lamps I use (Damar F30T8BL from Ryonet.com) are expensive. Any input would be spectacular. Thanks!