> How is the sensitivity to low light? Can you align and get ready > for photomask exposure with a 60 watt incandescent light in the > room?
My basement uses 100w compact fluorescent bulbs, and there are a couple of windows. I take care with the roll of unused film, keeping it in a blackout bag within the cardboard tube, and limit its exposure to room light (often shutting the lights off to remove and cut it). However, I haven't noticed any problems with the individual pieces of film I use. And, that includes time to laminate it, which I do by hand with water, a squeegie, and a heat gun (Adam Seychell's "wet lamination" method). I think the trick is to calibrate the UV exposure based on your *actual* process, so all that gets taken into account. As for alignment, I use a paper print to drill out some alignment holes, and a special footprint for an alignment target that results in a fine cross-hair on the print, which I just line up with the hole. I do the alignment on the UV tray, then place the glass atop it and verify that it's still lined up, then expose. Note that the alignment is so easy, as well as the other steps being robust enough, that you always etch both sides at the same time. No need to do one side at a time. To get started, you'll need: * A UV exposure source. Mine uses UV LEDs from eBay (BestHongKong, ~390nm) http://www.delorie.com/pcb/uvled/ * Photofilm. http://www.pcbhobbyist.com/ * heat gun. Anything will do, but not a hair dryer! * chemicals: sodium carbonate (washing soda, in the laundry isle of your supermarket, NOT baking soda) and sodium hydroxide (aka "lye", hardware stores). * a sink, an old credit card (squeegie), paper towels, etc. _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
