Wow, I removed the LCD screen today so I could start working on a negative carrier and it is STUFFED. It's uhh... not supposed to be clear in the middle like that...
I couldn't see how bad it had gotten while it was installed in the projector, I did see some light leakage through the middle when projecting a black screen but looking at it on a light table I'm surprised it has been printing anything recognisable recently.
So that's another nail in the coffin of the digital UV projector idea I think, I might not even have run this screen with the UV light on for 100 hours and it's completely bleached. I don't think I could have given it any more cooling than I already am, and at the current UV power exposure times are still relatively long and inadequate for DAS carbon. I think the concept would still work for PVA-SbQ and silver gelatin due to their extreme sensitivity, but not for more traditional processes.
Of course the same thing could still happen to film negatives, but I guess the advantage there is A) exposure times will be much shorter and B) I can always produce another copy of the negative if the first one bleaches out/gets damaged.