I imagine the exposure time would be so crazily fast that you wouldn't be able to do anything but overexpose the hell out of the screen.
I mean, you tan faster in those things than you do in the sun... and on a bright day you're looking at less than a minute of exposure time. So those bastards would probably have an exposure time of about 10 seconds or less.
I could see that, though.
"Hi, I'm here for my free trial tan."
"Uhh... what is the you're holding?"
"It's my security screen. Kind of like a security blanket, but screenier."
sounds like more trouble than its worth. i have never been to a tanning salon but i believe there is lights on both sides of the bed. so light is hitting your screen at all angles. you would need something backing the print side of your screen and something holding your films down. the bag methos i use would be good for it but still i would just rather burn in the sun. its the greatest source of UV light there is.