I am looking for a new slide projection screen: I have a fairly large number of slides, and the old screen that I have was salvaged secondhand from an office and is now somewhat broken and rumpled. What exactly ought one be looking for in a good projection screen? Is there much of a variation of quality, or is any half-decent screen as good as the next? Can anyone recommend any UK resellers? Thank you in advance Edit: These look good - any comments?