Here: https://trumpetpower.com/photos/Exposure is a first attempt at a document I've been meaning to write for a while. I'm afraid I don't have the time right now to further put into refining it; it's much too long and ideally needs to be broken apart and probably have different parts re-written multiple times tailored for different audiences -- and I *really* don't have the time for that sort of thing. But, still, I hope it answers many of the questions I've had asked of me of late Cheers, b&