Shadow and High Key Contact Printing

I stumbled across the terms Shadow Printing and High Key printing in the context of making contact negatives (ok I'll admit it, it's part of a workshop that, for logistical reasons, I'll never be able to attend). Is this a new idea or an old one? Can someone explain this technique and theory in general terms? Does it involve making two or more seps instead of a single negative?

~m
Received on Thu Mar 16 10:57:41 2006