Phil Jarrett , May 27, 2006; 03:25 p.m.
Ah... there's no magic in it, only Liquid Light - or similar. It's silver nitrate emulsion in liquid form that comes in a bottle, and you paint it on in total darkness or under a safe-light for some, allow to dry, then you can use it like regular paper. I'm a little sketchy on how you develop it. If it's on a flat piece of wood, then you can just put it in a deep tray, but you can paint it onto anything porous, wood, cloth (eg canvas).
I know Liquid Light is still readily available, but there were others. Could be some about somewhere. If you're in the UK, Fotospeed it as plain old Liquid Emulsion. However, if you're going to have a go, remember that this stuff it quite expensive. Fotospeed's is �33 for 250ml.