Laura Leeder was here on the weekend to learn this gorgeous technique, which I learned from Alice Saltiel-Marshall last fall. You can see Alice's blog about this technique (and others) here. I've since incorporated it into my Mixed Media II - More Playtime for Adults workshop. It's fast becoming a favourite.
Here, I've taped a piece of 140 lb. cold-pressed watercolour paper to a sheet of butcher paper sitting over top of a thick piece of cardboard (plywood or gator board works better than cardboard, though!).
I've started pinning bits of cobwebbing (available from craft and dollar stores around Halloween) across the paper, taking care to keep it thinly spread in an interesting design.
Unfortunately, due to a camera fail (likely due to a 1d10T error), I was unable to capture a photo of Laura's finished piece, a lovely one indeed. You may want to keep your eye on her blog to see if she writes about her experience!
Just a note that if you're testing this out, and use watercolours rather than acrylics or inks, you'll want to finish off with a couple of good sprays with workable fixative before working over top of it. However you do it, it's bound to be beautiful. I KNOW there will be a run on cobwebbing wherever I am this Halloween!