Yesterday I was hunting around looking for background techniques for art journaling. I've completely run out of paint (acrylic) so I have to try and utilize what I have left, which is pretty much water colour paints and oil paints. I remembered hearing about a water colour paint technique where you fill your page with colour and before it dries, cover it loosely with Glad Wrap (cling film). I decided to give it a try and was pretty pleased with the results! Not sure what to do with the page so for now I'll just add it to my stash. The next technique I'd like to try is using water colour paints and rock salt, and then maybe both at the same time!
Edit: I left the cling film on the painting until the paint was completely dry. It was a warm day here, so I left it on for about 6 hours. The paint was dry, but the actual page was still a little damp. I have read though that you should leave the cling film on overnight.