I’ve liked shadowpainting for some time now, but never seem to use the latex-based masking fluid before it all gunges up in the bottle. It helpfully says on the label to dilute with ammonia to get it liquid again… but I just don’t seem to have that lying around!
Meanwhile, I’ve used WOW! Bright White embossing powder on watercolour paper to do much the same thing – it’s a lot quicker as well using a stamp rather than tracing patterns with latex gunk and waiting for that to set. I’ve used Distress Inks (from reinkers) to colour each of the images. I’ll be teaching the technique at the Manic Stamper Craft Club in Leicester on Saturday 🙂