Here's how to get the effect with the acrylic inks (which by the way are the kind used with an airbrush - they come in a bottle with a dropper built in the lid).
Use good-quality watercolour paper and wet it thoroughly both sides. We brushed the water on with a 1" brush - and it takes much more water than you think as the paper soaks up a lot!
Then drop the inks on - any colour from any height - they immediately fan out into the most amazing shapes!
Then FLOAT the cling film (Saran Wrap) down on to the paper - it needs to be larger than the paper. Then play - bunch the cling film up leaving some air bubbles, drag the inks through the film, gently rub circles through the film - anything goes!
Then leave it to dry. Overnight is best, but we didn't have that luxury in class so we air dried them near the radiator.
After about an hour we gently peeled back the cling film. Where it had stuck to the inks, you get the amazing sheen. Where there were air bubbles and crinkles you get the amazing organic shapes of leaves and feathers. One woman had a distinct frog on hers, another a dragonfly, me - a tudor lady :o)
Let me know if any of you try it and be sure to post your results so we can all enjoy!!