I love this photo and I have been trying all kinds of mixtures to get it to do this but I just cant get it down. Any clue? http://www.popescoo.net/alin/main.php?g2_itemId=136
Basically the photographer has used two chemicals that don't mix i.e. water and oil, same situation if you try to wash your oily paint brush in water or at least the same principle. You could maybe try mineral turps in the glass and a blob of something water based. Worth a try !!
Pick up some liquid food colors at your food market. In a still glass of water, gently add a drop of one of the colors. With a thin rod [skewer, chop stick, etc.], gently stir the water a little bit along the outside of the glass. Observe. Go from there.
