These inks sit on the surface of the water but they are difficult to move and the ink clogs up around the tool used to get a marble effect. They don’t fill the whole surface so you get blank areas on your paper. These inks are almost useless for marbeling
These are subtle, and you need to give them a good stir up front, then shake just before you use them, as the metal sinks fast. They show up best on dark backgrounds.