Hi Kerry - Actually, except for the sample that is black on white paper (Japanese method - ink on water), the rest are done on a gelatinous bath. Colors used are water-based, acrylic and oil. I used to mix and sell my own colors and tools. Finding the right paper is a personal choice. I also worked with hand-made paper. Whew, this was a lifetime ago. I think floating cocoa butter/oil-based colors on chocolate might work. The suspension of one material on top of another is called surface retention - from physics! If the cocoa butter/colors is thick (have not worked with it yet), then you would be able to manipulate the colors to produce a pattern. If not, I'm sure a random design would be produced. Thinning or thickening a color would also affect color manipulation. I know with paints, each color would react differently because of what they were made of. Not sure if this follows for cocoa butter/oil-based colors. When I start experimenting, I will post results, good and bad!