In order to have ebru colors to spread on the surface of the liquid and to prevent them from sinking, we use ox gall, which is a surface active substance, breaking and regulating the surface tension. It also prevents colors from blending. Gall is a secretion of the liver, involved in the digestion of lipids.
Great customer service. I contacted the seller with a question, and received a prompt reply. Item shipped quickly, and very well packaged. Will buy again