ALUM (
Potassium aluminum sulfate): Crystalline white acid mordant circa 7800 BC in the Mid-East. Best on wool, silk, mohair. Rinse thoroughly to remove all alum; too much alum will rot fiber. Use for pre-treating fabric before marbling so designs transfer well and to draw marbling colors off the gel onto fiber. Alum garden fertilizer often has added ingredients, including iron.
Amount: 4oz
