Dó paper is a paper made from the bark of the Rhamnoneuron balansae traditionally produced in many villages in Vietnam. It plays an important role in folk art, Dong Ho Painting in particular, because of its durability.
The production process includes some stages. First, the bark is soaked in limewater for three months. Second, the black outer bark is husked off and ground by mortar and pestle before being blended with a viscous substance made from a plant belonging to Verbenaceae family. This mixture is diluted to form a slurry. A bamboo mold (Vietnamese: liềm xeo) is dipped into the vat of slurry and removed. Paper fibers adhere to the mold in a thin sheet that is then pressed, dried, rolled, and dried again. The final product must be soft, light, and durable.
Due to its durability, this paper found many uses in traditional Vietnam, including the making of books, paintings, and documents.