Juglans: Tannin Ink and Magic Formula for Hair Dyeing

Black walnut is a Juglans tree native to the North America plains. It features a tall and dense canopy up to 20 or 30 m high. The timber is dense and hard, making it suitable for woodworks. The natural dark color and beautiful grain are usually preserved in woodworks to reveal its unique chocolate hue. Black walnut was introduced to Europe at the beginning of the 17th century. Since then, it has become a very precious wood in traditional furniture-making. It commands a prominent position in antique furniture, and is often used as a building material in churches and castles, as well as an interior decorative material in luxury automobiles (Fig. 1). Black walnut is also the traditional wood used for gun stocks. During the Age of Industrialization, it was used as temporary utility poles when laying railways. An iron nail or ironware on the trunk of a black walnut or walnut will darken the color of the wood. Therefore, iron products are often found in black walnut logs. This is an interesting phenomenon that will be discussed later in section 5 regarding mordant. Black walnut is a fine tree species with high economic value. Its fruit is edible, and its trunk can be used for making wooden wares. Western artisans have found an additional use of black walnut, i.e. its green hulls can be processed into brown ink. As the oxidation time increases, the ink color gradually darkens. This makes black walnut become a raw material in the early production of ink.