How to collect Urushi sap lacquer
Urushi is the sap exuded from the Urushi lacquer tree. The tree yields this milky-white sap to heal wounds (a broken branch or damage by insects or animals). If the sap is not removed immediately, the resin becomes dark and hardens over time, like human blood. The Urushi tree protects itself with its resin.
Characteristics of UrushiUnlike paint which dries by evaporation, Urushi dries by a chemical reaction which provokes hardening by oxidation with moisture from the air and polymerization. The appropriate temperature (15 - 20 degrees C) and humidity (70 - 90%) are necessary to provoke this reaction. Under these conditions urushiol and laccase, components of Urushi, react chemically to generate a coating film. Once hardened it becomes a tough coating, very resistant to high heat and to the action of acid, alkali and alcohol. The drying process may require from a few to a dozen hours. If the correct conditions of temperature and humidity are not met, it may take more than one month to dry. That is why it is much easier to dry the Urushi lacquer in the humid rainy season than in the dry winter season. After each application the object is placed in a special drying cabinet which maintains a temperature and relative humidity appropriate for the proper hardening of the lacquer. This requires great experience and skill. Due to these conditions, the drying process is much more complicated than the painting process. It may also affect the quality of the coating, such as its color and brilliance. Normally, with paint, deterioration can be observed immediately after the painting is finished whereas Urushi's rich, smooth, beautiful coating will intensify in brilliance and color with time.
Urushi in JapanInitially Urushi was used as an adhesive for weapons and implements used in hunting. Later Urushi lacquer was developed as a coating for decorative objects, adding creativity and refinement to the advantages of its protective and resistant nature. It is said that the word URUSHI was derived from the words "URUWASHI - meaning beautiful" and "URUOSHI - meaning moisture" because of the shininess of its surface. The Chinese character representing the word "Urushi" contains symbols for water, tree and man, which explain well the characteristics of Urushi. Urushi's unique texture and brilliance match the Japanese people's sense of beauty which led them to develop Urushi lacquer ware. Through its long history Urushi lacquer ware has fascinated not only the Japanese people but also many people around the world.