Durability of wooden shop-name signage coated with Urushi lacquer and gold leaf attached to the facade of building in Japan
K Yamamoto, M Kiguchi
Wooden shop-name signage plated with gold leaf is one of the characteristics of newly developed westernized commercial buildings appeared after the Great Kanto earthquake of 1923 in Japan. The signage still remains mainly in old districts. The signage with independent letters (Chinese character) shows off the name of the shop with golden colour on the façade of building. The number of these shops sign on the wooden signage has been decreasing quickly during past 2 decades because of the re-development of city or so called “doughnut phenomenon” of city. Before the extinction of all of the wooden signages, we examined 195 signages attached in various types of building to elucidate wood species, manufacturing process, maintenance method, and aboveground dulability of them. Service life of them sign on the facade of shop at 3-4m aboveground seemed to be around 30 years without maintenance, and complete separation of the gold leaf required tens of year. Separation of the gold leaf from the surface of Urushi lacquer progressed gradually for a long time, and the Urushi lacquer layers appeared under the gold leaf for another several decades until all of gold leaf peeled off. After that, it decayed very quickly. The wooden shop-name signage plated with gold leaf has the advantage of appearance and durability, but it would die out in course of time. A traditional use and technology of the wooden signage with gold should be recognized widely at least among people in the wood industry.
Keywords: durability, aboveground, building, wooden signage, Urushi lacquer, gold leaf