Chinese lacquer
Chinese lacquer , as Rhuslack , Urushi -Lack or Japanese lacquer ( Jap. 生漆 , Ki-urushi , literally "raw urushi") refers to is from the wound sap of the lacquer tree ( Rhus verniciflua even vernicifera Rhus , Jap. 漆の木 , Urushi no Ki ) as a viscous and gray-yellow product. The East Asian lacquer tree is related to the vinegar tree . This natural and toxic type of lacquer is the basis for traditional Chinese and Japanese lacquer art .
origin
The lacquer tree ( Rhus verniciflua Stokes ) occurs wildly in China, Japan and India. For the purpose of its use it was cultivated in China and Japan ( Honshū ).
Extraction of the raw substance
The raw material for Chinese lacquer is obtained from the resinous, gray-white, milky bark secretion of the lacquer tree. This is mainly found in the central and southern provinces of Anhui , Zhejiang , Fujian , Hubei , Sichuan and Guangxi .
To obtain paint, the trunks of the tree are scratched horizontally. The trees must ideally be at least 9 years old. The urushi-shōkunin (lacquer tappers) use a very sharp scoring sickle (kaki-gama) to scratch. A spoon-like instrument (natsu-bera) is used to scrape it out, with which they filled the raw varnish into a small bucket (gō) or a short bamboo tube. The hands protect the paint tappers with mittens (Te-bukuro).
The secretion turns brown very soon after removal and then hardens in a lengthy process. The quality depends on the one hand on the age of the tree - ten to fifteen years are ideal - but also on the nature of the soil, the climatic conditions, the harvest month and the care taken in processing.
In the next step, the lacquer juice is filtered with hemp towels and dehydrated and homogenized by gentle heating and stirring . Then the coloring with pigments takes place . The classic paint colors red and black were obtained by adding cinnabar or soot - which was later partly replaced by iron sulphate shavings. It was not until the 19th century that brown ( iron oxide ), green (mixture of indigo and malachite powder ) and yellow ( auripigment ) lacquer were produced. However, the exact shade depended to a large extent on the season.
History of Japanese lacquer art
Japanese lacquer work is known from the 3rd century. The height of this art is in the 17th century. The first concrete news came to Europe through Kaempfer (1712) and the Jesuit priest Pierre Nicolas d'Incarville (1760). The lacquer work was called “Nuri-mono” and “Urushi-saiku”.
properties
The raw lacquer is initially cloudy, but after curing due to polymerisation it is clear and very light to dark amber in color. Under the influence of the laccase enzyme , the milk juice obtained dries into a viscous mass. Before processing by the painter, the dried milk sap of the poisonous lacquer tree has to be cleaned and reworked. The technique is called urushi . For the application, different substances are mixed in with the paint and in this way different colors are achieved. These were carbon black , iron compounds, lead white , indigo , cinnabar , orpiment , gold and silver .
After drying, the paint shows great hardness, low brittleness and no shrinkage cracks. Its great resistance to common liquids (water, alcohol, ethers, acids, salt solutions) justifies its appreciation. The dry paint is waterproof and is hardly attacked by acids and bases. When fresh, the product is light gray-yellow in color. When drying, the color changes from dark brown to black.
The main chemical components are so-called urushiols . They harden at temperatures from 30 ° C and are resistant up to approx. 100 ° C.
Paint disease
Skin contact causes reddening of the affected areas and, as a result, blisters with liquid. In more severe cases, many parts of the body show swellings with severe itching. In addition, suppuration occurs. These phenomena are called lacquer disease (Urushi-Kaburé). Gloves are therefore worn and, in the event of direct skin contact, the affected areas are cleaned immediately and intensively.
literature
- A. Tschirch : The resins and the resin containers including the milk juices. Leipzig 1906.
Web links
- Urushi on materialarchiv.ch, accessed on February 10, 2017.
Individual evidence
- ↑ E. Kaempfer : Amoenitatum exoticarum politico-physico medicarum fasciculi V. Lemgoviae, 1712th
- ^ P. d'Incarville: Mémoire sure le Vernis de la Chine. In: Mém. de l'acad. roy. des sc. III. 1760, p. 117.