Eunjangdo

[Philip]

Originally Posted by Ren Ren

The problem is that "dohong" doesn't have a meaning in Korean. I had to strain to find out that "dohong" is a transcription of the Chinese term 烏銅 "wutong", which means "crow's copper" or "black copper". According to the Chinese treatise, it is an alloy consisting of 100 parts of copper and 1 part of gold. Thus, the Korean dohong, the Chinese wutong and the Japanese shakudo are the same copper alloy in composition. But there are differences in processing technique. For example, in Korea, the black color of the finished product is obtained by etching in urine (aged for a long time in a closed vessel).
It is also very interesting that the information that objects made of this alloy can signal the state of health of their owner finds some experimental confirmation.

Thank you for the interesting linguistic and technical information. A couple of comments:

The black color of the wutong / shakudo alloy is induced by a chemical process commonly called "pickling", the reaction causes a color change at the surface. Etching is the use of an acid to eat away (the English term "etch" is related from a Dutch word meaning "to eat") of the metal to create a pattern (contrived by the use of a resist like wax or shellac to block the corrosive effect in certain areas), or to dull a glossy surface, or to bring out the texture of the object by reacting with different constituent alloys (for instance, in revealing the structure of a damascus blade).

Regarding the alloy's use as a diagnostic tool -- somewhere in the past I read an article (can't remember where or when published) whose author stated that silver chopsticks were the norm at royal banquets because tarnishing during use could signal the presence of poison in the food.