A cooper-plate engraving artwork titled Red Phoenix Flying through the Sun is shown at the book fair. [Photo by Zhang Xingjian/chinadaily.com.cn]

Copper-plate Engraving

"What is this, mom?" a visiting girl curiously asked.

"I don't know, either, maybe you should ask the artist sitting there," the girl's mother suggested.

"It is called copper-plate engraving, a folk art with a history of more than 3,000 years," Hai Jun said, founder of Folk Copper-plate Engraving Workshop.

Copper etching is a selective removal process used to create images on a copper plate. Most etching processes require a plate covered in a nonreactive material that is then selectively removed. The plate is exposed to a corrosive that removes small amounts of copper while leaving the protected areas alone.

"In the past, it was done with wax and different acids while modern copper etching generally uses less toxic materials such as ferric chloride instead of acid and sodium carbonate to remove it. Modern etching is used for everything from artistic expression to creating ink prints to laying pathways on circuit boards," said Hai.

"Delicate as they are, it requires too much time and energy to make one. Due to the advancement of modern technology, many insiders have abandoned the traditional hand-made way and resort to industrialized production. However, there is a great difference in the quality of the product of the two processes, " Hai added.