Patina is a technical term in antique industry, which refers to the oxide layer formed on the surface of cultural relics due to long-term oxidation. "patina" is actually "luster", which refers to the natural luster formed on the surface of antique objects through years and months. Not only porcelain, but also paper and silk products such as wood, jade, bronze, tooth carving, Wan Wen, calligraphy and painting, stele extension, etc.
Because the patina supports the years, the older things are, the thicker the patina is. For a simple example, the newly bought bamboo mat, no matter how smooth it is polished, has no patina, while the bamboo mat that grandma has slept for 50 years is bright red. There is no patina on the handle of the new hoe, but there is patina on the handle of the old farmer.
Causes of copper rust
This luster is similar to that of varnish, but it is not the floating light produced by varnish, wax, coconut oil and leather shoes oil. It is cleaner and deeper, which makes bamboo, wood, porcelain, stone and other non-jade things present jade-like gems and aura. This is what collectors call "open patina".
There is no monograph devoted to the reasons for the "patina" of antiques handed down from ancient times. It has been mentioned in some books that some high-grade wood, such as rosewood, mahogany, Huang Huali and tieli wood, has some oil, which seeps out over the years and blends with dust in the air and sweat stains touched by people to form "patina"? .
This statement seems to have some scientific truth. What about jade, Yin Shi, bronze, inkstone and porcelain? Especially the rare books and calligraphy and painting handed down from ancient times. These antique works of art are not "oily" in themselves, but they also have "patina", which is even more puzzling.
But the fact is that "patina" does appear on these handed down non-oily antiques, but compared with wooden furniture, it is even less known and more difficult to distinguish. In particular, the "patina" of porcelain is even more difficult to identify.