Copper and copper alloy can be oxidized gradually in air. The oxidixed film will go thicker, and its colour goes deeper assuming assuming deep brown or black,this antique and graceful colour comes from natural world is called the ancient copper.

on the basis of ancient copper, the scienfific research personnel of our company study by heart and set up a change colour, plate with expensive matel, so increase the types and colour and so make the "Kaide" workship to be works of art, whose value is more than the price.