Country House in Greifensee/Switzerland
In its mill-finished state, copper has a reddish hue, which naturally oxidizes to a dark brown colour when exposed to the atmosphere. To achieve the surface coloration that develops naturally only after about six to eight months, even during installation, the surface of copper components can be burnished, i.e., chemically dyed brown. A natural patina protective layer develops over time on both naturally oxidized and chemically dyed copper surfaces. On vertical building components, this patina protective layer is often not green, as on towers and roofs, but rather a deep brown to anthracite grey.
