With metals, it is often desired to have a reflective surface-not necessarily blindingly bright but one that catches the eye. Its relative reflectivity is much greater than surrounding surfaces. A gold leaf surface shimmers in the sunlight like a beacon when seen from a distance. It is as if the light is generated from the metal itself. Even on an overcast day, gold will appear remarkably bright. A zinc surface by contrast, dulled by oxide, reflects a blue-gray tone in bright light and looks the color of pewter in overcast sky.
The reflective nature of the surface of metals can be adjusted through the use of various processes. This is true of all metals. However, over time certain metals may change in reflectivity as the metals oxidize.
For this reason, some surfaces are limited in their choices. However, if desired, you can achieve a dull, flat, black appearance, devoid of the slightest visual sheen of any kind. Blackened by oxide, copper, zinc, and aluminum can have grainy, black, mottled surfaces. The mottling has degrees of black, some with a reddish tint, others with a gray tint.
- Zahner, L. Architectural Metal Surfaces. New York: John Wiley, 2004.
- Zahner, L. Architectural Metals: A Guide to the Selection, Specification and Performance. New York: John Wiley, 1995.