A.: Not Always. It depends on the atmosphere and weather conditions. Bronze, like any copper alloy, will age and tarnish. In Upstate New York, bronze screening will usually darken gradually over a period of years, eventually turning black. In a more corrosive environment like the oceanfront in Cape May, New Jersey, the salty, moist sea air will turn bronze screen green rapidly, within a few months. Protection from porch roofs or nearby buildings will slow this progression. It’s a location/environment specific process.