3'x5',copper sheet- patina etched colors, 2008, 1x4" wood support system. This work installations interior or exterior, all-weather. Copper is rather permanent yet is always oxidizing. I never wanted to cover these metal sheets preferring the surface to be touchable. I've completed 15 such sheets of metal on brass, bronze, and copper. A light coat of fixative is used to completely stop the acid etching process. Copper turns darker pecan colors in aging. Turquoise colors are cupric nitrate in concentrations that are not harmful or delicate.