Three metals are associated with Greek and Roman sculptural tradition: gold, silver, and bronze. Other metals such as iron were produced in antiquity, but these were typically not used for statue production. The most common metal used for ancient statuary was bronze, an alloy consisting primarily of copper and tin.
By modifying the ratio of these metals, bronze could take on a variety of hues, ranging from nearly gold to almost black. Surface changes (patinas) also affected color. The green patina visible on many ancient bronzes, for instance, is a naturally occurring result of age and corrosion. Artificial patination, a chemical treatment of the surface, may have been intentionally applied by artists in order to manipulate the color of the bronze. Further color variation could be achieved through a combination of metals. Silver and copper inlays were often added to large bronze statues to emphasize details such as the eyes and lips.
Ancient statues made from bronze ranged in size from miniature to colossal. Gold and silver statuary, in contrast, tended to be smaller in scale, in large part due to the material value of precious metals. Gilding, the application of a thin layer of gold onto another material, such as bronze, stone, or wood, allowed for sculptures to appear gold. Gold was the most stable metal in terms of its color, as it doesn’t tarnish or develop a patina with age. Silver, in contrast, tarnishes easily and without continuous care turns black with age. In antiquity, silver was artificially tarnished to appear black. It is unclear to what extent this technique was used, but it was certainly used to articulate details on engraved and relief work.