patinate

Patinate is a verb meaning to cause a surface to acquire patina, or to become patinated through natural aging. A patina is a thin, often translucent layer that forms on metals such as copper, bronze, brass, and sometimes steel, as a result of chemical change at the surface. The layer can range in color from green and blue to brown, black, or iridescent tones, and may provide some corrosion protection while indicating age or use. The process can occur naturally over years or be induced artificially to achieve a desired aesthetic or protective effect.

Natural patination develops through exposure to moisture, oxygen, pollutants, and salts, and can be influenced by temperature, humidity, and environmental conditions. Artificial patination uses chemical treatments or controlled heating to create specific colors or textures. Common methods include applying sulfide or sulfate solutions, nitrates, or ammonia-based compounds, and regulating temperature or time to control hue and uniformity. The resulting patina is typically a stable, adherent film.

Patinating is widely used by sculptors, metalworkers, and in architectural finishes to obtain antique or sculptural appearances. In conservation, the patina is often valued as part of a piece's history and can affect handling and cleaning decisions; removing or altering a patina can reduce historical integrity or value. Safety concerns include proper ventilation and protective gear when using chemical baths.

A related term is patina as the noun for the achieved surface layer; patinated refers to objects bearing such a surface. In jewelry, art, and architectural bronze and copper works, patination is an established technique for achieving color and texture.