The English word “patina” derives from the Greek term for dish; and refers to the tray, often bronze, which was used to distribute the host during the eucharist. Because such trays became venerable and precious for their association with the body of Christ, they were preserved over long periods of time, thus, developing the signs of age: that particular mottled green surface of old bronze, along with the signs of use and wear.
Patina results when the surface of a metal is altered by the effects of the atmosphere, causing gradual changes which initially tarnish the metal with an uneven coloring; eventually causing the whole surface to convert into a basic mineral product typically green in color. Sometimes referred to as natural toning, a patina was once only achieved with the passing of time.
In history, impermanent patina induced by seawater was used in excess by Greek artists as a colorant. It was called verdigris which literally means “green of Greece,” but in modern times it is often shortened to Verde or Verdi. It was considered the brightest green pigment available. Patina today is most commonly used to refer to the green corrosion products that form in time on copper and copper alloys such as bronze when it is exposed to the open air or to burial conditions. The meaning of the word is relatively recent and it is believed originated in the mid-18th century when the field of archeology had begun to develop, along with admiration of the colored corrosion products.
Interest in metalworking has had many revivals of earlier periods, such as classicism, but more so in renaissance Italy and the Chin dynasty in 12th century China. Ancient artifacts of earlier periods have been diligently collected and studied and have kindled a desire to imitate the natural patination as a finishing process for contemporary work.
The finest tradition of metal coloring and patination was that of the Japanese. The rich history of Japanese patinas is the result of hundreds of years of experimentation, innovation and tradition. Their metallurgy probably originated in China and Korea, but the development and use of non-ferrous copper-based alloys, particularly during the 15th and 16th centuries, was unrivalled. Though the history of metalworking is relatively young in Japan, Japanese craftsmen have developed alloys and the art of patination further than any other metalworking culture in the world.
Today, to patinate their work, jewelry artists employ a huge palette of homemade recipes, commercial products, and methodologies. These solutions can be sprayed, brushed, dipped, dabbed, or wiped onto the metal, which is usually cleaned in an acid solution or on a finishing wheel prior to (and often during and after) application. The work is then dried by air, heating, or baking, and is often sealed with a spray fixative (usually a clear lacquer), a wax, or a varnish. The processes vary by artist, as do the choice of materials, thus, adding a sense of mood and drama to an object, to enhance and highlight detail or to accelerate the ageing process.
Artists have been using patina since, at least the 1800s. Sculptor, Auguste Rodin used patinas on many of his bronze pieces. Likewise, American western artist Frederick Remington, used patinas on his twenty-two famous statues depicting cowboy and western American life.
The most famous example of copper patina is the Statue of Liberty. This notable New York harbor landmark is known for its bright green patina. Few remember seeing its original copper color. Over a long period of time the copper reacted to the local climate by oxidizing, producing the protective green patina seen today.