Coats Of Many Colors

By applying patinas, designers can bring new textures to their work – and add a few surprises.

Examine a pair of hinged earrings by Sparklynn Designs in Springfield, Missouri, and you’ll see colors: earthy browns, smoldering reds, and faded turquoise. Only hairline brushstrokes of the original silver remain. The surface of the metal appears buffed by age or smoothed by much handling.

In the work of Santa Cruz, California-based designer and workshop teacher Carol Webb, silver has been rendered a perfect black-and looks as if it had always been that way. Gold, along with geometric areas of unchanged silver, stands out against the dark backdrop in contrast.

Both the dramatic starkness of Webb’s work and the weathered colors of Sparklynn’s designs are examples of patination, one of many ways in which color can be applied to metal. While patinas will naturally form over time on most copper-bearing metals, the process can be hastened-and heightened-through a combination of chemistry, heat, and artistry.

“Patinas bring a graphic component to the jewelry, a visual texture,” Webb says. “It lets me explore the relationship between pattern and form.”

And those added textures could lead to surprises, says Lee Rumsey Haga, a jewelry artist and college teacher in Portland, Oregon. “[People] assume that metal is going to be either gold or silver toned, and to have a shocking blue or green-that makes people look again and think, ‘What a mysterious metal this is!’ It adds to the magic of metal, that it can change color like a chameleon. I also think that patination gives my pieces a more antique quality, which I want.”

The solutions and methods used in creating such magic are as numerous as the colors and effects they achieve. But in the end, they all come down to a basic chemical process, in which a mineral compound is formed that’s natural to the affected metal. Rusting is a classic example.

“In the studio, we trigger this natural chemical reaction by using a chemical and, in some cases, heat. Oxides and sulfides then form on the metal like layers of skin,” describes Tim McCreight, a jewelry maker and teacher at the Maine College of Art, whose forthcoming book Color on Metal devotes a section to patinas.

However, not all metals take similarly to the process. Patinas are most often associated with metals that become unstable in air. Because of the many valence electrons in their outer shells, these metals more easily combine with elements such as oxygen and sulfur to form new, colored compounds. In the art world, patinas are most often created on copper and its alloys, brass and bronze, as well as on silver. Gold and platinum, which do not oxidize in air, do not patina well. Neither do tin, lead, aluminum, or zinc.

To patinate their work, jewelry artists employ a huge palette of homemade recipes, commercial products, and methodologies. For example, The Colouring, Bronzing, and Patination of Metals by Michael Rowe and Richard Hughes-the best patina book to date, according to many educators in the field-includes 1,126 recipes.

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. But the results, as Haga says, always offer a surprise.

Silver Linings
Liver of sulfur (potassium sulfide) is the most popular patina solution in the jewelry world, particularly for silver, notes Gene Pijanowski, a jewelry maker and educator at the University of Michigan in Ann Arbor. Applying liver of sulfur on silver causes a chemical reaction that converts the surface to silver sulfide. With repeated applications (or more time left soaking in the solution), the sulfide darkens to black through a series of color changes that
include yellow, orange, brown, red, purple blue, green, and gray.

“The reason you see color differences has to do with the way light bounces off the layered patina,” explains McCreight. Lighter colors reflect off a thin, transitory film, which can be more easily worn away with handling. The thicker the layers of patina, however, the darker and more stable the color achieved.

Husband-and-wife team Chris Lynn and Paula Sparks of Sparklynn Designs use liver of sulfur as their primary patina chemical because of its flexible color range. Working predominantly in silver, Lynn and Sparks have created an organic-looking line of earrings, pin/pendants, neckpieces, and bracelets, all of which incorporate gems such as ruby and zoisite to playoff the multicolored patinas.

“Depending on the strength of the solution and the heat applied, I can create colors [such as] canary yellow, turquoise, magenta, and olive green, as well as grays and blacks,” says Lynn. “I run the silver under hot water [120°F to 150°F] to warm it, paint on a layer of liver of sulfur, rinse it off; paint again, and apply varying layers or concentrations of solution in various spots to achieve a rainbow of colors.”

How long Lynn leaves on the patina solution depends on the color he wants to achieve. “Sometimes it is a matter of seconds to several minutes to half an hour,” he says. “The shorter the time, the lighter the color.”

Because patinas on jewelry more easily wear due to abrasion and frequent contact with the oils and salt in our bodies, they are perhaps better suited for ornamental items, warns Pijanowski. Lynn also notes the fragility of patinas, especially in the lighter colors, and does not incorporate them in high wear areas, such as the neck or the wrist; he limits his use of patinas to earrings and pin/pendants. Different textures in metal, with a patina on or next to them, can also shield the patina from wear while creating contrast and depth.

If they want alternatives to liver of sulfur, jewelers can use proprietary compounds; McCreight notes. For example, Rio Grande in Albuquerque, New Mexico, produces a solution called Black Max Oxidizer, a mixture of tellurium and hydrochloric acid that is similar to a photography darkroom solution. “The advantage of something like Black Max is it gets the [silver] instantly black without a series of color changes,” McCreight says. Such compounds, he adds, offer speed and, often, greater stability, but they are usually more expensive than liver of sulfur and more caustic.

Copper Combos
For copper, artists have a range of alternatives through which they can achieve patinas. For example, Lynn says he makes his own copper sulfate and sodium chloride mixture that yields “a really good blue-green, and you don’t have to heat the metal. I paint it right on the surface.” He also notes that “sometimes just torching copper can reveal very deep blood reds.”

The Japanese in particular have highly prized the use of patinas on copper and its alloys. “No other people have used metal as expressively as the Japanese,” writes Robert Yon Neumann in his book The Design and Creation of Jewelry. “During the 450 years of isolation before the mid-nineteenth century, Japan was able to support [thousands of] metal craftsmen… Most were specialists in sword decoration… Metal was used as a color medium, and many subtle combinations of alloys were developed to extend the palette of the metalworker… Patinas added even greater range to the basic metal colors.”

A basic Japanese alloy that is often patinated is shibuichi. Translated, this word means “three to one” and refers to the basic mixture that consists of 75 parts of copper to 25 parts of silver. Other popular alloys are sambo-gin, or two-to-one copper and silver, and shakudo, which consists of about 96 percent copper and 4 percent gold.

Haga uses all three of these copper alloys in her work. She’s been studying Japanese alloys since 1986, and creates earrings, pendants, brooches, and bracelets that combine the simplicity of Japanese aesthetics and traditional materials with western techniques. Her pieces are known for their texture and patinas. They have a rugged, ancient quality that’s earthy, but with hints of contemporary styling.

“I love the wide variety of colors you can achieve with the degree of variations in the ratios found in these alloys,” she explains. “The beauty of these alloys is that they patina wonderfully. You can get lovely soft greens and grays, for example, with shibuichi. I’ve been able to get turquoise as well, which I think is because I first reticulate the metal [i.e., heat treats the alloy so that it wrinkles in unusual forms], which exposes more of the copper. I also get more variety of shading because the patinas are on top of and in the crevasses of the reticulation.”

In her work with shibuichi, Haga often uses a variation of the Japanese copper-sulfate mixture rokusho. Haga actually has a recipe to make it at home-but doesn’t, since some of the ingredients aren’t easy to come by. They include urine from a copper-reactive person, distilled pure water, grated daikon (a Japanese radish), plum vinegar, and cupric sulfate.

“That’s the basics, according to a book I have,” the artist says, noting that the shibuichi is immersed in a boiling solution of these ingredients. “Finding plum vinegar is hard enough, but who wants to track down the urine of a copper-reactive person?”

Instead, she uses a non-sudsy ammonia and vinegar, with a dash of salt, in a 50/50 solution. She says that different vinegar types (e.g. red wine, white, or apple) create variations in the shades achieved.

“If I’m using a reticulated piece, I put it in a pickling solution to clean it and then dry it well. I paint the piece with the ammonia solution again and then suspend it over some straight ammonia in an enclosed jar, which I cover with plastic and place near a heat lamp. The lamp offers a slower, more controlled way for the patination process to happen and I can stop it when I want.”

For shakudo-which Haga says is more expensive than shibuichi and harder to clean for patination because of its high copper content-proprietary solutions such as Multi-etch and Baldwin’s Patina (from Reactive Metals in Clarkdale, Arizona), used in combination to clean and then patinate the metal, work well to achieve a purple-black color. “Much easier than how the Japanese did it,” says Haga. “First they immersed the object in boiling lye prepared by smoldering wood ashes. Then they polished it with a charcoal powder and immersed it in plum vinegar containing salt. They washed it with weak lye, placed it in a tub of water to remove any traces of alkali, and immersed it again in a boiled solution of cupric sulfate, water, and verdigris [a greenish crystalline substance that forms on copper-bearing metals] until the purple-black patina was achieved.”

Photo Finish

Webb is another fan of Japanese aesthetics. She photoetches Japanese or African patterns on geometric pins and earrings of copper-clad fine silver-copper that’s been laminated over silver. (Photoetching is the process whereby photographs and other images are etched into the surface of a variety of metals by using special resists-acid-resistant chemical films-that are also light sensitive.)

Through this technique, Webb creates a pattern on the copper side of the laminate, then oxidizes the copper to create black or red patinas. “The patinas bring a textural quality to the surface and also draw attention to the relationship of the pattern to the form,” she explains.

To get the black patina, Webb evens out the finish of her photoetched piece on a satin-finishing wheel. To further normalize the surface, she bead-blasts it and then heats it in a kiln-just for a few minutes at about annealing temperatures (around 1,200°F) to eliminate as much of the copper from the silver as possible. When the piece is removed, its surface is a flat white color. She brass-brushes it and soaks it in silver cleaner, rinses it in water, then immerses it several times in cold liver of sulfur to achieve the black color she seeks.

“The silver part remains untouched because I remove enough copper by heating it in the kiln first,” Webb says. “I also think that because the liver of sulfur is cold, it does not affect the silver.” Upon achieving the desired color, she seals her work with a spray lacquer.

According to Webb, the process for a red patina is the most tedious. “I heat the piece in a kiln at below annealing temperatures to the point where all the copper turns black, [for] as long as it takes for the oxide to not flake off. Then I coat it with a paste flux [to pull oxygen out of the metal] and put it back in the kiln. After I pull the piece out, I let it cool to reveal the red color. Then I boil the flux off and seal it with lacquer.” The process can at times take her up to an hour.

The finished product can belie the time and effort Webb puts into her pieces. For that reason, she will often add gold and gemstones (such as white sapphire, pink tourmaline, iolite, lapis, citrine, and garnet) to enhance the perceived value of her work. However, like the other artists, Webb finds the true value of a patinated piece of jewelry is its ability to surprise: Just as a scar can make the human body more interesting, so too can patinated colors increase fascination with a piece of jewelry.

They can also impart a sense of history. You could say patinas go back to the time when the molten core of the earth cooled to form land masses. Undoubtedly, the exposed copper in the crust took on wonderful colors, particularly in the sulfurous atmosphere of the early days. And in a way, today’s artists are finding through patinas a way of extending that legacy, as well as conveying a sense of history.

“It’s the time element that fascinates me,” McCreight says. “Take two pennies–0ne that is shiny and new, the other old and walnut brown in color. I much prefer the used penny. It has a softer hue and a grounded quality that evokes the human touch. It went from shiny to deep brown by interaction with people. There’s history of use contained in that patina.”

AJM, June 2000 | 800-759-9997 | (fax) 800-616-9997