Copper Guide Part 4: Star Blue™ — Zahner’s Blue-Green Copper Patina

This is the fourth and final installation of our series on copper and copper alloys. Read about the history of copper in part 1, the finishes and patinas of copper in part 2, and the characteristics of Dirty Penny™ in part 3.

Star Blue™ copper is a preweathered surface developed and offered by A. Zahner Company. This blue-green patina allows artists and architects to accomplish an aged copper look without the wait.

Deep green natural patinas, which used to take a decade or so to develop in more polluted conditions, will take a century or more in our modern world. Star Blue provides an answer.

Using a technique that speeds up the weathering process in a tightly controlled environment, the blue-green antiqued appearance is ready in a matter of weeks.

After a carefully rolled application of Star Blue, the patinated copper may be installed on wall paneling systems, roofing systems, and architectural accents, in addition to art and sculpture projects of any scale.

Creating Artificial Green Patinas

Star Blue and other artificial green patinas are decorative treatments to copper alloy surfaces, with their planned chemical reactions on the surface between the copper and chemical compound.

They mimic what occurs naturally when copper is exposed to the atmosphere but are produced in a concentrated and controlled environment.

Artists and architects working with green patinas can arrive at a desired color tone while dramatically accelerating the time of development.

When first installed, the patina will exhibit the color tone produced in the factory. But after a few months of exposure, the patina will develop a richer hue as it absorbs moisture from the air (as well as from carbon dioxide and other pollutants).

Skillful Verdigris, Colorful Benefits of Star Blue

Architectural copper panels are typically installed as raw or ‘red’ copper sheets. The color progresses from reflective pinks and reds to a matte brown. However, it will take decades before the metal patinates into the blues and greens so desired for architectural projects.

This installation of unpatinated copper can be seen at the de Young Museum in California, where Zahner manufactured and installed a panel system in 2003-2005.

Fast forward a decade, one can identify subtle signs of green along the panel seams, but the overall tone reflects a deep brown color reminiscent of burnt umber. It’s projected to be another few decades before the surface takes on a green hue.

Artificial green patinas are a popular choice for immediate blue-green color effect. Such patinas are achieved through a chemical process involving copper acetate called verdigris.

The issue with this verdigris is that it can leave the material in a soluble state if attempted without expert precision.

The Zahner standard offers a level of mastery when taking verdigris to an insoluble state. The technicians initiating this process ensure that the patina properly fuses to the surface. This is Star Blue: a chemically stable patina surface produced safely using rapid-patination.

Star Blue In Application

Both artistic vision and scientific understanding are required in the Star Blue patination process. Zahner trains experts in both areas.

This dual approach creates a high-performance, artful patinated panel that stands apart from the uniform, less inspired machine-produced patinas.

This contemporary and unconventional appeal makes Star Blue popular among forward-looking designers and architects, as well as their institutional clients. It is no surprise that the following examples include a university, a library, an art museum, and an embassy.

Two hundred and ninety sheets of Star Blue patinated copper were fabricated by Zahner for The Brandywine Hundred Library in New Castle.

Designed to enhance modern interconnectivity, a unique and rustic copper patina canopy greets guests at this 40,000-gross-square-foot library.

The new Margaret M. Walter Wing of the Columbus Museum of Art welcomes the visitors and residents of Columbus, Ohio, to global exhibitions hosted there annually.

The structure is a contemporary work of architecture that links the museum’s rich history with visions of an expansive future.

Related Project

Columbus Museum of Art

In 2013, the Columbus Museum of Art's Board of Trustees unanimously voted in favor of beginning construction on a new expansion project which would enable the Museum to bring global exhibitions to the residents of Columbus, Ohio. The museum reached out to DesignGroup principal Michael Bongiorno whose design team, including Keoni Fleming, Annie Neumer, and Joseph Mayer, developed a strategy for the museum's expansion. The expansion's centerpiece, the Margaret M. Walter Wing, adds 50,000 square feet to the total square footage of the Museum's available gallery space, and is expected to reach a LEED Silver certification.

This sentiment is mirrored as modern architectural touches interplay with a cohesive surface of antiqued copper: A custom variation of Star Blue.

More Examples of Star Blue in Application:

• 174 North Eleventh in Brooklyn, New York
• SMU Collins Executive Center in Dallas, Texas
• SUNY Campus Commons at New Paltz

Star Blue for the Arts

Artistic expression can be enhanced by the colorful tones of Star Blue on smaller surfaces. Zahner has spearheaded several sculptural projects that utilize this patina.

The Oculus Sculpture, by artist Reilly Hoffman, was produced in conjunction with the Kansas City Art Institute’s Biennial Auction for Student Scholarships.

Zahner manufactured the base form in aluminum, while Hoffman crafted the copper and steel with his signature torch-carving techniques.

The large, curved sculpture is finished with Star Blue patina on hammered copper to create an iridescent blue-green color across the back and inner sections.

While an impressive object without this added pop, the Star Blue application adds eye-catching detail and brightening contrast against the sealed red copper and steel.

Heartland Harvest, a 60-foot tall sculpture finished with Star Blue, was installed on the Kansas City Board of Trade building in 1999.

Designed by Joel Marquardt of Gastinger Walker Harden Architects, a miniature maquette was created and shared with Zahner engineers.

The team designed a custom “on-off” press to replicate the models exact indentations in Star Blue patinated copper.

Resilience To Atmospheric Elements

Star Blue patinas on rooftops and facades worldwide can perform well in all environments. Exposure to moisture, oxygen, and carbon dioxide enrich these surfaces very slowly over time, similar to naturally forming patinas.

Roof surfaces are especially subject to rain, hailstorms, ultraviolet radiation, and particles of pollutants coming out of the atmosphere. These tend to remain on the surface for a prolonged period.

As moisture from condensation forms, these pollutants can combine with the copper patina with some darkening effects.