Reflections on Coatings, Textures and Color

by Mark Robins | May 1, 2019 12:00 am

Metal has a major impact on building lighting and reflection

By Mark Robins

Ppg May19 2 — The Emma and Georgina Bloomberg Center at Cornell Tech, New York City, features rainscreen panels finished with color-shifting PPG DURANAR VARI-COOL coatings in combination with A. Zahner Co.’s Louvered ZIRA system.

PHOTO: MATTHEW CARBONE, COURTESY OF PPG INDUSTRIES INC.

Metal panels present large, flat surfaces that can have a major impact on lighting and reflection. Metal by nature is a reflective material. For raw metal with a clear-coat only, the lightning and reflection will be quite high, and in some cases, will respond like a mirror depending on the finish of the metal (mirror, brushed, spangles, etc.). “Metal panels are highly constructible and also capable of expressing forms and movements that may be difficult for other materials to achieve,” says Souliyahn Keobounpheng, virtual design and construction team leader at MG McGrath, Maplewood, Minn. “Augmentations to this already extremely malleable material, by advancements in coatings, paints, textures, colors and finishes give architects a wide and versatile vocabulary to convey their art and develop compelling design narratives.”

Centria May19 1 — Color differentiates the OMNI Outpatient Surgery Center, Utica, N.Y. The facility’s exterior’s iridescent metal coating system changes color with varying angles of light, effectively shifting from one color to another as light reaches it.

PHOTO COURTESY OF CENTRIA

COATINGS AND PAINT

Various coatings can affect a building’s mood. Having a dramatic effect on a building’s overall aesthetic, coatings work in tandem with both natural and artificial lighting. Ilja Aljoskin, project manager, MG McGrath[1], Maplewood, Minn., explains that highly glossy and metallic paints can add dimensionality and reflectiveness. “Matte powder coat finish can add depth, weight and subtlety and a pearlescent finish can create striking visual effects not evident in flat paint. Matte and glossy placed together can create dramatic effects.”

Sources at Beckers Group[2], Berlin, Germany, explain that a coating and paint system chosen for a building will have a specific influence depending on the system, but only on the long term. Beckers Group sources contend that the color might degrade more depending on the type of resin or system. Then, color reflections can change; a bright orange might become a pale orange with time under light exposure and gloss might decrease as well. In this case, the thickness applied will impact mostly corrosion resistance (although there is still some erosion due to UV, so the thicker the longer).

Ask an Architect

Finish coatings often drive a material’s longevity, and express building sheen. Texture offers a remarkable range of building effects, from subtle definition to deep, shadow casting relief. Even more interesting is the combination of texture scale to generate character from a distance and at close range. A building’s emotion often comes most clearly from its color: intensity, playfulness, calmness and myriad others derive their immediacy from hue. The inherent lightweight and formability of metal imbue the material with a unique set of surfacing characteristics, which are then bolstered further by the color and sheen of the face to embolden or subdue its expression. Incident variable color coating is one of the most unique products I’ve encountered, as its dynamic expression encourages discovery by the viewer.
Colin Drake, AIA, LEED AP, principal, JRA Architects Inc[3]., Louisville, Ky.

Taking on Textures

Texture can sometimes help to reduce specular reflection and glare through light scattering, as well as have an impact on reducing gloss.
David Story, manager of color science, coil and extrusion building products, PPG Industries Inc., Pittsburgh

Striated or embossed textures and the use of curved profiles create dramatic wall relief thanks to the play of light and shadow on the building’s surface.
Chris Klein, coatings manager, CENTRIA, Moon Township, Pa.

Textures will have a direct impact on the spreading between diffuse reflection (the color of the object due to pigmentation) and specular reflection (color of the ambient light).
Beckers Group sources, Berlin, Germany

Embossing or applied textures would make the finish duller than a smooth panel and therefore would minimize reflection.
Lexi Edwards, marketing analyst, MBCI, Houston

Zahner May19 1 — The Contemporary Jewish Museum in San Francisco has a blue steel-clad Yud that has a jewel-like appearance that constantly changes depending on the light, sky and angle. It could appear like a gleaming mirrored dance floor, other times fairly uniform in various shades of blue, or nearly pitch black.

PHOTO: BRUCE DAMONTE, COURTESY OF A. ZAHNER CO.

Beckers Group sources suggest considering the differences between:

• A solid paint (same aspect whatever the angle of observation, and whatever the light ambiance)

• A metallic paint (which can sparkle under sunshine weather)

• An interference paint (with Mica or other pearlescent pigments), where the color (and so the reflection) changes depending on the angle of observation

Lexi Edwards, marketing analyst, MBCI[4], Houston, believes that architecturally, more metallic paints are being used today, and that historically, metal panels were white, tan or Galvalume. “The current trend has expanded to a wider color palette, including mica fluoropolymer. These metallic coatings give depth to the color, adding sheen and sparkle. In fact, there are actually metal flecks in the paint. Metal oxide-coated mica pigments offer up the metallic look and add to the durability.”

PVDF coating systems with the addition of either a gold or silver metallic flake offer an exceptionally luminous color effect that sparkles in the light. “This effect can be magnified with the use of directional artificial lighting,” says Chris Klein, coatings manager, CENTRIA[5], Moon Township, Pa. “While many coatings add or enhance the reflective value of exterior panels, a low-sheen textured PVDF coating serves as an excellent compliment to more reflective coatings with matte contrast, especially in situations where high reflectivity of gloss are not desired.”

Mbci May19 1 — MBCI’s FW-120 panel in Signature 300 Silver Metallic paint aid the exterior aesthetics of the Vasa Fitness facility, Lehi, Utah.
Photo COURTESY OF MBCI

Mc Grath May19 2 — Expected to open in Summer 2019, the U.S. Olympic Museum in Colorado Springs, Colo., has 3-D, diamond-shaped panels, fabricated from clear anodized aluminum in a satin finish that reflects the graceful movements of athlete’s muscles, bones and agility.
PHOTO COURTESY OF MG MCGRATH

The Basis Through Which We Perceive

Light is the basis through which we perceive. Skillful manipulation or orchestration of light is the essence through which we either identify or alter the perception of space and objects. I believe strongly in using materials in their natural state. It is both more ecologically friendly and produces finishes that are particular to their location. For instance, copper in dry climates ages differently than in wet and dry climates, producing projects that are reflective of their respected local conditions. Hence, in my work, applied coatings are of lesser impact. Instead, I rely largely on the use of natural light and metal in their natural state to create dramatic affects. Subtle, dramatic, and ever changing, natural light creates immediacy—a nuanced presence only found in that specific location. Metal, due to its inherent reflective properties, is an incredibly facile material with which to manipulate a building’s perception. Specifically, the specular nature of the material significantly alters the light that is reflected back to the human eye, changing the perceived color and depth.

Arnold Swanborn, AIA, LEED AP, design director/principal, CO Architects[6], Los Angeles

COLOR REFLECTION

Color choice is one of the most important design decisions because it affects building lighting. The manner in which light is reflected—or absorbed—establishes both the depth and the profile of the building. Reflection is mainly a byproduct of color choice, special effects, degree of gloss, and to a lesser extent, the presence of texture. Similarly, all materials will absorb and reflect varying amounts of solar radiation based primarily on their color and reflectance.

Edwards says the way to measure that variation is based on ASTM test standards E903 and C1549. “These tests are used to determine the solar reflectance (SR) of materials, which is expressed as the fraction of solar energy that is reflected on a scale of 0 to 1. Black paint, for example, has an SR of 0 and bright white titanium paint has an SR of 1 (highest reflectance). Darker colors are going to absorb more light than lighter colors therefore casting less reflection of light off the building.”

Color contributes to both absorbance and light reflectance in the ultraviolet (UV), visible and near-infrared regions of the electromagnetic light spectrum. The larger the surface area is, (whether for interior or exterior portions of the building), the greater impact of colored coatings. “For exterior surfaces such as wall systems and roofing, PPG DURANAR ULTRA-COOL and PPG Duranar VARI-COOL coatings employ special pigments engineered to absorb light in the visible spectrum (where we see color used for visual aesthetics), while at the same time reflecting heat-containing light in the (invisible) near-infrared spectrum,” says David Story, manager of color science, coil and extrusion building products, PPG Industries Inc.[7], Pittsburgh. “This helps architects and building owners to reduce the amount of absorbed heat (and air-conditioning usage) coming into the building that contributes to the Heat Island Effect, which is so prevalent in major metropolitan cities.”

Ppg May19 1 — Passive House at Cornell Tech, New York City, one of the tallest Passive House buildings in the world, features two PPG DURANAR MXL coatings colors. “Zenon Atoms,” developed for the building skin, transitions from silver to a gold or champagne color in direct sunlight. Kappa 4.1, selected for the building’s deep window wells, shows a plain bronze shade with very little sparkle but has a 3-D rainbow sparkle when exposed to sunlight.

PHOTO: JONATHAN MOREFIELD, COURTESY OF PPG INDUSTRIES INC.

“Colors can be used to create a calming sensation in certain circumstances,” says Gary Davis, director of marketing, A. Zahner Co[8]., Kansas City, Mo. “They can also be used to stimulate the brain of the viewer. Colors change throughout the day and the ambiance of natural color shift should be uplifting to those who drive by/walk by or work in a noble piece of architect.” Keobounpheng believes colors can convey a sense of playfulness and openness, suggest an invitation to enter and can even be, “imbued with the sensibility of site and program.”

The use of iridescent colors and coating systems can change the appearance of the metal panel surface— and the building exterior—depending on the viewing angle or the direction of reflecting sunlight. “The continuous iridescent color gradient creates depth and adds distinguished aesthetic value, all with the exceptional performance expected from PVDF coatings,” Klein says.

Co Architects May19 2 — The University of Arizona Health Sciences Education Building (HSEB) and Biomedical Sciences Partnership Building (BPSB), Phoenix, show how natural light and metal can aid a project. The envelope’s copper panels utilize Arizona’s abundant sunlight to produce a pattern of light and shadow, and also act as a conductor of heat.
PHOTO: BILL TIMMERMAN PHOTOGRAPHY, COURTESY OF CO ARCHITECTS

Endnotes:

MG McGrath: http://www.mgmcgrath.com
Beckers Group: http://www.beckers-group.com
JRA Architects Inc: http://www.jrarchitects.com
MBCI: http://www.mbci.com
CENTRIA: http://www.centria.com
CO Architects: http://coarchitects.com
PPG Industries Inc.: http://www.ppg.com
A. Zahner Co: http://www.azahner.com

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