Architectural Lighting: The Case for More Research

When one talks about architectural lighting, it’s more often than not about the design aspect of the profession or the projects of leading firms. What often goes overlooked is the driver behind lighting advancements: research.

Research generally falls into one of two paths: fundamental and applied. In the field of lighting, fundamental research focuses on the science of light; much of the significant lighting advancements of the early 19th century were made in electricity, photometry, and the development of new lamp sources. Meanwhile, applied research covers practical matters such as performance, daylighting, and sustainability.

Large and Larger Challenges
The introduction of LEDs and advancements in solid-state lighting (SSL) over the past 15 years have led to the re-examination of fundamental technological issues—color, flicker, dimming, brightness, glare, optics, and controls—as well as to challenges related to applications, such as lighting metrics and new performance criteria to consider in the illumination of spaces. “Everybody’s a bit concerned about having only one light source to choose from,” says Mariana Figueiro, director of the Lighting Research Center (LRC) and architecture professor at Rensselaer Polytechnic Institute in Troy, N.Y. “There is no R&D on any other light source. Everything is LEDs. Yes, it is energy efficient, but will people accept and like it? There are many human factors associated with the use of LEDs that we still do not know.”

Other lighting experts share Figueiro’s concerns. Robert Davis, senior staff lighting engineer at the Pacific Northwest National Laboratory (PNNL) in Portland, Ore., cautions that researchers have to make room for both new and established areas of investigation. He points to the “explosion of interest in the so-called ‘nonvisual’ aspects of lighting, precipitated in large part by the discovery of the ipRGC photoreceptors at the turn of the century.” (IpRGC photoreceptors are critical to synchronizing our circadian rhythm to light; the other photoreceptors are rods and cones.) But by focusing on the “sexy new thing,” Davis continues, “we forget about long-standing needs for lighting research like better color metrics, better glare metrics, better quality metrics, and a better understanding about how light affects people cognitively and emotionally, through both visual and nonvisual means.”

Even with newfound research areas attracting more interest, the lighting design profession remains small—and the research constituency within even smaller. It is “a community of thousands,” says Kevin Houser, professor of architectural engineering at Pennsylvania State University and editor-in-chief of Leukos, the journal of the New York–based nonprofit Illuminating Engineering Society (IES).

In the United States, the network that focuses on lighting-specific research comprises a core group of academic institutions, professional associations, and government entities: the IES, the LRC, the U.S. Department of Energy’s (DOE’s) Solid-State Lighting Program, and other DOE laboratories, such as the PNNL and the Lawrence Berkeley National Laboratory in Berkeley, Calif.

Globally, a number of academic institutions and research organizations—including the Commission Internationale de l’Eclairage (CIE) in Vienna, the École Polytechnique Fédérale de Lausanne in Switzerland, and the National Research Council of Canada in Ottawa—provide thought leadership and contribute significantly to the broad lighting research agenda.

Advancing the Agenda
In 2015, the IES established a Strategic Research Advisory Panel and outlined four research priorities that tie back to the society’s core tenet of discovery: to refine knowledge about lighting and visual processes; understand the impact of light exposure on human health; foster the integration of lighting into the holistic built environment; and demonstrate the value of quality lighting.

Similarly, in 2016, the CIE established a strategic research plan that named 10 topics ripe for investigation. These topics include glare, color quality, calibration sources and illuminants, and health-related and nonvisual effects of light (see “CIE Priority Research Topics,” below). Combined with the IES Strategic Research Advisory Panel’s aforementioned priorities, these 14 topics cover a swath of both fundamental and applied research areas. They also indirectly highlight another of major challenge facing the research community: funding.

Funding Matters
Perhaps surprisingly, the lighting industry, which includes product manufacturers, has not been a significant source of funding for research. “Industry is very interested and willing to provide support in many important ways,” Davis says, “but the reality of the costs for conducting high quality research today, combined with the reality of a low-profit-margin—some would say commodity—industry, means that funding must come from deeper pockets.”

In the United States, those deeper pockets belong mainly to the DOE. Specifically, the DOE Office of Science provides hundreds of grants across its 12 research and development program offices. The DOE’s SSL program, for example, awards SSL research and technology grants to fund upwards of 10 SSL and OLED (organic LED) research projects annually.

Figueiro and her team at the LRC have also found success in reaching out to the medical and scientific communities for funding, particularly in research areas that are generating a lot of interest: light and health, and the circadian cycle. “We’re always looking outward and looking at the user of light,” she says. Working with organizations such as the National Institutes of Health, the National Institute on Aging, and the National Science Foundation, the LRC has been able to advance a number of studies that examine “the impact of light on human health and well-being,” she notes.

Resources and Collaboration
One long-standing vehicle for disseminating the latest in lighting research is lighting journals, such as Lighting Research & Technology, in the United Kingdom, and the aforementioned Leukos. Lighting research discussions can “really explode,” Houser says, when one considers content from other peer-reviewed journals, such as Building and Environment, Energy and Buildings, Journal of Environmental Psychology, Optics Express, and Journal of Modern Optics. When conversation expands “into the physics and chemistry of light generation and the material science aspects of lighting,” Houser continues, “then, it’s much, much bigger.”

Since 2012, Leukos has experienced an increase in article submissions. Factors contributing to its growth include its partnership with global publisher Taylor & Francis and its expanding online presence, where both IES members and the public can access content. Making the journal available to the entire lighting community and beyond has been a priority for Houser. This year, Leukos will publish a special issue on lighting research methods that will be made available online for free thanks to a collaborative initiative between the IES and the CIE.

Although architects, and even some lighting designers, might not recognize how fundamental and applied research directly affects their everyday work, it remains as critical as ever. A research agenda open to new avenues of exploration and to areas that span multiple disciplines can serve as a strong backbone to generate both funding and widespread, sustained interest.