Wendy Davis: Helping manufacturers bring energy-saving lighting to consumers

Wendy Davis established and leads the Vision Science Laboratory at NIST.
Wendy Davis established and leads the Vision Science Laboratory at NIST.
The Partnership for Public Service
Monday, March 14, 2011; 7:33 PM

Nearly 2,000 tiny lights shine from the ceiling of Wendy Davis' Maryland laboratory, allowing the "vision scientist" to come up with measurements for energy saving lighting for homes and businesses.

The Vision Science laboratory that Davis established and leads at the National Institute of Standards and Technology (NIST) -- the only one of its kind in the world -- runs experiments with LEDs or light-emitting diodes, now used in traffic signals, nightlights and backpackers' headlamps.

LEDs, a type of solid-state lighting, last much longer than other lights and many people are interested in expanding the market for their use. Nearly 12 percent of the electricity consumed in the United States goes to powering lights in people's homes and 25 percent is used in commercial buildings, according to the Department of Energy.

"LEDs have the potential to be much more efficient than the light sources we have now," Davis said.

But scientists have realized that the usual methods for assessing the quality of the lighting were not working. Davis and her colleagues turned to the task of developing metrics to guide manufacturers, who need to make sure their lights make objects appear natural. Consumers won't buy lights that make interiors look unappealing and manufacturers don't want to make the mistake of producing such products.

Davis cited the debut of compact fluorescent lights, whose sometimes cold appearance received an even colder consumer reception. She hopes her work will help manufacturers avoid a similar reaction to LEDs. "Everyone's excited to see this technology succeed, but if we can't measure the properties, businesses will inadvertently create bad products," she said.

Since the lab opened in 2009, Davis and her colleagues have developed a metric for a new color-rendering standard with the potential to replace a decades-old one. It's now working its way through the international standards process. Essentially, Davis said, predicting how a light source will perform "is a bunch of math that will give a number on how a light source would allow us to see the color of objects."

In her lab, scientists create lighting conditions to evaluate how subjects register colors, according to Yoshi Ohno, a group leader in the Optical Technology Division, who oversees Davis' project.

"Wendy is the key person on color quality experiments and she's doing a great job in how she has designed vision experiments," said Ohno.

Subjects enter a homey environment outfitted with couches, tables and plates of food. Under certain lighting conditions, a strawberry that looks beautifully red in the sun might appear brown. In one experiment, Davis asks people to put in order several sheets of red paper, all of slightly different shades, based on their similarity to each succeeding one. Depending on the frequency and magnitude of errors, Davis assesses how different light sources allow people to discriminate colors.

"If we ever want to improve the way we measure lighting, we have to start with visual perception," Davis said.

NIST is working on another project with the Academy of Motion Picture Arts and Sciences, the Oscar people. Budget-conscious movie producers would like to be able to switch from energy gobbling tungsten lights to long-life LEDs for illuminating movie sets more efficiently during long days of filming. But the images that appear through a camera are processed differently from what the eye sees.

"You can't just take the work we're doing and translate it," Davis said.

By reducing costs for the motion-picture industry, NIST will help increase the competitiveness of a strong, U.S.-based business, Davis pointed out. But, she added, NIST has to balance those aims with its core work of developing international standards, which are better for everyone.

Davis, who majored in psychology and physiology as an undergraduate, knows that interacting with human subjects can be a tricky business, but she loves her work.

"It's a great intersection between just being a scientist and being in a lab and following your bliss in terms of intellectual curiosity, and being connected to the real world and having an impact," Davis said. "And maybe, just maybe, helping people."

This article was jointly prepared by the Partnership for Public Service, a group seeking to enhance the performance of the federal government, and washingtonpost.com . Go to http://www.washingtonpost.com/wp-srv/politics/fedpage/players/ to read about more federal workers who are making a difference.

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