Fenella G. France views a scan of a copy of Thomas Jefferson's hand written draft of the Declaration of Independence on July 8, 2011. France is a finalist for the Samuel J. Heyman Service to America award. (Mark Gail/THE WASHINGTON POST)

Fenella France could see the faint trace of a cursive ‘t’ — a clue to the word deliberately smudged out and replaced by “citizens” in Thomas Jefferson’s original draft of the Declaration of Independence.

Perhaps Jefferson had written“patriots,” or even “residents,” France thought.

Then, using a modified version of spectral imaging technology developed for the military, France solved one of the greatest mysteries baffling researchers of the American Revolution: “Subjects.”

“His handwriting is usually so neat, and words are simply crossed out in other places,” France said. “But this was a very deliberate attempt to write over the word ‘subjects’ and cover it.”

France, 44, now a leading cultural heritage preservation scientist at the Library of Congress, was named one of four finalists for this year’s Samuel J. Heyman Service to America Science and Environmental Medal for her work in developing imaging techniques that won’t harm documents. Considered the federal worker’s Academy Awards, the Service to America medals are awarded annually by the nonprofit Partnership for Public Service.

“There’s quite a lot of detective work in this,” said France, who joined the Library of Congress staff in 2007. “I can find something, like the smudge, and say here’s what we’ve got, here’s some extra text, and we’ll collaborate with historians to see if it’s relevant.”

France, a soft-spoken New Zealand native who became a U.S. citizen last year, said she never cared much for history class. Her interests flitted from dance to fashion to textile science, when she found her calling as a preservation scientist.

She has worked to ensure that some of America’s most important historical documents and artifacts will remain intact for generations to come. And she has found secrets hidden within them.

That brownish 150-year-old stain on the Gettysburg Address? A thumbprint that may belong to Lincoln himself. And D.C. city planner Pierre Charles L’Enfant’s original design for the intersection of 16th and K a few blocks from the White House? Possibly a traffic circle. (“My Dan Brown moment,” she quips.)

France’s simple work attire — a white cotton T-shirt, Mulberry straight-cut pants, and loafers that allow her to spend 12-hour days on her feet poring over documents and scanned images — belies her obsession with fabrics. She designs most of her clothes and prefers styles reminiscent of Issey Miyake, the Japanese designer known for his geometric silhouettes and clean lines.

When working with the imaging technology, France wears her bright orange safety goggles — “They’re my Jackie O-slash-Bono glasses,” she says — to protect her eyes from the machine’s ultraviolet rays.

France scans documents through the spectrum of light, usually from UV through the visible into the infrared region. She then analyzes the scanned images using various combinations of light spectra, or wavelengths.

A document’s response to different wavelengths of lights based on the chemicals and elements in and on it can yield information such as different inks used at different times, for example.

The clutter of her office marks a stark contrast to the sterile environment of her imaging lab, where no pens are allowed anywhere near documents worth millions of dollars. An image of Abraham Lincoln with his two secretaries was taped onto her file cabinet.

Michael B. Toth, a friend and colleague of France since 2007, praised her efficiency and attention to detail when tackling projects.

“Her approach is a very quiet approach; she’s very diligent and makes sure she has all her ducks in order,” Toth said. “But she moves very quickly and gets a lot done.”

Toth added that France’s Kiwi background often colors their discussions, whether in the lab (she brings an international perspective to the table) or off work (she once compared a baseball game to cricket).

France, who is single, was born and raised in the Hawke’s Bay region of the North Island of New Zealand. She thought about being a veterinarian, until a friend told her New Zealand’s cattle would probably squash her.

Despite her petite frame, France carries herself tall, shoulders back and neck elongated, betraying her classical dance training of 20-some years. Surgery on both feet forced her to stop dancing and take up running and aerobics instead.

At the University of Otago in Dunedin, New Zealand, France completed her bachelor’s degree in applied sciences, a master’s and a PhD in textile science by 1995. She later received a master’s in business administration from Deakin University in Melbourne, Australia.

Her career in preservation science started when a New Zealand museum recruited her to develop a simple technique to determine which artifacts of the Maori, the indigenous Polynesian people of New Zealand, could be safely put on display.

France came to the United States in 1998 to work on the restoration of the U.S. flag that flew over Fort McHenry during the War of 1812 and inspired Francis Scott Key to write “The Star-Spangled Banner.” It’s at the National Museum of American History. She has since worked on several projects in the District and in New York, including Ellis Island artifacts and a 1507 Waldseemuller world map, which is known as the first map to use the name America.

In 2010, France became a U.S. citizen. Tears rolled down her face during the citizenship ceremony when images of America flashed before her: the American flag, the Declaration of Independence, Ellis Island.

“I felt bad for the poor lady next to me,” France recalled. “It was so emotional, I’ve been so privileged to have worked with so many historic American documents.”

Editor’s note: In the world of the federal workforce, GS means “general schedule,” the largest pay system for civil servants. We’ve borrowed the initials for our weekly series profiling metro area federal workers. Profile subjects have been pulled from a list of 34 employees from across the country nominated for the 2011 Samuel J. Heyman Service to America Medal awards. The “Sammies” — offered in nine categories — are the Academy Awards of the federal world ans sponsored by the nonprofit Partnership for Public Service.