When actress Helen Hedman wrapped up a holiday run of the Ken Ludwig adaptation of “Murder on the Orient Express” at the Everyman Theatre in Baltimore, she turned her attention to a very different dramatic pursuit, the recording of German writer Uwe Johnson’s masterwork, “Anniversaries: From a Year in the Life of Gesine Cresspahl.”

Working with narrator Laura Giannarelli — who had interrupted her reading of the two-volume, 1,700-page novel to direct the George Bernard Shaw comedy “Candida” at the Washington Stage Guild — Hedman used her theater expertise to help shape their telling of the sprawling story, which toggles between 1960s New York City and 1930s Germany.

Hedman and Giannarelli are among the well-known Washington actors working day jobs producing “talking books” for the Library of Congress’s National Library Service for the Blind and Print Disabled. Long before the audiobook craze took hold, a crew of local theater artists — now including Dawn Ursula, Michael Kramer, Michael Russotto and Nora Achrati — started recording audio versions of popular books and classics in the basement studios on Taylor Street NW.

“It’s theater of the mind,” said John Lescault, a narrator for more than two decades, who appears next month in Mosaic Theater Company’s “Inherit the Windbag.” “It’s very intimate. You’re right there inside someone’s head.”

The NLS’s first talking books were made in 1934 on records, and included civic offerings such as the Declaration of Independence, the U.S. Constitution and Lincoln’s Gettysburg Address, as well as Shakespeare’s “As You Like It” and P.G. Wodehouse’s “Very Good, Jeeves.” Technology has changed — the studio is all digital now — but its central mission has not.

With all forms of audio storytelling soaring in popularity, the NLS has shifted its focus to take on more complex books like “Anniversaries” — described as a German “Ulysses” and recently translated into English by Damion Searls — while leaving many best sellers, thrillers and other genres to its commercial partners.

The job appeals to Washington’s professional actors for both practical and emotional reasons. It offers a flexible schedule, a big plus in the unpredictable world of rehearsals and performances, and a regular paycheck to buffer the financial uncertainties of theater.

“There is no tour of duty,” Giannarelli said. “You don’t have to invent a dead grandmother for an audition.”

It is not an easy job to get, in part because of low turnover. Candidates must submit a five-minute demo, and those with potential are brought in for an audition, said studio director Celeste Lawson, who does the hiring. A former actress herself, Lawson has worked for the NLS since 1991. She has a staff of 22 and no current openings.

Unlike other side hustles such as driving for Uber or waiting tables, the three tasks in the studio — narrating, producing and critiquing — are connected to their true profession.

“It’s a lovely day job to have and still be working on your craft,” said Ursula, who left this month for San Francisco, where she’s rehearsing “Toni Stone,” a co-production between A.C.T. and Arena Stage that runs March 5-29 in California before beginning a five-week run in the District on April 23. “The level of honesty and simplicity that happens behind the microphone in the booth has made me aware of how much I get away with on the stage and on camera.”

Not every performer can do narration, Lawson said. A narrator needs a pleasant, mid-register voice, she said, and the ability to embrace the intimate, relaxed nature of storytelling.

“A really good book narrator knows how to tell a story,” she said. “They don’t rush it, they give the time to absorb images or feel emotions. It’s hard to teach those things.”

The NLS was established by Congress in 1931 to provide reading materials for blind adults, including 22,000 books in Braille. The legislation has been updated several times to include music material and work geared for children and to expand eligibility to individuals with physical impairments that prevent the reading of standard print.

The service has roughly 550,000 users, representing all 50 states and some living abroad. Registration is free, but requires proof of need.

While the Washington studio is the flagship, the NLS also contracts with five others to produce about 4,000 books each year. There are about 143,000 talking books available, including 10,000 commercially produced titles, and about 65 percent are fiction.

A library committee selects the books to be adapted and added to the collection. The group considers a book’s popularity, user requests and its value to the collection, which covers a range of topics and age levels.

Lawson matches the books to the voices, interests and skill sets of her staff. “Having somebody read a book they’re not interested in can kill it,” she said.

Hedman has assisted in the production and quality control of NLS audiobooks for three decades, work that dovetails with her acting roles. “You get to have input into the telling of the story,” she said. “With new narrators it’s about being as encouraging as possible, helping them find their way to tell the story.”

“An actor should listen to other actors and learn from what you’re hearing. I know it seems basic, but sometimes you’re so concerned about your character and what you’re doing, you forget.”

Beyond the ability to listen, special skills can come into play. Lawson asked Giannarelli to narrate the epic “Anniversaries” because the book features German and French, languages Giannarelli knows. There’s also Czech, which has led Giannarelli to contact a member of the Czech Embassy for pronunciations.

Giannarelli is also one of the most prolific narrators, working an average of 30 hours a week in the studio. Since 1979 she has narrated more than 1,000 books, including the “Little House on the Prairie” series by Laura Ingalls Wilder and many novels by Joyce Carol Oates (a challenge, she said, because the writer “has only a nodding acquaintance with the period, so [narration requires] lots of long sentences, lots of breath control.”)

Some narrators have gained a following among users. Sherry Miller, a resident of Grand Blanc, Mich., has been an NLS patron for decades and estimates that she listens to about 10 books a month. She is a Giannarelli fan.

“She is very enjoyable to listen to,” Miller said. “The very good ones have great pronunciation and good expression and sometimes, like Laura, they will actually change their voices for different characters.”

In addition to financial support, the NLS studio provides a sense of community for the peripatetic actors.

“It’s one of the main things I miss if I’m away,” said Hedman, who will appear in “Big Love” at Round House Theater in May. “There are friendships forged in the recording studio, even with people I haven’t had the chance to do a show with.”