More than 40 years ago, when A Chorus Line first came to Broadway, it brought with it a revolutionary approach to lighting design. The show used a computer, affectionately nicknamed Sam, to program and run the display each night.

And because it was automatic, the lighting was far more dynamic than any manually-run Broadway show had been before. Without Sam, the show’s producers said, half of the light movements would have been cut—simply because humans couldn’t change the lights so quickly. “This is a quantum jump,” Gershen Shevett, who ran the lights at the Shubert Theater, told The New York Times in 1975, “from the Bronze Age to a moon shot.”

People noticed the leap. Among the nine Tony awards that A Chorus Line eventually won, one was the accolade for Best Lighting Design. Broadway shows have been building on Sam’s success ever since.

But what happens to those light shows when a production finishes its run?

That’s been a question tugging at lighting designers and theater historians for some time now. Machine-programmed lighting isn’t documented the way the lighting schemes from earlier theater productions are sketched or otherwise described in stage records. “How can we make sure that all of that information is preserved in the same way as the lighting design for something like Oklahoma on Broadway [in 1943] or even something like The Black Crook in 1866?” said Doug Reside, the theater curator for the New York Public Library.

That’s the goal of a new project, funded in part by the National Endowment for the Humanities, to figure out how to preserve historic theater lighting design. And not only that: Reside and his colleagues also want to test methods for visualizing those designs, including 3-D modeling and immersive displays of historic lighting design that could be experienced in virtual reality.

“Theater is an art form that’s really hard to pin down. It’s not like literature or poetry where you have the thing on the page. All we really have are the traces of the historical event that took place in a particular theater, in a particular run,” Reside told me. “Lighting design is the thing that’s hardest to understand from historical documents. If you look at a set design, you get a sense of what that set looks like ... and the same is true for a costume bible. But with lighting, the photographs certainly don’t capture the dynamic lighting—and they also frequently don’t capture what the lighting looked like.”

To suss out the best way to such an ephemeral art form, archivists have looked to the preservation of other artifacts from the digital age, such as video games and early computer programs. “It’s not enough just to have the source code for something like Pac-Man,” Reside said. “You want to also be able to play Pac-Man.”

Pac-Man is a particularly good example. In 2012, when the Museum of Modern Art in New York acquired Pac-Man and 13 other video games, design curators wrestled with the exact challenge Reside describes. “It’s very different from when you acquire a poster or a chair, when what you see is what you get, and what you acquire is what you put in the gallery,” the curatorial assistant Kate Carmody told me at the time. “What exactly are you collecting? Are you collecting the software? Because then you need the hardware to collect it. Are you collecting the interaction? Because maybe a film of someone playing is the best way. Do you display the code?”

Digital archivists everywhere are still trying to establish standards for how to handle computer-age resources. The Internet Archive, a leader in digital archiving, has a web-based library of arcade games from the 1970s, for instance. Digital lighting design poses an especially difficult challenge because historians are interested not just in the design itself, but also in the effect of that design as theatergoers experienced it. “So much lighting design today is completely digitally created,” Reside said. “The aim of this project is to preserve not just the data but what did the data mean.”