When it became clear that the Gay Head Lighthouse had to be moved away from the clay cliffs of Aquinnah to save it from toppling into the sea, it seemed like the most natural thing for Liz Witham and Ken Wentworth to make a documentary film about it.

The husband and wife filmmaking team began shooting Keepers of the Light at the inception of the project, long before the lighthouse was actually moved, and followed the progress until it was settled on its new location.

The filmmakers were researching state and federal historical archives when they found the history of the Gay Head Light in surprising detail. — Ray Ewing

But the film covers far more than the move. It is really a look at Aquinnah’s long maritime history, through the lens of the lighthouse.

“I grew up in the town of Aquinnah,” said Ms. Witham. “I know how important the lighthouse was to the town, and to the Island. I felt this is something that should be documented. I knew it was interesting, but I didn’t know how interesting it would be.”

Both filmmakers are versed in all the technical aspects of making films, and share the nuts and bolts work of putting together a documentary.

“We have our strengths, but in this project Liz is the director,” Mr. Wentworth said. “We try to distinguish who is going to be the lead on something, or it can get a little confusing.”

Gay Head Light in 1887. New documentary looks back at lighthouse's long history.

“We share an aesthetic,” said Ms. Witham. “When we look back at the footage later, it’s really hard to identify who was shooting what. We share a similar style.”

Their research journey took them to state and federal historical archives, where they found the history of the light preserved in surprising detail.

“It was all there waiting for us, the real deal,” Mr. Wentworth said. “Letters, the original signatures and papers. They have every keeper’s log there.”

The story of the lighthouse begins in the 1790s, when the lighthouse was erected by the federal government. Sitting at the base of the lighthouse for an interview this week, the couple marveled at the many branches of history that meet at the location.

“This spot is really an amazing spot,” Mr. Wentworth said. “A lot of things come together. For American history, the first lighthouses that were created was the first act of Congress, and the land here that was taken was one of the first uses of eminent domain by the United States government.”

The film is also the story of the rich maritime history of the Wampanoag Tribe. For many years, the lighthouse keeper was the only white man who lived in the town.

Free outdoor screening scheduled for July 19 in Aquinnah.

“All of Aquinnah was held in common by the Wampanoag people, except for this two acres here for the lighthouse,” said Ms. Witham. “It was kind of an interesting dynamic. That comes out in the film.”

“For the Wampanoag here this lighthouse has always been really important,” Mr. Wentworth said. “It drove tourism here, they had the steamboat landing, it brought people up. The first Native American lighthouse keeper in America was Charles Vanderhoop. They were very proud of that.”

The filmmakers found an enthusiastic spirit of participation when they interviewed local residents whose ancestors were part of the history of the lighthouse. Ms. Witham said it was a bit tricky to interview her friends and neighbors sometimes, but in the end, her familiarity with them proved an asset.

“One of the nice things about interviewing people you know is there is a lot of context and back story and history about each one of these people that are in the film, that we understand well,” she said. “I feel like we were able to capture the stories in depth. It was a fun film to make.”

The premier of Keepers of the Light should be a fun affair, too. A free showing of the film is set for an outdoor screen on the Aquinnah Circle on July 19. Following that, the film will headline the Woods Hole Film Festival, and then be part of a special presentation at the National Lighthouse Museum on Staten Island. The film will also screen at the Martha’s Vineyard Film Center on Tuesday, August 7 — National Lighthouse Day.

In October, the documentary will be aired on WGBH TV, the public television station in Boston.

“This is a very interesting, fun film for people to learn more about the Vineyard, and learn more about the maritime history of this region,” Ms. Witham said. “It’s going to be a lot of fun to recognize familiar faces, and see how many people were part of this history. We’re so lucky to be in this place where there are generations of people who carry these stories. It’s all here still. That’s really special.”