The key to enjoying “Jazz on a Summer’s Day” may be in knowing that the movie is as interested in the second part of its title as the first.

Not exactly a concert film, “Summer’s Day” opens with impressionistic shots of shimmering water, presumably near the shore of Newport, R.I. That’s where the newly restored movie takes place, on a 1958 day when the Newport Jazz Festival and the America’s Cup yacht race were in full swing. Directors Bert Stern and Aram Avakian wander all over Newport in a way that could annoy jazz fans who come to the movie for the music, but has more to do with boundless curiosity than disrespecting the jazz masters the movie keeps cutting away from.

A woman’s voice on the soundtrack that says “I don’t really like jazz” might seem to set the tone, but then the performances begin, and although they’re abbreviated, they are glorious. “Summer’s Day” opens with Thelonious Monk, clad in a knockout of a plaid suit, leading his band through his signature “Blue Monk.” I could watch a whole movie of him, but quickly we move on to a runway-glamorous Anita O’Day racing through a double-time “Tea for Two,” a beatific Dinah Washington wearing chandelier-shaped earrings that swing as hard as she does, and Louis Armstrong, whose charisma comes across in a quick interview and a song or two.

There’s also Gerry Mulligan, Mahalia Jackson and — perhaps for that woman who doesn’t like jazz? — Chuck Berry. Just about everyone we see on stage is a legend, including backing musicians such as Max Roach, who isn’t mentioned but was Washington’s drummer. With the release of Miles Davis’ “Kind of Blue” and Dave Brubeck’s “Time Out” just around the corner, this was an era when jazz was a big seller.

In addition to the music, “Summer’s Day,” which is included in the National Film Registry, is a fascinating, focused piece of history. On stage, you may wonder why the only female musicians are singers. As the camera wanders over the faces of concertgoers, you’ll notice that practically everyone wears a natty hat and that the audience appears to be segregated. You’ll also notice how surreally vivid the colors in this restoration are.

One woman, wearing a red dress, a hat with a bright red band, brilliant red lipstick and a shocking red cardigan, is literally a study in scarlet. She doesn’t seem particularly interested in the jazz, so it’s easy to imagine her standing up and assuming a pose for an Irving Penn-shot fashion ad.

The movie is not a fashion ad, of course, although the style on display is impressive. It’s also not about the America’s Cup, or about the privileged few of Newport, or the have-nots we see lurking on the edge of the jazz festival, or, honestly, music. All of those elements are here, but “Jazz on a Summer’s Day’ is best categorized as a free-floating, cinematic essay that probably meant all sorts of personal things to the filmmakers when they shot it more than six decades ago.

Now, though, it feels like a time capsule we’ve just unearthed to remind us of a “simpler” time that was actually just as complicated as our own.