Some films last through the ages. Others are products of their time, lost relics of a bygone era that mean little to later generations. And then there are those that fall into a strange middle ground, capturing the obsolete zeitgeist of a period while feeling wholly timeless. Antonioni’s 1966 “Blowup” is one such film.

Both revolutionary and controversial during its time, “Blowup” arrived at the apex of a new generation: months before “Sgt. Pepper’s” sparked the love parade, and years before “Easy Rider” created a new breed of revolutionaries. As with many movies from the cynically ultramodern 60s (and a lot of the films in the Broadway Cinematheque’s “Modern Classics” screenings for that matter), plot takes a firm backseat to the art house aesthetics. The modish London photographer protagonist (David Hemmings) has maybe accidentally snapped a murder through his lens, which starts the story. But like an avant-garde McGuffin, this is just a meaningless plot point around which Antonioni can weave his threads of new-wave novelty and social satire.

But that isn’t to say it’s a bad thing—for while many movies of the time were caught up in the complications of formal structure, “Blowup” aimed for both innovation in its form and to capture the innovations of the era. Antonioni adored and abhorred the period, and used the screen as his canvas—the fast cars and faster women, the free love and hypocritical materialism, the indifferent youth high on acid listening to Jimmy Page. Like a day-in-the-life documentary, we follow our photographer as he investigates, snoops around and then gives up, all mere digressions and asides to Antonioni’s real message: the film is partly a love song to the swinging 60s, and partly a warning about just how badly ennui and indifference can stunt a generation.

And sure, it’s not as controversial as it once was, nor as relevant. But it’s an important film that, like many others that have come to be known for defining a generation, is easily misconstrued as being empty and overblown. And to be honest, I still prefer Brian DePalma’s remake/rip-off, “Blow Out.”

4 Stars by Pavan Shamdasani.

Directed by Michelangelo Antonioni. Starring David Hemmings, Vanessa Redgrave. Category IIB. 112 Minutes.