If “Sin City” were twenty minutes long, it would be a breathtaking cinematic treat. But at over two hours, Robert Rodriguez’s loving effort to transfer three of Frank Miller’s dark comic books (or, for those who insist on rhetorically elevating the genre, graphic novels) to the screen with as much visual (and tonal) exactitude as possible proves way too much of a good thing. Over so long a haul the splendor of the images, which feature stunning black-and-white vistas and characters periodically set ablaze with shards of color (mostly reds and yellows), comes to seem pretty vacuous in the absence of any content deeper than the pulpiest pulp. As a whole the film is the sort of obsessive labor of love that one may respect, but is likely to tire of pretty quickly. It’s the bad-boy equivalent of Francis Ford Coppola’s “One From the Heart.”

“Sin City” isn’t a narrative so much as a chain of brooding, vaguely interlocking tales set in a single gloomy metropolis, all featuring the sort of ridiculously over-the-top hard-boiled dialogue and situations that one might take as either a send-up of noirish conventions or an extravagant tribute to them; you might think of it as a cinematic equivalent of one of those anthology comics that used to be popular in the fifties (and gave rise to movies like “Creepshow” and TV shows like “Tales from the Crupt”). First comes a prologue featuring a tuxedoed Josh Harnett as a laconic assassin who disposes of a luscious-looking femme fatale on a balcony overlooking the city skyline. Then we cut to the first part of a tale about Hartigan (Bruce Wiullis), a hard-bitten cop just about to retire because of his bad ticker, who rescues a kidnapped girl named Nancy from the clutches of a pederast (Nick Stahl), despite the fact that the young man is the son of the powerful senator Roark (Powers Boothe) and Hartigan’s partner (Michael Madsen) proves a distinctly unreliable ally. The focus then switches to another macho protagonist, the hulking but honorable brute Marv (Mickey Rourke), an ex-con whose quest to track down the murderer of a prostitute (Jaime King) for whose death he’s being framed takes him, along with the dead girl’s twin sister, over the brutalized body of a preternaturally efficient serial killer (Elijah Wood) to a corrupt and degenerate churchman (Rutger Hauer) who just happens to be Rourk’s brother. The picture then cuts to a story involving a more conventionally heroic figure, Dwight (Clive Owen), who helps the ladies of the red-light district led by his inamorata Gail (Rosario Dawson) dispose of the corpse of a sleazy undercover cop named Jackie Boy (Benicio Del Toro) whom her girls have unknowingly slain; but there’s a further complication on the part of a mercenary leader named Manute (Michael Clarke Duncan) who aims, it appears, to take over the city’s free-wheeling area. Then the flick segues back to the Hartigan thread as the cop is released from prison after serving a long term engineered by the senator, only to find that he and Nancy (now played by Jessica Alba) are being pursued by a grotesque creature referred to as Yellow Bastard, which looks rather like Gollum transformed by a few years of overindulgence on rich food and slapped with a bright new coat of paint. After the inevitable confrontation between the ex-cop and the creep, we revert briefly to Hartnett’s assassin dealing with another femme, and again fatally.

There’s no point searching for any deep meaning in “Sin City”–what you see is, quite frankly, all you get. Of course, Rodriguez and his alleged co-director Miller (with a small assist from “guest director” Quentin Tarantino, who reportedly helmed one scene in the Dwight segment) milk the single-note material for all it’s worth, with Rodriguez in particular obviously reveling in the weird angles, glistening monochrome images and pulsating rhythms. His work recalls Orson Welles’s remark about the movie set representing the best electric train he’d ever had the opportunity to play with; the picture’s flamboyance represents the same sort of boyish enthusiasm that energized every frame of “Citizen Kane,” but a much less refined sensibility. Welles’s film might not be the most profound examination of journalistic power imaginable, but there’s always a sense of seriousness behind the bravado. Here there’s nothing but a juvenile fascination with macho violence and female exhibitionism (there’s barely a woman to be seen who isn’t clothed in the most revealing possible garb and who doesn’t act in the skankiest possible way). Even the underlying emphasis on rampant establishment corruption–in both state and church–represents little more than typical adolescent rebelliousness and anti-authoritarianism. If you scratch the gorgeously seedy surface of “Sin City,” you’ll find zilch beneath it.

Nonetheless, it’s visually an amazing achievement, for which Rodriguez and his design team (set designer Rob Simons, art and set decorator Jeanette Scott, visual effects producer Keefe Boerner and the team at Troublemaker Studios) deserve accolades. Within this context the actors take a decidedly back seat, but Willis, Owen and Rourke cut their macho figures with aplomb and deliver the purplish narration with appropriate tongue-in-cheekiness; Rourke, encased in makeup that makes him look like a Dick Tracy villain, makes an especially strong impression. In smaller roles Del Toro, Wood and Stahl stand out, the first for his ghoulish glee, the second for his nimbleness and gruesomely calm demeanor even while being literally dismembered, and the third for–well, let’s just say reasons of makeup tolerance. The women are notable mostly for willingness to reveal more than their parents might ever have wished, but Devon Aoki demonstrates some nifty moves as a super-efficient killer, and Alba mingles the sultry and the innocent with some panache.

But it’s not any of the human beings you’ll remember from “Sin City.” They’re even less real than the figures in “Dead Man Don’t Wear Plaid,” an equally empty exercise in style from 1982, who were actually recycled from old movies. But that Carl Reiner movie, which was also based on a single repetitive gag, at least milked it for only 89 minutes rather than 124. The excessive, and arguably numbing, length of this adolescent stunt suggests that perhaps Rodriguez, who works in a sort of splendid Austin isolation, is suffering from a kind of cabin fever and would benefit from a bit of old-fashioned studio oversight. The real masters of noir certainly did.