It took a while to discover why “Sin City” fails while co-director Robert Rodriguez’s buddy, Quentin Tarentino, continually creates rich, demanding masterpieces. Both filmmakers have mastered their craft, orchestrating color and music to heighten their stories. Both utilize explicit violence and paint their celluloid with enough gore to make Jason Vorhees’ knees weak. But when audiences view a Tarentino film, his passion for the medium is so palatable it’s as if he’s biting into a succulent orange and sharing it with each of us. Rodriguez just appears to be showing off, displaying how smart he is.

Based on co-director Frank Miller’s graphic novel, the film interweaves three stories with bookends regarding a mysterious salesman (Josh Harnett, “Pearl Harbor”). In the first story, a hideous looking loser (Mickey Rourke, “9 1/2 Weeks”) avenges the murder of a one-night stand. He discovers a farm lorded over by a cannibalistic boy (Elijah Wood, “Eternal Sunshine of the Spotless Mind”). The second story is set in Old Town where the whores rule over with deadly force. A corrupt cop (Benicio Del Toro, “21 Grams”) threatens to abolish the truce between the girls and the cops, so head-whore Gail (Rosario Dawson, “25 th Hour”) and her ex-lover (Clive Owen, “Closer”) hatch a plan to keep the order. In the last story, a framed former cop (Bruce Willis) tracks down a girl whose life he saved eight years before, an 11-year-old kidnap victim who has blossomed into a striking stripper (Jessica Alba, “Fantastic Four”).

Visually, “Sin City” is a vivid, crisp experiment. Motifs of rain and wind fill the screen and illustrate the visual irony, these two cleansing actions occur in a town without salvation. “Sin City” is a world where nothing grows. Trees in the forests have no leaves, no life. High angle shots give the impression that heroes tower over their environment.

Rodriguez and Miller manipulate the colors, combine stark black & white images with hints of hues. An entire scene will be color-free with the exception of a femme fatale’s red lipstick. Blood flows like thick white paint, and to add to the surrealism, when people are shot, they shatter like porcelain dolls.

Some images are fascinating. A man forced to bite his own cut off hand to loosen the grip on his gun adds Grand Guignol mischievousness.

However, there’s monotony to its violence. Eviscerations, decapitations and scalpings all get tiresome quickly and in “Sin City,” little else occurs. After a while, there is little difference between “Sin City” and Camp Crystal Lake.

It comes to no surprise to discover that Tarentino himself had directed the one scene that captured the humanizing elements missing in others. A macabre roller-coaster ride of a scene between a mocking corpse and Clive Owen manages to encapsulate the comic book flavor while remaining cinematic.

Of the vast cast, last year’s Oscar nominee Owen excels most, displaying magnanimous heroism with pulp cynicism. Also, enjoyable, Del Toro exposes his wide eyes like a German expressionist actor. Resembling the Joker sans pancake, he savors every malicious moment.

The long-winded script weighs down the rest of the cast. They speak lines they don’t appear to believe and that contributes to the film’s soullessness.

True “Sin City” is gritty, sleazy and pulp, but it’s never engrossing. The characters never come to life and in the end; it’s as affective as flipping quickly through the pages of a brilliantly drawn comic book. Grade: B-