BY BOB STRAUSS >Film Critic

Errol Morris has probably made his most artful documentary yet with the Abu Ghraib inquiry "Standard Operating Procedure." As is usually the case with the director of "The Fog of War" and "The Thin Blue Line," it leaves you wondering if artful and documentary should really go together.

Morris has bitten off more than one big theme here. Not only does he obsessively chronicle the abuse of Iraqi detainees in the infamous prison by U.S. personnel, but the film asks us to question basic concepts about visual evidence. Hundreds of the photos taken by the guards of themselves and their stress-positioned, stripped, terrorized and degraded captives are creatively arranged and conscientiously examined throughout the movie. Morris even brings in Brent Pack, the military's criminal investigator who was tasked with making court-martial cases out of the pictures and some video, to explain just how tricky some visual evidence can be.

The majority of interviews are with a half-dozen of the MPs convicted of prisoner abuse. And while hearing their points of view (although some of them already appeared on HBO's "Ghosts of Abu Ghraib" that aired last year) is invaluable, the photos in Morris' film seem to contradict them. An unexpectedly articulate Lynndie England, for instance, blames her behavior on being a woman in love with a bad man in a male-dominated subculture. Still, England looks like she's having the time of her life in those photos controlling the naked Arab men.

There's been a bit of brouhaha in the documentary community since word got out that Morris paid some of the soldiers for their camera time. Whether or not this is standard procedure in doc-land remains a question.

Morris, though, long ago burst the boundaries of established documentary principles by restaging events he could not possibly have been there to film, and he really goes to town with that in "S.O.P." - not that he tries to cover it up. Between the rich trove of pictures actually taken at Abu Ghraib and Morris' exquisitely horrific dramatizations of informed speakers' testimony, we're immersed in the confused, justifiably paranoid and morally schizophrenic hell of the prison.

Surely, the low-ranking MPs (and their boss at the time, the absolutely furious Brig. Gen. Janis Karpinski) were scapegoated for policies and incompetencies hard-wired into the whole operation. But nonetheless, we come out of "S.O.P." asking, How much of what we've seen was true?

There's likely a more objective report to be made about Abu Ghraib, but in the meantime, we can't ask for a more depressing one than Morris' film. Somehow, though, relentless unpleasantness may be the most appropriate quality of this movie that disturbs in so many different ways.

Bob Strauss (818) 713-3670 bob.strauss@dailynews.com

review>

STANDARD OPERATING PROCEDURE

>R: violence, nudity, sex, language.

>Director: Errol Morris.

>Running time: 1 hr. 58 min.

>Playing: Town Center 5, Encino; Playhouse 7, Pasadena; Sunset 5, West Hollywood; Landmark, West L.A.; Westpark 8, Irvine.

>In a nutshell: Exhaustive, exquisitely made and totally depressing documentary about the Abu Ghraib atrocities gives the soldiers involved ample chance to present their sides of the story, but Morris' methods leave questions.