Every artistic discipline has its stragglers, artists who begin auspiciously, then spend years on false starts, spiritual enlightenment or gardening before churning out a new opus. Director Kimberly Peirce took nine years after her Oscar-winning film “Boys Don’t Cry” to come back with “Stop-Loss.” Last week the Pulitzer Prize for fiction went to Junot Diaz, whose novel “The Brief Wondrous Life of Oscar Wao” was 11 years in the making after his debut short-story collection, “Drown.” But pop music isn’t literature or film. It carries an aura of disposability that’s hard to rise above. The longer it takes for an album to go from theoretical to actual, the less chance there is for a welcome return. (See Guns N’ Roses’ “Chinese Democracy,” still “forthcoming” after 14 years, and the follow-up to My Bloody Valentine’s “Loveless,” released in 1992.) If a bell curve were plotted to determine the amount of time required for anticipation to become apathy, “Third” would land just past its peak. If it had been released, say, eight years ago, the album would have felt like a natural addition to the Portishead discography. But it wouldn’t have been possible then. “If we had tried to make this record years ago, I think we would have been less focused,” says Utley. “The result just wouldn’t have been very interesting music.”

You could argue that there’s an artistic advantage to spending so many years lying in wait. “It’s been so long that you can’t really compare this record to the older ones,” says Barrow. Of course, that won’t stop fans—the ones who’ve had a decade to imagine what a new album might sound like—from doing it anyway. “Third” is at least somewhat respectful of the Portishead brand. New songs “Hunter” and “Threads” would have been at home on either of the band’s first two albums. But on “Third,” it does what any band should be doing by album No. 3—expanding its palette. “The Rip,” “Silence” and “Small” take their cues from ’70s psychedelic and experimental rock. In a complete departure, “Deep Water” is populated only by Gib-bons’s plaintive voice and a ukulele. The hip-hop influence has vanished—the samples have been abandoned entirely—but the album maintains the spooky, spacious vibe for which the band’s become known.

Real Portishead fans know that it was almost inevitable that they took so long to return. For the second album, rather than use samples of other artists’ records, as they had done on their debut album, “Dummy,” they opted for the arduous process of recording live instruments to tape, having the recordings pressed to vinyl, then deliberately abrading the vinyl to achieve an authentic, crackly sound. The track “Seven Months” was named after the length of time it took to write, but Barrow later admitted in an interview that it wasn’t quite accurate. They came up with the name, he said, before the additional seven months necessary to perfect the four-minute tune. That perfectionism clearly played a role in Portishead’s 11-year drought. “We have to operate this way to make it work,” says Utley. “I don’t even understand the criticism of perfectionism, really. It’s just about wanting things to be correct.” All of which has only raised expectations among the long-suffering fans. But the band believes that the covenant between artist and fan dictates that it put out good music, not fast music. If “Third” is well received, it’ll serve as further proof that true love waits. If not, well, on to the next album. When will it be out? “Who knows, maybe three weeks from now,” Barrow says. “But probably not.”