*** 1/2 BOB DYLAN “Under the Red Sky” <i> Columbia</i> : <i> Albums are rated on a scale of one star (poor) to five (a classic). : </i>

It’s not exactly blood red (or “Blood on the Tracks”), but “Red Sky” joins the recommendable half of Dylan’s output over the last 20 years, the product of strong celebrity producers rather than a slapdash patchwork.

With Don and David Was behind the boards, “Red Sky” doesn’t have the mystical aura that producer Daniel Lanois crafted or the lyrical focus Dylan regained for last year’s “No Mercy.” And despite guest turns from George Harrison, Bruce Hornsby, Elton John, Slash, the late Stevie Ray Vaughan and his brother Jimmie, the backing seems a bit anonymous. But it may be the most fun release from Zimmy in ages: a blues-based romp, with Dylan as the Crawlin’ Kingsnake.

The opening “Wiggle Wiggle” is an inconsequential goof, but it sets the tone, rocking merrily along. Not lost in the spirit are gritty warnings against concentration of power (the easy-target “TV Song” and semi-paranoid “10,000 Men”) and truly tender, spiritual character studies (the title song, “Born in Time” and “God Knows”), before the album wraps up in fine fashion with the jumpin’ roadhouse raver “Cat’s in the Well.”

Still, there’s an underlying feeling that Dylan kinda walked through the project . . . again. He may treat his records like throwaways, but this one’s a keeper.