It was way back in 1966 that Dr. Seuss’ Grinch, arguably the writer’s most famous character, first made his appearance on the screen—the small one—in an animated TV special, in which Boris Karloff provided the voice, doing both narration and the Grinch’s dialogue. Now Illumination Entertainment, the outfit that adapted another Seuss book, “The Lorax,” for the big screen six years ago, has taken up the story of the wicked green one’s effort to steal Christmas from the residents of Whoville. Theirs is, in overall spirit, a pretty faithful adaptation, preferable in that respect (and others) to the Ron Howard-Jim Carrey live-action misfire from 2000; but except in terms of the vibrancy of the images, it too pales before Chuck Jones’s humbler half-hour classic.

The brevity of the time slot, of course, meant that Jones was able to stick very closely to the text and tone of the original; there were some minor additions, including musical ones, but the 1966 film was essentially Seuss. Anyone expanding the simple story into a feature necessarily must resort to padding. Howard and his screenwriters, Jeffrey Price and Peter S, Seamans, added a good deal of incident, much of it misguided, and the result was painful.

The directors of this new version, Yarrow Cheney and Scott Mosier, and scripters Michael LeSieur and Tommy Swerdlow add incident as well, but much of it is composed of slapstick action for the Grinch (voiced by Benedict Cumberbatch) and his ever-loyal dog Max, though they add a third partner in pratfalls in the form of an oversized reindeer the Grinch tries to enlist in his nocturnal heist, as well as a few appearances by a little goat with an extraordinarily loud bleat. This is harmless, if overextended stuff. (There is a particularly odd sight gag that shows the Grinch wearing tightly-whities in bed, and then putting on “pants” of furry green after he awakes.)

Other expansions are less happy. Like the picture, this one feels compelled to add a backstory to explain the Grinch’s bad humor and hatred of Christmas. It’s derived from Dickens, and clumsily so. We do not need to be told where his grinchiness comes from.

A third major expansion has to do with the home life of little Cindy Lou (Cameron Seely), here no toddler but a feisty, chatty kid, and her single mom Donna (Rashida Jones), which results in lots of sitcom-style banter between mother and daughter and plenty of interaction between the child and the Grinch. That’s far less satisfying material, more sickly sweet than Seussian. It also allows for some scenes involving Cindy Lou’s “posse,” the most notable of whom is a cutesy kid named Grooper (Tristan O’Hare); this is utterly extraneous stuff, and for the most part pretty pallid.

Meanwhile the doggerel of the original, sad to say, suffers noticeably this time around. A few lines are occasionally repeated in a wimpy voice by Pharrell Williams. He’s certainly no Karloff.

As for music, there are a few brief allusions to the songs from the television special, but no new numbers, though the Grinch sometimes plays a huge organ like a green Phantom of the Opera The major stuff is in the form of Christmas carols (appropriate, since, as has been mentioned, the obvious precursor of Seuss’ story in Dickens’), but it seems a bit odd that the one that is most prominently used is “God Rest Ye, Merry Gentlemen,” with its mention of Christ—though otherwise the Whoville celebration is utterly devoid of any religious element.

The voicework is spotty. Seely and Jones are conventional spunky, and Kenan Thompson gets off a few blustery laughs as a Whoville resident named Bricklebaum, who irritates the Grinch no end. That leaves the question of Cumberbatch’s Grinch. The approach is certainly very different from Karloff’s: more reedy than growly, wheedling rather than gruff. Frequently he sounds like Paul Lynde, with a slight quiver to the voice. It’s certainly a different interpretation, though one that takes some getting used to.

So what’s the overall assessment of this latest “Grinch”? In terms of visuals, it’s outstanding, an example of computer-generated animation that matches the best Illumination standards, and both kids and adults should appreciate that. But while bright and shiny and energetic, it also pads the original to its disadvantage, proving once again that bigger and longer is not necessarily better. Jones and Karloff still rule the Whoville universe.