Thomasin Savaiano as Nicky, and David Bryan Jackson as Bernard Berenson in The Washington Stage Guild’s The Old Masters. (C. Stanley Photography)

“The Old Masters” turns on a famous case about one of the paintings hanging in the National Gallery of Art, “The Adoration of the Shepherds.” According to the gallery’s Web site, the painting is “almost unanimously accepted as Giorgione’s work.”

The alternate view is that it was painted by Giorgione’s pupil, Titian, and thereby hangs a juicy tale in Simon Gray’s 2004 drama. The difference could mean millions of dollars, and the immediacy of that cash — plus the huge drivers of ego, jealousy, looming fascism (it’s 1937 Italy) and a new class of American millionaires — makes “The Old Masters” a good, old-fashioned, high-veneer play about deliciously grubby behavior.

Gray originally called the play “The Pig Trade.” He admitted that he dawdled about getting to the meat of things, and the only thing that slows the zesty show at the Washington Stage Guild is a long first scene padded with exposition about debt and family frictions that seem piddling. At least we get situated in the Italian villa of I Tatti, and we meet Gray’s version of the noted 20th-century art historian Bernard Berenson.

Things pick up when the tweedy Berenson has a delicate little mercantile conversation with a genteel go-between named Fowles, an employee of the tremendously influential art dealer Joseph Duveen. There is cool intrigue in this peculiar exchange, as played by David Bryan Jackson (a professorial Berenson) and Steven Carpenter (all rectitude as the savvy messenger).

Then in blows Duveen, played by Conrad Feininger, and the play is off to the races. Duveen the broker and Berenson the authenticator were titanic figures in the first half of the 20th century, and Feininger’s outsize turn as Duveen lifts the show. Feininger looks like Daddy Warbucks and sounds like an engine-braking truck whenever he lets his baritone voice roar. He does this hilariously when his character bellows what the poor painting in question would say if it could talk.

“I’m a Giorgione!” goes the message, more or less. That, Duveen notes, is where the money is. Titians are everywhere. Giorgones are scarce.

Every bit as funny is Duveen’s savage impersonation of dime-store millionaire Samuel Henry Kress, and it’s here that Gray really starts piercing the rough edges of his characters. Is Duveen any different from the kind of crude horse-trader he pretends to disdain? Is Berenson?

The second act is largely concerned with these two bulls locking horns, and it’s a terrific match. Feininger’s Duveen is by no means merely bluster, and Jackson’s Berenson turns out to be a would-be hero mired in deep shades of gray. Their negotiations are pure hardball, yet their rapture is infectious each time they face the masterly paint on the disputed canvas.

Gray’s slow-brewing play makes lamentably thin figures of Berenson’s wife and secretary in that drab first scene. But Jewell Robinson as the wife, who knows paintings and used to smuggle them, and Thomasin Savaiano, playing the secretary who is also Berenson’s mistress, make good once Gray puts flesh on the characters.

The best thing about director Laura Giannarelli’s straightforward, handsomely designed production — it’s in the Stage Guild’s usual base, the intimate Undercroft Theatre at the Mount Vernon Place United Methodist Church — is how unimpressed the actors are by the highbrow talk. They keep an easy humor in the air, even as they let you know that between all these operators, there’s blood on the floor.

The Old Masters

by Simon Gray. Directed by Laura Giannarelli. Set, Carl F. Gudenius; lights, Marianne Meadows; costumes, Sigrid Johannesdottir. About two hours and 15 minutes. Tickets $25-$50. Through Jan. 26 at Mount Vernon Place United Methodist Church, 900 Massachusetts Ave. NW. Call 240-582-0050 or visit