It takes a good 70 minutes for Danish filmmaker Bille August’s period piece “Ehrengard: The Art of Seduction,” to get through its talk-talk-talk opening acts, on its feet and find its fun and its purpose. It’s a 94 minute film, so you see the problem in that.

While it’s grand that Netflix provides work for the esteemed director of “Pelle the Conqueror, “House of the Spirits” and “Night Train to Lisbon,” this adaptation of a Karen Blixen novel (“Our of Africa” was hers), sort of a Danish take on “Dangerous Liaisons,” doesn’t quite pay off. But it comes close.

It’s a gorgeously set and costumed early 19th century tale of royal succession and birth lines in an imaginary duchy, where a seductive painter finds himself commissioned not just for portraits, but to arrange palace intrigues so that a royal heir can be provided.

Cazotte, played by Mikkel Boe Følsgaard (“Land of Mine”) at his most dashing, is a rakish portrait painter to the great royals of Europe. He’s brazen enough to flirt with those sitting as his subjects. The Grand Duchess (Sidse Babett Knudsen of “Limbo”) flushes and blushes and reciprocates his attentions.

But she has a problem. Her boyish teen son and heir (Emil Aron Dorph) doesn’t seem interested in girls. Yet. Perhaps Cazotte can instruct him in the allure of l’amour and the ways of love?

Sure. And while he’s at it, he’ll arrange to put the lad in the company of an eligible royal teen of a nearby duchy (he will paint the family, the boy will pose as his assistant).

But that’s just the start of the “complications” of this affair of the heart, inheritance and a “wager” that the painter can seduce the lovely, aloof and vigorous “maiden in a long line of warriors,” Ehrengard (Alice Esther Leisner).

The performances have a mostly stately nature, rarely hinting at the playfulness we get the feeling the material called for. Every variation of “Dangeous Liaisons,” even one based on a Karen Blixen novel, should be fun.

August, using a script by his son, takes his sweet time setting all this up, as if he’s got “Out of Africa” as his subject matter and planned run time. The better model for him to lean on might have been Orson Welles’ poignant, unhurried and masterfully short film of Blixen’s “The Immortal Story.”

Because once this picture finally rises out of its torpor, it’s damned delightful. The third act has action, intrigues, comedy and a jaw-dropping surprise or two. More’s the pity since the opening acts are such a sexless, humorless drag.

Rating: TV-MA, some nudity, adult situations, mild violence

Cast: Sidse Babett Knudsen, Mikkel Boe Følsgaard, Alice Esther Leisner, Emil Aron Dorph, Sara-Marie Maltha and Jacob Lohmann.

Credits: Directed by Bille August, scripted by Anders Frithiof August, based on a novel by Karen Blixen. A Netflix release.

Running time: 1:34