Pablo Berger’s “Torremolinos 73” clocks in at only 87 minutes and gives the impression of having been chopped clumsily like one of the 1970s-era porn films that are its subject. It’s a shame that he was not allowed to flesh out more of the terrific ideas we mostly only catch glimpses of here, but still the film presents us with a wonderful portrait of the seediness of the 1970s post-sexual revolution.

This is made all the more piquant by the film’s setting in the dying days of Franco’s regime in Spain. The pornography of that era initiated viewers into a sophisticated, adult moral world hitherto concealed by conventional social and religious training. This effect must have been considerably exaggerated for those who had grown up in the puritanical isolation of Spain during the Franco years.

The film begins with Alfredo (Javier Camara) selling encyclopedias door to door – or rather attempting to sell them. We watch his hopeless spiel on behalf of Montoya publishing’s 10-volume history of the Spanish Civil War, bound in leather, which comes with a complimentary bronze bust of Franco.

Alfredo is not doing well. He is desperate to pay the rent, let alone satisfy the wishes of his affectionate but mournful wife, Carmen (Candela Pena), who desperately wants a baby. Just when things seem blackest, Alfredo’s boss, the wonderfully raffish Don Carlos (Juan Diego) of Montoya publishers suggests a way out.

He wants his few remaining encyclopedia salesmen, Alfredo among them, to take advantage of a deal he has struck with a Danish publisher of sex manuals – ostensibly of a “scientific” or instructional” character – by shooting super-8 movies of themselves having sex with their spouses.

Such is the innocence of the time and the place that no one, not even Don Carlos, seems to imagine any other kind of sex being possible.

At first Alfredo says absolutely not. “My wife isn’t showing her bits for anybody, not even the pope,” he insists. But the allure of making 50,000 pesetas, plus bonus, per film proves too strong.

“How many encyclopedias would you have to sell to make 50,000 pesetas?” asks Carmen.

He replies glumly, “154,” with the air of a man who thinks that the number might just as well be a million, since that would be no further out of reach.

Don Carlos assures them that the supposedly “instructional” films will only be seen in Denmark, and that they should “Do it for the progress of science.” To help them, he has brought a Danish couple to show the technologically backward Spaniards how to use the Super-8 movie camera.

Erik (Tom Jacobsen) makes helpful suggestions to Alfredo about his camera technique while Frida (Mari-Anne Jespersen) – obviously a woman of some experience – makes helpful suggestions to Carmen about how to take her clothes off for the camera. When Alfredo has a hard time filming his own lovemaking with Carmen, Erik and Frida offer to let him film them.

Alfredo’s embarrassment is overcome by a growing sense of movie professionalism, which is reinforced by Erik’s own sense of pride at having once been, he tells him, an assistant to Ingmar Bergman.

Soon Alfredo grows dissatisfied with the little vignettes he is filming of himself with Carmen dressed as a nurse or a soccer player or a beauty queen. A showing of Mr. Bergman’s “Seventh Seal” on television inspires him to write a screenplay for a proper movie, which he calls “Torremolinos 73” – a Bergman pastiche in black and white about a young widow who comes to a Spanish resort and encounters a pale lover dressed like Death who reminds her of her husband.

Meanwhile two things are happening. Unbeknownst to Alfredo, Carmen has become a superstar of Danish pornography, recognized in public by vacationing Danes who ask for her autograph.

Also, now that they are relatively affluent, she becomes more determined than ever to have a baby. But test reveal that Alfredo has a sperm count of zero. Adoption seems out of the question because their moral character will be investigated and it will take years anyway.

To Alfredo’s surprise Don Carlos likes “Torremolinos 73” and offers to finance the film. Alfredo will direct – though a Danish crew is to be brought in to help him – and Carmen is to star as the widow. A strapping young Dane called Magnus (Mads Mikkelsen) is to play Death.

But Don Carlos wants to make a few small changes in the script, and Alfredo’s eyes are at last opened to the fact that, to him and the Danes, “Torremolinos 73” was all along just comically pretentious pornography.

More alarming is the fact that he concurrently realizes the film is something else again to Carmen. He has written a film about Death as a surrogate husband because it sounded Bergmanesque, and that’s what filmmaking means to him. But in doing so he has unwittingly provided a surrogate husband for his own wife.

In the end, both he and Carmen have learned the lesson taught by pornography: that sex is a commodity to be used to get what they want. Yet Berger is able to make the rather facile ending upbeat because they have found that among the things they didn’t want after all is one that they still do. It’s too pat and probably the result of having to cram everything into 87 minutes, but everything up to that point is remarkably fresh, intelligent, and well worth seeing.