Fashions in morals, aesthetics, technologies and even media change, like all else. But from this standpoint at the start of the 21st century, as the National Gallery displays 60 Dutch portraits from 1600-1680, we can put forward a compelling claim that Rembrandt is the greatest painter since the Renaissance.

He is figurative, unheroic, republican, a democrat, humanitarian, postFreudian, pro-narrative, antimisogynist, pro-feminist and certainly postmodernist. He’s a history-remaker, an eclectic, an ironist, with bags of self-reflexive knowledge and know-how. He draws and paints the man in the street, the woman next door, the cripple, the vagrant, the exile, the immigrant, the Jew, the negro, the plump female with garter marks on her calves, the plain vulnerable and the vulnerable in the mighty. He has pathos without sentimentality, humour without guile and infinite sympathy. He’s a family man, painting wives lying in bed and babies frightened by dogs.

And he can be very sexy. His paintings of the female nude are highly commendable. There are very few male nudes indeed – a 16-year-old son of Isaac with a knife at his throat, four tortured crucifixions and a couple of male corpses stripped of clothes and skin for two anatomy lessons. Male nudity and violence appear to go hand in hand with Rembrandt.

But with the naked females, it is different. There is no giggling, no sarcasm, no contempt, no cynicism. No knowing, smart-arsed prioritising for the predatory male gaze. Hendrickje standing in a stream, Geertje rising on an elbow in bed. A thoughtful Bathsheba. And clothed but with equally sexy contented domestic intimacy, there is a pregnant Saskia as Flora with a mighty bunch of flowers six months into their marriage, and Saskia as Flora holding a single carnation six weeks from the end of their marriage. If you did want monks enjoying a sexual frolic, and a woman peeing unconcerned on a country road, you’ve got it. No judgments. And curiously very Dutch.

And he could certainly paint; anything and everything, and with exuberance and panache. Perhaps he is everything, in fact, that men and women of the world would want for our better selves; unbiased, unprejudiced and infinitely curious.

In 1642, when he painted the Night-watch, which has inspired my next feature film, he is 36 years old, top of his form, top of his career, the top painter in Amsterdam. He has a big house, a smart wife, and his paintings are owned by the Stuarts in London and the Medici in Florence. In Antwerp, his prints sell at a hundred guilders a time – a fantastic price. He is painting the nightclub set, painting the chattering classes, their wives, grandsons and hangers-on. Tulp, Six, de Graeff, all intermarrying, socialising to keep the Amsterdam fortunes intact and in the right hands.

He’s got good spirit, taking Andries de Graeff to court because his wife objected to his portrait of her husband looking drunk and unsteady. “Paint me as I am,” de Graeff says boldly, not thinking that an upstart from Leiden would dare do such a thing. A David and Goliath law-court case ensues. Rembrandt wins, and de Graeff, the richest man in town, has to pay up.

And then Rembrandt adds to our sympathy by letting it all slip away, losing it. Or he is persuaded, coerced, cajoled and hounded to make it all slip away. Private commissions dry up, consorts are insulted, the fashionable creep away, mortgages foreclosed, public commissions repudiated. Our sympathy increases as his vulnerability increases.

Fifteen years later, he is forced to leave his smart house in the Jodenbreestraat and is living in a one-up-two-down in the Jordaan, the proletariat suburbs of Amsterdam in the shadow of the Westerkerk where he will be buried, and his bones lost, and where Anne Frank will hear bells from that same church tower nearly 300 years later.

We’ve been looking long and hard at all these Dutch portraits, whether they be true likenesses, allegories, archetypes, impersonations of the Old Testament or Ovid, flattering or not flattering.

And we have impersonated those folks in a film drama all about light. Martin Freeman is the 36-year-old Rembrandt, snub-nosed, plump at the midriff, stocky legged. Carel Fabritius (blown up in a gunpowder explosion) and Ferdinand Bol (rich man dying in a bed with gilt sunflowers on the bed-frame) are there. By now, in the 1640s, these are his maturer pupils but still his drinking companions, and Gerard Dou, older still and played by Toby Jones, the painter who painted with a single squirrel hair brush and made almost as much money as Rembrandt himself when the fashions changed and Italian high-gloss, no-brushmarks painting pushed its way right in. And of course the women are there. Saskia, played by Eva Birthistle, and Geertje played by Jodhi May – solid out-of-town nononsense Leeuwarden ladies from up North.

The “painter film” is a small genre of its own: Michelangelo, Rembrandt himself (at least twice), Modigliani, Caravaggio, etc, and none more so than just lately. Picasso, Van Gogh (repeatedly), Bacon, Vermeer, and now Goya have received the treatment. I suppose our major aim in the film Nightwatching, apart from trying to match the Master’s mastery of light, is to demonstrate Rembrandt as social moralist: it contains a murder mystery – the unravelling of which is the heart of the film. And also to regard Rembrandt as an inventor of cinema before the Lumière brothers.

The big three really serious high Baroque painters, Caravaggio, Rembrandt and Velázquez, were all painters of artificial light at a time when serious artificial light became powerful enough to matter. These painters, so they say, were all blessed with retinal handicaps, accompanied, as it were, with advantageous partial blindnesses: Caravaggio apparently had red-colour vision, permitting him to see in high contrast, with no or little differentiation between black and red; Rembrandt had an astigmatism in his right eye and was thus prone to the advantages, to a painter, of monocular vision – think of that cliché of a painter squinting through one eye; and Velázquez had an unstable and floating left-eye retina that, through unsteady focus control, allowed him to to essay movement as well as light – look at the spinning wheel in The Fable of Arachne, and the fluttering, never-still hands of the maids in Las Meninas.

We tried to rise to the challenge in the film, remaking, with high definition digital tape, that upper right-hand corner space of Velázquez’s Las Meninas – the area between the walls and ceiling has been described as the greatest bit of painting ever – a painting which is just and only and magnificently a painting of a block of darkly contrasting air. We, too, attempting a grand response Rembrandt image of light, tried to film a block of air that insubstantionally floats, irrespective of walls and ceiling.

Godard said that the cinema was the truth 24 frames a second. Can painting go better and say that paintings are the truth for all time? What’s a second in cinema time if you can have an eternity in painting time? Cinema has come and gone in 112 years. What, then, is the age of painting?

Dutch Portraits: The Age of Rembrandt and Frans Hals is at the National Gallery, Salisbury Wing, London WC2 (www.nationalgallery. org.uk 020-7747 2885), opens Jun 27, until Sept 16

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