One can hardly imagine a more 21st-century problem than being caught up in a broadband outage minutes before an online-booking session for Venice International Film Festival.

Such was the crisis last weekend. Like every other big film festival, Venice now requires visitors to have virtual tickets on their smartphone before entering the auditorium. You didn’t get that in Henry James or Thomas Mann. Or in films by Nicolas Roeg or David Lean.

Nowhere else on Earth has been so preserved in artistic aspic. Modernity is not supposed to happen here. Even the most contemporary films and TV series move about a city recognisable as the one that welcomed a sloshed Lord Byron.

But what about the tourists? Well, Byron was a tourist. The annoying visitors were featuring in stories about Venice when a doge still ruled the republic. “Though there are some disagreeable things in Venice there is nothing so disagreeable as the visitors,” James wrote in 1882.

In the same author’s dreamlike The Wings of a Dove a character seeks to escape the “amiable American families”. The addled, vain Gustav von Aschenbach, doomed protagonist of Mann’s Death in Venice, sees himself as being above the vulgar hordes sharing his Lido hotel.

Yet none of this dampens the romantic affection writers, poets and film-makers bring to their depictions of Venice. Federico Fellini set the seedy side of Rome alongside the glamorous one in La Dolce Vita. Many French film-makers have examined the social inequalities in Paris.

But when fictional crime comes to Venice, as in Patricia Highsmith’s The Talented Mr Ripley, it does so amid the accoutrements of the Renaissance. What psychopath could be unhappy living out his guiltless days amid such antique beauty?

Just think of the most famous films set there. Even those soaked in horror acknowledge the romance and wave away contemporaneousness.

The untouchable Don’t Look Now is a case in point. Adapted from a story by Daphne du Maurier, Nicolas Roeg’s film, from 1973, follows an architectural restorer and his wife as, visiting the city in cooler months, they encounter possible communications from their late daughter. Donald Sutherland is sceptical as the husband. Julie Christie, as the wife, is prepared to believe. It all ends in a confused, ultimately murderous pursuit through the city’s labyrinthine alleyways.

From the archive: Nicolas Roeg: the director who took the familiar and made it strange

Yet two or three generations of film enthusiasts have visited Venice in pursuit of the locations from Don’t Look Now. My very first time on the main island was taken up with a confused, apparently hopeless wander through narrow thoroughfares that constantly frustrated orientation. The hotel seemed inaccessible to anything other than fish.

After 15 minutes or so of this my friend and I inevitably began making jokes about imminent attack by (spoiler alert) tiny maniacs in red raincoats. Nothing seemed to have changed in the 50 years since Roeg shot Don’t Look Now. Little would have changed in the 50 years before that.

The most beautiful depiction of Venice in a feature drama is surely found in David Lean’s Summertime, from 1955. We are again among the tourists as Katharine Hepburn takes the train across the bridge connecting Venice to Mestre for (as it transpires) romance with the suave Rossano Brazzi.

Two years before Lean leaned into epic with The Bridge on the River Kwai, he conjured up a magically picturesque Venice in painterly Technicolor. The struggling postwar world is elsewhere. All is elsewhere.

From the archive: Five indisputably great David Lean pictures

For the attendee at Venice film festival, however, the key film is surely Luchino Visconti’s 1971 adaptation of Death in Venice. Not because I spend my days, as does Dirk Bogarde’s von Aschenbach, weeping in a deckchair while the make-up runs down my cheeks, but because, like the festival, much of the film takes place on the long, thin Venice Lido. There are motorcars. There are smooth, modern roads. There are many buildings constructed after the unification of Italy.

The creative antiquation of Venice that must so annoy the locals – do they see these films as we see sentimental Micksploitation movies? – no longer has any purchase here. No. Don’t Look Now and Summertime do not come to mind on the morning commute. This does summon up Anthony Minghella’s film of The Talented Mr Ripley.

Patricia Highsmith: a talented writer who always let rip

There is something else. We are at an international film festival. At Cannes and Venice, during the event, one feels cordoned off in a privileged space where little local colour intrudes. Everyone is huddled over their phone trying to grab that ticket they missed a week earlier. English is spoken by American, Brazilian, Japanese and German folk.

The cinematic locusts descend for a week or two, do their infernal business and then swarm elsewhere. If the films and novels are any guide, the city remains unchanged by our brief hermetic appearance.