What is it about black and white celluloid that makes its modern digital equivalent feel so flat and washed out?

Is it the texture, the nearly-invisible but implicit “grain” and sharpness? The contrast between light and shadow, the many shadings of grey, the far darker blacks, the physical/chemical limits of film’s depth-of-field that mimic the eye?

I fret over this every time I dive into a much-praised modern monochromatic movie or even Disney’s “WandaVision,” wondering what it is that makes “Roma” and “Mank” leave me cold visually.

There were hints of the disappearing art of lighting and shooting in black and white as early as the 35MM “Schindler’s List,” which still has scenes of stark monochromatic beauty that nothing produced in black and white today can match.

But to really see the difference, a vintage production by a master filmmaker working in the medium is what you look to for comparison.

John Frankenheimer’s 1964 thriller “The Train” is a flawed gem, basically a fictionalized, action-amped story from the pages of the “Nazis stealing art” saga that “The Monuments Men” documented.

It was filmed in glorious “European widescreen” in French-processed black and white. That makes every information-packed image of Frankenheimer’s exquisite mise en scene pop, sometime to a breathtaking degree.

Watching it again for the first time in many years, I was struck by how much better it still works than George Clooney’s more historically-accurate but still bowdlerized “Monuments Men” of 2014.

Both films are based on historical accounts of the risks of wartime destruction and the Nazi looting of the patrimony of Western Civilization, the Great Artworks of Europe. Both are fictionalized, especially when it comes to the heroine of that saga, the French art historian and curator Rose Valland, whose record-keeping was the German Philistines’ undoing at war’s end, tracking the artworks she was not able to hide from thieves to those who did the stealing.

Valland’s name was changed in both films, although “The Train” comes closer to the real Rose, even if the incident portrayed never happened.

Screenwriters Franklin Cohen and Frank Davis had the clever idea of putting this story on heist picture footing and setting it literally in motion. An urbane, amoral Nazi (Paul Scofield) spirits scores of paintings and artworks out of Paris as it is about to fall to the Allies in 1944. The Rose Valland figure (Suzanne Flon) sounds the alarm to the Resistance. And the job of stopping this train hauling the art falls on the railyard supervisor Labiche, played with brute panache by Burt Lancaster.

The artwork is a wide array of genres, from impressionist masterpieces to the “modern” works the Nazis banned as “degenerate art,” thus working in another of Germany’s crimes against civilization (art destruction and censorship) into the story.

Our villain is a classic “type,” polished, well-spoken — a sophisticate.

“Beauty belongs to the man who can appreciate it,” Col. von Waldheim (oopsie) purrs. Right.

This trope is like the serial killer as Man of Letters and Taste cliche that “Silence of the Lambs” helped perpetuate. No, serial killers are statistically most often truck drivers. And the Nazis were largely oompah-music loving thugs and goons — not unlike nationalist cretins the world over, mouth-breathing lovers of “country” music, whatever fits that definition in whatever country, the US to Brazil, Russia or the Philippines, in the present day.

What brings “The Train” to life are its action beats — chases and strafings and bombings and sabotage, which includes here renaming whistle stops to fool the Germans on board that the art-filled train is heading in a direction it isn’t.

Frankenheimer spent a lot of United Artists’ money and a lot of screen time on a movie that only has to hint at World War II in most cases. We see but a single (distant) British Spitfire, a couple of bombers, a railyard turned into devastation.

But every immaculately-framed shot packs in characters, background and information — anti-sabotage posters in a rail clerk’s office, sharply focused huge closeups of actors in the foreground, stars in the middle or background, and sometimes the exact opposite, built around the big, chiseled and soot-stained face of Lancaster, playing a character who can’t get over the fact that they’re being asked to die for art.

“You know what’s on that train? Paintings. That’s right, paintings. Art. The national heritage. The pride of France. Crazy, isn’t it?”

Lancaster is the linchpin who holds this long, smoky dash across France together. It’s a classic movie star turn, with gravitas and sparkling flashes of his acrobatic past. He manhandles heavy machine parts, casting brakelines to fix a sabotaged engine as if he’s done it all his life. He clambers through windows, over walls and up roofs, and in his most memorable bit of business, slides down a long switching station ladder to the tracks like a guy who’s worked the rails since childhood.

The picture has too much bloodshed to allow for the lighter moments a movie like “The Monuments Men” went for. The dialogue is melodramatic and arch, the characters archetypes. But in simplifying the stakes, narrowing the focus, giving us a fixed villain, and shooting in “WWII period piece” black and white, Frankenheimer gives us a riveting ride through a war fought over values and fundamental freedoms — among them, the freedom to create, value and appreciate whatever artistic expression you choose, and not just the oompah music, idealized landscapes and muscular propaganda of the tasteless goons in charge.

And he did it in the black and white tones that don’t just look but actually feel like the era they’re depicting, not a cheap, washed-out facsimile of that past.

MPAA Rating: unrated, violence

Cast: Burt Lancaster, Paul Scofield, Jeanne Moreau, Suzanne Flon, Michel Simon, Albert Rémy and Wolfgang Preiss.

Credits: Directed by John Frankenheimer, script by Franklin Cohen and Frank Davis. A United Artists/MGM release on Tubi, etc.

Running time: 2:13