There is an otherworldliness about London’s National Gallery which envelops anyone crossing its iconic threshold. Documentarian Frederick Wiseman has a singular ability; to immerse himself in the world of a great institution, distill its energy and translate its intricate machinations into a compelling narrative without sacrificing its quirks. As demonstrated by previous projects, and typified by La Danse and At Berkeley, he does not pander to audiences by laborious show and tell, but rather assumes stimulated minds will rise to the occasion – however aspirational or unfamiliar the subject matter.

He is seamlessly matched in this unwavering belief by the director of the board of his latest subject. The prospect of this iconic grande dame being tarted up with Sport Relief banners for the marathon is unthinkable to the very British gent. The new brooms on the board may concern themselves with end users, public perception and other ghastly conceits but HE has not forgotten their unfortunate Harry Potter experience. These early shades of eccentricity – though pleasing – imply a predictable canvas for the forthcoming footage that the veteran director cleverly washes away.

This is a love letter to the National Gallery which beguiles like a visual tone poem. The secret pleasure of people-watching celebrated in the gurning, grimacing, gut reactions to the art. That opulent, beautiful, brutal and baffling art – masterworks so familiar they resemble props beside extraordinary faces, perishables and places from history. Snapshots of the past suspended above the “me! me! me!” tug of now. And the custodians each carefully safeguarding their futures through science, storytelling, budget-juggling and love. Proud parents sharing the paintings’ truths with visitors from all seven ages of man and their associated attention spans.

What evolves is a fascinating study of the multifaceted ways one can experience a painting. Offering the scientist’s perspective, the conservationist’s, the intrigued amateur’s and the aimless wanderer’s. A tour pausing by Stubbs’ Whistlejacket reveals the artist explored equine anatomy by buying, suspending and stripping horse carcasses back to the bone. That this powerful study of musculature and  energy – tribute to a legendary racehorse – began Hirst-esque from death. An X-ray of another masterpiece reveals a painting within a painting – a secret expression of cost or time or frustration made lifetimes ago – bringing the artist alive to an astonished room. Blind and partially sighted visitors in a classroom vividly see Pissarro through the articulacy of a guide and the push of their own fingers against the ingenious reply of raised paint reproductions.

And yet, despite these profoundly poignant human moments, one universal truth emerges; that these living breathing people are a humble supporting cast for the glorious ghosts on the walls. Wiseman’s deft incorporation of the gallery’s ambient noise and his disrespect for the bookends of conversation heighten this energy until the human stories and interventions merge into so much white noise. The painstaking restorations witnessed throughout are made mockery and marvelous when we discover that they are applied over a layer of varnish so future generations with their grand technologies may eradicate them in one swipe. This serves as perfect metaphor for the feature as a whole. It shows us the pomposity, hierarchy and swagger of the institution then humbles it before the art it hosts.

The film is long, loosely structured and uninterrupted by music or drama. Instead movement after lyrical movement is layered until the gallery’s indescribable atmosphere becomes a tangible presence in the room. On Wednesday night a vigil for those lost in the Charlie Hebdo attack huddled beneath the building’s impassive gaze. The board may be determined to keep the ‘lowest common denominator’ out but, as on the gallery’s walls, the joys and sorrows of mankind will continue to dance at her feet. National Gallery concludes with a tribute ballet (scored by William Byrd) of angular gestures expressed on demi-pointe. Yet ballet aficionado Wiseman ends as he began, turning from the stunning pas de deux to glance across The Masters, and close on a Rembrandt self-portrait. Ensuring that only the faces in the frames remain framed in our minds.