GHENT (NYT NEWS SERVICE).- God is in the details, they assure you; but some art is so jam-packed with details, each hair so fine, each fold so painstaking, that it surpasses even the divine. Nearly six centuries ago here, the painter Jan van Eyck used a brand-new technology — oil paint — to pioneer an art of such precision that it almost negated its religious function, and went past inspiring prayer to become something eternal itself. Still today, for secular audiences, his diamond-hard paintings can appear to come from another world.

Some artists inspire you. Van Eyck leaves you stupefied. And “Van Eyck: An Optical Revolution,” the largest exhibition ever of painting by this superman of the early Renaissance, which now fills the Museum of Fine Arts here, is a perpetual stupefaction machine.

Van Eyck was born in 1390 in the east of what is now Belgium, and he worked and died in booming Bruges. But Ghent, the Flemish university town, is where you’ll find his greatest achievement: the “Adoration of the Mystic Lamb” altarpiece he painted with his brother Hubert. Over the last decade conservators here have been restoring its two dozen panels — whose gemlike depictions of Jesus and Mary, Adam and Eve, and a curiously humanoid sheep — have inspired pilgrimages, adorations, riots and at least six thefts. Napoleon stole several panels, and the Nazis took the whole thing; the Monuments Men returned the altarpiece to St. Bavo’s Cathedral in 1945, but one of van Eyck’s panels is still missing.

“Once in a lifetime,” a phrase I usually disdain as a marketer’s wheeze, truly applies to this giant show. For this occasion only, the altarpiece’s eight recently restored outer panels — including a pellucid Annunciation featuring Mary and Gabriel in Belgian-chic gray — have left the cathedral and are being displayed as independent paintings, which means you can get closer than ever before. At the end of April, they’ll rejoin their interior partners at St. Bavo’s for good.

Besides the altarpiece, only 22 autograph paintings by van Eyck survive, and 12 of them have made the trip back here, as have another nine attributed to van Eyck and his workshop assistants. Add in tapestries, marble statues, illuminated manuscripts and paintings by fellow Flemings such as Petrus Christus and Italian contemporaries like Fra Angelico, and you have a blockbuster of celestial proportions.

Ghent’s Museum of Fine Arts (known by its Dutch abbreviation MSK) has smartly cleared out an entire wing of its collection galleries to make space for “An Optical Revolution,” and contextualizes the changes wrought by van Eyck’s ultrameticulous art across six whole introductory rooms. The Burgundian Netherlands was one of Europe’s most urbanized areas in the early 15th century. As the region got richer, and as the court partied from Brussels to Ghent to Bruges, local notables competed to commission luxurious and learned works of art — including, for the first time, panel paintings.

Van Eyck (and his brother) saw Burgundy booming from afar, and this immigrant artist soon won the trust of Philip the Good, the duke of Burgundy, for whom he served as a court painter, confidant and even spy. From this artistic and cultural epicenter, van Eyck developed a new painting style, which saw the flat signs of Gothic painting give way to exquisite illusions of bodies in real spaces. He discovered that, by varying how crisply or hazily he painted a tree or building, he could reproduce on a flush plank of poplar the depths of a Flemish countryside or a palace interior.

He used light effects to simulate buttery flesh that, even at small scale, made saints appear like real human beings. Consider his “Madonna at the Fountain,” in which the beatific Mary hovers in three dimensions before a brocaded carpet, held aloft by two rainbow-winged angels. On its frame you can read the artist’s trademark, brilliantly arrogant catchphrase: “Als Ich Kan,” or “As well as I can.” By which you’re meant to understand: this well, as well as God’s own creation.

What empowered van Eyck’s out-of-nowhere naturalism — the incredible sense, as the art historian Ernst Gombrich would write, that he was holding “the mirror to reality in all its details”? New scientific insights, for a start, into optics, reflections and focal points. Hand-eye coordination that would make an Olympic archer jealous. Above all, it was the innovation of oil paint, which dries more slowly than tempera, and which can be blended wet-on-wet to produce contours, shadows and highlights.

Oil paint did to 15th-century Flanders what camera phones did to our time: It set off an image explosion. Portraiture became more robust and vivid; you could spend a whole day gazing at van Eyck’s picture of the goldsmith Jan de Leeuw, on loan here from Vienna’s Kunsthistorisches Museum, who sits at a slight angle and appears to loom out of the frame.

And oil paint, above all in the van Eyck brothers’ altarpiece, birthed a new religious art with such exactitude that believers could look past this world to the world beyond. In the altarpiece panel depicting the nude Adam, moved to the MSK, you can see a dusting of individual black hairs on his milk-white thighs and calves, and even his toenails have been meticulously curved. On Gabriel’s wings you can make out every last feather, gently gradating from green to gold to grapefruit pink.

The Virgin annunciate, usually overshadowed by the altarpiece’s more colorful panels, appears here as a stand-alone masterpiece. Her face is as pearlescent as an oyster shell. Her soft hair has been rendered with smoky, blurry brush strokes that anticipate Leonardo’s mastery of sfumato by decades. I’d seen it once before at a distance at the MSK, where the restorations took place. But this panel of Mary appeared to me like a new van Eyck: like one of the most beautiful works of art I have ever seen.

It’s a wild privilege to see these panels in fresh spaces and new contexts, but the experience at the MSK is a mixed bag. To accommodate van Eyck’s many fans, the museum is selling timed tickets, and staying open until 11 p.m. three nights a week. Even on a fully subscribed Saturday afternoon, the crowds never got too thick. You can look more closely and comfortably at these panels than other recent European blockbusters with timed tickets allowed, such as the Louvre’s busy Leonardo retrospective, or the even more jammed show of Frida Kahlo’s clothing at the Victoria & Albert Museum.

But don’t expect Edenic silence. The MSK provides visitors with audio guides that must be passed in front of motion detectors stationed next to each painting, emitting a beep with every swipe. They make the galleries sound like a Kmart checkout line, and pose such an infernal distraction you may want to bring earplugs.

Concentration doesn’t come easier at St. Bavo’s Cathedral, in Ghent’s historical center, where the interior panels of the altarpiece are on display. They’re shown in a cramped little room, and although the church forbids both speaking and photography inside, that doesn’t help when you hear the roar of dozens of hand-held audio guides. (The cathedral is opening a new interpretation center this autumn, and I have one request: please, audio guides with in-ear headphones.)

Under these conditions, and with van Eyck’s panels more than 5 feet away behind thick glass, I struggled to form a definitive opinion on their restoration — especially regarding the face of the Lamb of God, which in January launched a thousand memes more worthy of ruminants than children of Adam. The altarpiece does appear brighter and crisper than it did on my last visit to Ghent. Mary glistens, the angels trill. But it’s hard to appreciate the altarpiece, here, as anything but a bucket-list jewel. It made me think, for better and worse, of my iPhone’s screen, which emits light through each pixel.

If van Eyck’s innovations are hard to see in the cathedral, all the more reason to grab the chance to see the outer panels at the MSK. Consider this, however: We see more images in a month than the worshippers of 15th-century Flanders saw in a lifetime. And even we, in our muddle of memes, feel something like the awe they must have experienced standing before these 600-year-old paintings, where human invention stretches toward the sacred.

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