New light on Old Masters

You love Vermeer's Girl With a Pearl Earring. But what do you really know about it? What is it — who is it — that you are really seeing there, beyond the surface of the paint?

David Stork knows. He has been through Vermeer's looking glass and seen the other side. He has floated beside the painting's beauty and he has ridden its light, Tinker Bell-style, as it flashes on her pearl then bounces from cheek to nose to liquid eyes.

Stork, 55, is a physicist and he has used optical science and a good bit of computing power to make a virtual 3-D copy of the world that Vermeer gave us in two dimensions.

In that world, the painter's “girl'' gets a kind of Second Life form, which Stork has used to solve some of the painting's puzzles, such as whether Vermeer could have painted his subject from life and how he might have lighted her if he did.

“When people look and say, ‘Look how impressive his lighting is?' they don't know how impressive,'' Stork says.

His techniques do for art historians, he says, “just what a microscope does for biologists. We can now reveal things in art that we didn't see before.''

Or at least that is what he proved in a lecture he gave recently at the National Gallery of Art.

Stork talked about how his knowledge of vision, optics and computers — an entire 30-page CV's worth of scientific achievements — has let him look into Vermeer's light and discover just how closely it matches reality.

It has let him step into Caravaggio's great Calling of Saint Matthew and find out that the daylight that seems to shine into its tavern isn't natural at all: It could only have come from some kind of artificial source in Caravaggio's studio.

Most recently, Stork's science has allowed him to take on Las Meninas by Velazquez, possibly the greatest picture ever made, and one of the most befuddling.

By translating Velazquez's painted scene into a virtual world, Stork has been able to untangle some of its knots: He has figured out what kind of space the picture shows and exactly who is doing what in it.

In a lecture hall, Stork's energy is endearing and infectious and he knows how to dumb down his subject when it is called for.

His PhD in physics is from the University of Maryland, he has 37 patents, a Silicon Valley job directing research on digital imaging for Ricoh Innovations and a teaching position at Stanford.

The day before his talk at the gallery, Stork was at Darpa, the Defence Department research group in Arlington, Virginia, briefing military's eggheads on “securely outsourcing audio and video analytics''.

None of which has helped him break into the world of art history.

Over a Sunday lunch at the Phillips Collection — a favourite spot — Stork was frustrated that only a handful of art historians seemed to care or even know about his work on pictures.

That work started when Stork encountered a radical claim by celebrity painter David Hockney that had received huge media attention.

In his 2001 book Secret Knowledge, Hockney asserted that the great masters of Renaissance art had set up their subjects in front of curved mirrors or lenses, which then projected images that the artists traced their pictures from.

That, Hockney claimed, is what accounts for the huge increase in realism that hits Western art in the years after 1400.

Stork says he received a last-minute invitation to a conference on Hockney's theory, which he had barely heard of, as one of the few people who could debate the science involved.

He had started out thinking the claims looked interesting but then watched as the evidence collapsed “like a house of cards'' under his physicist's touch.

Which, he says, is when his work on art “really took off'' — for him, if not for most art experts.

Although scholars have been happy to see Stork use science to bring about the demise of Hockney's theory, his work has simply felt like confirmation of something they had always insisted on, for all sorts of cogent historical reasons.

As for Stork's non-Hockney discoveries, the problem is that, as fascinating as they are, it hasn't always been clear what kind of profound insights they can bring to art.

Stork's microscope analogy is all very well but even the most powerful microscope isn't any good unless you are pointing it at the right things, to solve the right problems and letting the right people look through it.

Take Stork's paper on the light in Girl With a Pearl Earring, published, like many of his findings, in an esoteric scientific journal.

It proves the highlights on her pearl, the cast shadow of her nose and the soft shading on her jaw give independent, cross-verifiable confirmation of the picture's light.

But reading that paper, even the most brilliant art historian might need some extra coffee to follow Stork and his team as they set out to explain their theory in scientific language.

Even without the language problem, it doesn't get us very far just to confirm that (or even why) the light in Vermeer's painting seems astoundingly real: That is a cliché about the picture.

As far as the art world is concerned, the real insight in Stork's paper is buried in a line in the thick of a discussion of computer modelling: “We assume Vermeer executed the portrait from a live model and sought to render reasonably faithfully what he saw.''

Actually, that assumption isn't obvious at all. Art historians know surprisingly little about how the Old Masters really worked: how much was drawn or painted on the spot in front of a live model, how much was freely altered afterwards and how much in a picture was entirely made up.

The most important thing about Stork's virtual-world version of the Girl With a Pearl Earring is that it can exist at all: that Vermeer's picture is so perfectly consistent in its every detail that a computer can use it as the basis for building an equally consistent 3-D world, complete with lighting.

That seems pretty good evidence that there was more observation than imagination in the making of the picture.

“I understand the constructed nature of art — that artists are not photographers,'' Stork says. “All that our techniques can do is point out when the artists were consistent and realistic or not.''

But what is not clear — or has yet to be proven — is whether computer analysis could ever tell the difference between a picture that science registers as completely realistic because it is done from life and one that a computer reads as realistic just because a painter has got the skills to fake it perfectly.

David Stone, an art historian from the University of Delaware, has agreed to work with the scientist on a paper that will set out the full art-historical potential — and, perhaps, the limitations — of the computer analysis.

“I'm just at the beginning of understanding the implications of Stork's work,'' Stone says. It is about “getting at the decisions that artists make'' — by finding new ways to look at the pictures they painted.

Take Stork's work on Las Meninas. Velazquez's great puzzle-picture shows the artist himself painting a portrait of the king and queen of Spain, whom we glimpse only through their reflection in a mirror on the back wall of the scene.

(We can't see the royals themselves because Velazquez seems to render the whole setting as though it is being viewed through their eyes.)

What has never been clear is whether we are supposed to imagine that the mirror is reflecting the actual royals or whether what we are seeing in it is a reflection of the picture Velazquez is painting of them.

Stork has resolved the issue by building a computer model of the painting that lets us view its scene from any angle.

What we discover is that the only way the layout of the painting works is if it is the royal portrait, rather than the royal couple, that has been caught in that reflection.

“We're just a tool that will help art historians,'' Stork says. But that doesn't mean he suffers from false modesty: “I think we're making a difference and will make an even greater difference in the future — especially now that Hockney is out of the way.''