The question that most comes to mind when reading Carol Vogel‘s story on the rediscovery of the Met’s Velázquez portrait is not that the work is indeed by the Spanish master. It entered the museum as a Velazquez. What’s remarkable is the way the doubts built up over time until they extinguished the attribution:

Experts had reason to doubt the authorship: Decades of varnish had discolored the canvas so much that its palette looked far darker than that of other paintings by Velázquez. The painting had been heavily restored and cleaned in the 1920s and revarnished in 1953 and again in 1965. In 1960s a leading scholar demoted it to the workshop of Velázquez and by 1979, the museum had downgraded the painting as well.

Still, when the museum recently started to catalog the Spanish paintings in its collection, Mr. Christensen asked Michael Gallagher, chief of the Met’s paintings conservation department, to take another look. He ended up not only studying the painting but also carefully cleaning and conserving it. As details like the individual brushstrokes of a collar emerged, he concluded that Mr. Christiansen’s instincts were on target. Buried beneath decades of yellowed varnish and poor retouching were all the marks of Velázquez’s hand.

Convinced that the picture was indeed by the master, he and Mr. Christiansen showed it to Jonathan Brown, this country’s leading Velázquez expert, who agreed.

“One glance was all it took,” Mr. Brown said, adding later, “The picture had been under my nose all my life. It’s a fantastic discovery. It suddenly emerges Cinderella-like.” […]

To a conservator, Mr. Gallagher said, the prospect of working on the painting was daunting. The canvas was so dark, “it was like looking at the bottom of a murky pond.” The synthetic varnish had deteriorated, as had some of the layers painted over the original.

He began gingerly, performing a test on a tiny portion, removing varnish with an organic solvent. The murky green background suddenly became gray after it was cleaned. The densely painted face showed a vibrancy that had been obscured as had the small number of brushstrokes needed to evoke the man’s detailed white collar. His eyes turned out to be haunting and his brow bushy.

An Old Master Emerges from Grime (New York Times)