You have to be an egomaniac to keep your most precious possession hidden. And so was the speaker in “My Last Duchess,” the dramatic monologue by Robert Browning.
He alone unveils a portrait of the wife he killed, “for none puts by / The curtain I have drawn for you, but I.” He reveals more than he intends, but such are madness and poetry. In real life, patrons of Renaissance art had other motives than egomania: they were out to share the artist’s vision and their own. 
They were putting on a show, and the curtain, if any, was just part of the act. The Met, though, sees only reticence and ownership. With “Hidden Faces: Covered Portraits of the Renaissance,” it calls up the devices that kept Renaissance portraits hidden, if not exactly under lock and key, from some of the period’s finest artists. It could be literally the obverse of textbook histories and modern museum displays, but were these faces truly under cover? And what, then, were they doing in paint? You may well wonder what the show is hiding, through July 7—and I work this together with an earlier report on Renaissance Bruges as a longer review and my latest upload.
From the very start of “Hidden Faces,” you might wonder what all the fuss is about. Religious art thrived on triptychs with wings that spoke of adoration of the central scene—wings that often folded shut. The donor portraits in the Ghent Altarpiece by Hubert and Jan van Eyck occupy just two of twenty panels, both on the outside. Rapt in their piety and vision, they give way to that glorious vision as the wings open. You will not see that painting or its kind here. Instead, the Met opens with a single panel, a portrait of nobility and restraint by Rogier van der Weyden.
It does, though, have a heraldic device on its back, and it may well have hung from a chain, back facing front, until the man choose to swing it around. Here and in other works, heraldry, text, or the illusion of an official document attests to fidelity and ancestry. Do they sound more like obstacles than invitations to see more? One Latin inscription reads Noli Me Tangere, or “do not touch”—and the risen Christ’s words to Mary Magdalene could apply to the viewer and the painting as well. A panel could also slide over a portrait, an open and shut case. As for curtains, an illuminated manuscript depicts one, drawn aside from a Madonna and Child.
As constructions grew more sophisticated, so did the mask. With Hans Memling, heraldry gives way to still life. The leaves of the first have become a finely glazed vase holding flowers, sharing its warmth and illusion with the man’s shadow and beard stubble. Still others present an allegory, often as not more vivid than the portrait. With Lorenzo Lotto in Venice, petals shower down on Virtue, a woman, while Vice lurks, sinister but ineffectual, behind a tree. In a rare grisaille, or monochrome, Titian places Cupid beside the wheel of fortune, in command of fortune or its subject. It is chastening to think that painting like his on canvas, rather than panels, caught on as a natural cover.
Do not rejoice too soon at your own fortune. Most of these coverings are lost to time, and the curator, Alison Manges Nogueira, must settle for second-rate artists or clever recreations. On video, wood can still slide open and shut. 
Too much else is left to medallions or to the backwaters of Germany and the southern Netherlands. Jacometto Veneziano learned from Antonello da Messina, perhaps the first in Italy to experiment in oils. His portraits are lifeless all the same.
Just as scarce is an appreciation of art’s motives. Sure, the Met concedes, covering could protect a work from the elements, and smaller works in lockets had the advantage of portability. One could keep them close to one’s heart. Otherwise, the emphasis is on privacy, privilege, and hiding. It might do better to think of publicity and revelation. In that illuminated manuscript, nuns draw aside the curtain for a vision to refresh a weary traveler.
A curtain speaks not only of masking, but also of theater, and the whole point of a folding altarpiece is vision. It could be celebrating itself as a vision onto real and imagined worlds. This was after all the Renaissance with its greater realism and self-reflection. As with an altarpiece, that vision could take place in a public place, too, a cathedral. Lucas Cranach made his miniatures of Martin Luther and his wife, a former nun, not just to please them, but to spread the word to those still outraged at their marriage. But then, as another Latin inscription has it, “to each his own mask.”
Read more, now in a feature-length article on this site.