In the mid-19th century, the poet and critic Charles Baudelaire famously castigated sculpture for being at once too literal and too elusive. "Though as brutal and positive as nature herself," he wrote, "[sculpture] has at the same time a certain vagueness and ambiguity, because it exhibits too many surfaces at once." Given these inherent flaws, for Baudelaire, all sculpture was but a primitive stage in the development of art toward painting. For Mark Grotjahn, this sculptural "primitivism" has of late become particularly productive.

Over the last decade, Grotjahn has been making cardboard sculptures alongside his well-known paintings, in what was (until now) a studio exercise. He begins with a readymade box and then rips and gouges its surface, sometimes attaching appendages fashioned from cardboard tubes or other ordinary items. For this exhibition, Grotjahn presented 27 painted bronze casts of these assemblages, which he calls "Masks." Crude visages have appeared in his paintings over the years, most recently in the "Face" series shown at New York's Anton Kern gallery in 2009. The classification of these sculptures as masks, however, signals a subtle shift. The term describes the works' rudimentary facial features while also indicating operations of deception and concealment, here occurring between cardboard, bronze and painted surface.

In the larger of two galleries, 18 "Masks," each 2 to 3 feet high, were displayed on white pedestals and on the wall. The effect was confrontational and theatrical, proffering the full rainbow of Grotjahn's electric palette. The lumpy and provisional appearance of the forms belied their material existence as bronze casts, which retain the impoverished look of their first state: cardboard boxes with punctured eyes and ripped mouths. Some have an orifice where the nose would be, while others have nasal protrusions, which in the case of Untitled (Call Me Jackson Washed Black Brown Nose Morgan Mask M21.d), 2012, is extended to comic (and phallic) ends.

The paint is applied with fingers and possesses an expressionist tactility (the "Jackson" in the above title refers to none other than Pollock), but the lurid colors also have a kitsch aspect. The rich, almost velvety texture of the titular colors in Untitled (Blue and Purple Flames Picasso Mask M8.f), 2011, is flecked with fiery orange-red underpainting. Sometimes the paint is so thickly applied-as in the caked-on layers of white, rose and blue in Untitled (Scrapped and Lost FK2 Mask M8.c), 2012-that it appears to weigh down the apparently buckling surfaces. This visual cause and effect, however, is just an illusion.

In the smaller, second gallery, nine "Masks" were lined up single-file down the center of the space with their "faces" turned to one wall. This installation highlighted the back of the boxes, which are sometimes open to reveal empty, painted interiors. Where Grotjahn's well-known "Butterfly" paintings use multiple vanishing points to play with the construction of perspective and the insistently frontal structure of painting, in these works, every visible surface becomes its own canvas, including the backs and exposed insides of the bronze forms.

Photo: Mark Grotjahn: Untitled (Call Me Jackson Washed Black Brown Nose Morgan Mask M21.d), 2012, painted bronze, 33¾ by 29½ by 32 inches; at Gagosian.