Stephen Kaltenbach, Humilis, Burnished Steel & Unknown Contents, Unique Time Capsule, 4 x 4 x 12", 1970 - Present Credit: Courtesy Bert Green Fine Art

In the late 1960s, Stephen Kaltenbach was among a group of New York-based artists who founded the movement eventually called conceptualism. It became widely influential, in part because its parameters were so liquid: in its antimuseum, anticommodity stance, conceptualism privileged ideas over objects, words over images, communal sharing over individual ownership. It was a perfect fit for the era’s burgeoning counterculture.

The new exhibit at Bert Green Fine Art surveys Kaltenbach’s work since 1965. The artist’s roots in minimalism are evident; everything is pared down to essentials, offering little to distract the viewer from grappling with the ideas that the work presents. The effect is at once austere and playful.

For example, the impression print Lips (Kiss) (2005) has its genesis in the rubber stamp Kaltenbach devised early in his career to add graffiti to public advertising posters. Nothing Is Revealed (2005) is a stenciled message spray-painted on paper that challenges passive consumers. Esteemed Visitant (1970s), a steel cube with a pinhole in the center, is a camera obscura: the image of the onlooker is projected into the interior, which means that viewers get their heads inside the box both literally and figuratively.

Two of the works are premieres, installations that predate the artist’s celebrated 1967 “room constructions.” Both Shadow Wall (1965) and Diminished Corner, State II (1965) emphasize the tensions between light and shadow, between clarity and opacity. This is art in its bare bones; if you could translate it into audio terms, it would be like the humming along a tight wire. In a recent interview, Kaltenbach told me, “The less the artwork covers the concept, the stronger it is, and the better I like it.”

Most intriguing are the expressions of the artist’s spiritual leanings, which combine self-referential elements and allusions to mortality and transcendence. The bronze plaque Art Works (1968), were it set in pavement like the New York sidewalk plaques that inspired it, would be obscured over time, its maker forgotten with its message. And mystery and the finite are central to Kaltenbach’s time capsules, such as Humilis (1970), a burnished steel cylinder whose contents are unknown, and whose inscription teasingly reads, “Please open this capsule before deaccessing it.” Following those instructions, of course, would make resale impossible.