There are many difficulties in the act of collaboration. To assert one's creative interest and expression and simultaneously share the stage with another's agenda is a careful balancing act. Collaborations, at best, can incite artists to move beyond their niche, to grow and transform; at worst they can be a struggle of wills and power, or a polite tiptoe that results in staid, safe versions of the artist's own work. 'From Johannesburg to New York', a collaborative exhibition by Samson Mnisi and Cannon Hersey currently on exhibition at Museum of Contemporary African Diaspora Art (MoCADA) in Brooklyn, New York, leans toward the latter.

The show, divided into three distinct sections or rooms, covers the artists' joint practice, as well as a selection of individual works from each. The first, a black, dramatically lit room, displays the most recent offerings of the alliance. Working with Brazilian Sisal carpets as canvases, each artist asserts his process - Mnisi with brightly coloured and expressive painting, Hersey with lightboxed photographic images cut into the woven surface. Along with these signature elements, fragments of cloth from far-reaching lands are collaged on to the 'canvas', partially illuminated by the lightbox. Tibetan prayer flags, Indian printed fabric, sections of a Shanghai Tang jacket and Malaysian silk all work their way into the pieces.

Seen in conjunction with Hersey's photographic material (taken during his worldwide travels) and Mnisi's ritualised markings, the effect is that of a patchwork of culture and aesthetics. It is difficult to see past the swirl of cultural messages to the intention of the pieces. They seem to only scratch the surface, to reference multiple complex issues of the iconic versus the ordinary, the mystic versus the monopolised, all regretfully without truly exploring the content.

The pieces were commissioned by MoCADA in New York, created in Brazil and exhibited at the Sao Paulo Bienniale 2008. This may account for the overreaching diversity of the material. Both artists seem to draw from their immediate surroundings in their individual practice (Hersey in his representation of his global exploration; Mnisi in his utilising of his family tradition of Sangoma ritual practice), and the addition of the Brazilian influence becomes a little too over-messaged.

The second room shows Hersey's photographs delicately marked and adorned by Mnisi. These are older collaborations, made in 1999 - 2000. Here, the subjects of the imagery are localised - Hersey has captured scenes of South African street-life in the late 90s. A boy runs down a township road; a smiling man rides in the back of a speeding bakkie; the façade and surrounding activity of a rural Chicken Licken restaurant. As the catalogue attests, Hersey sees the South African landscape as an outsider, intrigued by, and critical of the visual surface. Mnisi's playful symbols seem to engage with and enliven the images. The mounting of each photograph on South African burlap is an interesting touch, bringing further aesthetic and locative texture to the images.

Yet, as with the more recent collaborative work, a sense of cautiousness is all-pervasive. Neither artist seems to take chances, and the result is unsatisfying.

This room also displays prints by Hersey, duplicate photo-etchings in varying flesh tones. One in particular, a heavily layered graffiti wall, ranges from a rich burnt wood colour to oatmeal pink. Certain aspects of the image reveal themselves in each shade's rendition, like a shifting perspective. The prints are subtly rendered and evocative.

The final room shows only Mnisi's work: two sculptural canvases and a large monoprint. The canvases fit together like puzzle pieces; their angular forms contrary, but complementary to the expressive painted surface. Scratches, arrows and ritual characters - an intricately rendered thought pattern - break the flat blue plane of the monoprint. The markings seem decipherable, like a carefully plotted route or a concealed message. This mystic quality to Mnisi's style is enigmatic without becoming alienating, an invitation for personal interpretation without judgement or possibility of fault.

This encouragement to engage is well suited to the show's location, in this museum in the heart of downtown Brooklyn. A definitive hotbed for the celebration of Africanness in New York, the museum and its visitors are more than receptive to Mnisi's ritualistic expression. The exhibition's opening was a packed, lively affair; the crowd eager to absorb and discuss the work.

The enthusiasm was impressive, but felt almost cursory. When integrated with each other, both artists' work lose their subtler qualities and become straightforward representations of their different approaches. Hersey becomes the foreign documenter, self-conscious of his otherness and glorifying his subjects while Mnisi fills the role of the African mystic, his work based on signals, exotic patterns and ritual processes. Their collaboration feels unresolved. 'From Johannesburg to New York' becomes a comment on the polarities between these locations, rather than offering a tangible or useful connection between them.

Opens: January 29
Closes: May 17

MoCADA
James E. Davis Art Building, 80 Hanson Place, Brooklyn, NY
www.mocada.org