Martin Wong, Medici of the Aerosol Art Set

Martin Wong got in with the graffiti writers in the early 1980s at Pearl Paint, the long-gone Canal Street art supply store, where he had a job in the canvas department. Wong would slip them markers or cans of spray paint or sell them supplies on deep, unsanctioned discounts, which endeared him to artists at crucial moments of their careers. The painter Lee Quiñones recalls Wong writing out $20 invoices for portrait-quality linens priced at $400.

Wong soon began buying Quiñones’s work and that of like-minded painters like Daze, Sharp and A-One — artists who were moving away from bombing trains with graffiti and developing studio practices. In so doing, he nurtured their development and became a constructive patron: a Cosimo de’ Medici of the aerosol set. His collection is highlighted in “Above Ground,” a small but essential exhibition at the Museum of the City of New York.

By 1994 Wong had amassed upward of 300 artworks and other media, all of which he donated to the museum that year. As interest in both the modern graffiti movement and its diasporic reverberations has grown, Wong’s conviction has proved consequential, his collection functioning as a repository. Pieces from it have been lent to major institutional surveys, like “Writing the Future: Basquiat and the Hip-Hop Generation” at the MFA Boston and “Art in the Streets” at the Museum of Contemporary Art in Los Angeles, shows that have deepened scholarship of this previously maligned and misunderstood period.

Outsiders had been hot on graffiti at the same time as Wong was, but none had a more ardent or abiding interest. He recognized what was an irreducible form of American expressionism and its importance in the history of New York, even as much of the city was hostile toward it.

Wong was 32 when he arrived in New York from San Francisco in 1978 and was drawn immediately to the baroque layers of tags spreading across the city’s surfaces. Wong’s own art, an urban realism that synthesized documentarian detail and romantic devotion (no artist lavished more attention on bricks), had little technical overlap but shared a sympathetic kinship. His paintings referred to the street, and so invariably referred to graffiti too. He reproduced the Lower East Side’s tagged handball courts and crumbling redbrick tenement buildings as oppressive but softened, bathed in a dingy cast that can feel like ecstatic reverie.