The Leslie-Lohman Museum of Gay and Lesbian Art, which has a lively show called “Found: Queer Archaeology; Queer Abstraction” on through the fall, is itself an archaeological project of many layers. The museum reopened last spring after renovations, but has existed in New York, in one form or another, for nearly 50 years.

It originated in a SoHo loft shared by two men, Charles W. Leslie and Fritz Lohman (1922-2010), life partners and collectors of homoerotic painting, drawing and photography. In the summer of 1969, they opened their home as a weekend art salon and were astonished when hundreds of people showed up. It turned out that the type of art they loved, “unambiguously gay” and shunned by conventional museums, had a zealous following.

Soon afterward, the couple opened a commercial gallery in SoHo. But in the 1980s, their focus turned from promotion to preservation. AIDS was devastating the gay art community. Entire careers were disappearing as artists lost homes or died and had work trashed.