Suzanne Jackson was drawing two lines by 1968: One she traced over and over in watercolors and oils and strange new acrylics, of wingspans and the receding landscapes of her adolescence; the other was a limit, drawing a boundary against a relentless decade and the demands of her contemporaries. Her lines intersected at Gallery 32. Sectioning off half of her live-work studio in the Spanish-style Granada Buildings in MacArthur Park, Jackson handed the floor over to her classmates and teachers from the then-nearby Chouinard Art Institute (which has since merged with CalArts) and Otis College of Art and Design, including David Hammons and Charles White. She also hosted fundraisers for the Black Arts Council, Watts Tower Arts Center, and Black Panther Party, as well as “Sapphire Show” (1970), the first survey of black women artists in Los Angeles. Evidence of this history is on view in the foyer of O-Town House, a new gallery located in the Granada Buildings, just a floor above and a half-century behind the original Gallery 32. Folds of handwritten invitations, curling photographs, price lists, exhibition announcements, and contact sheets fill a line of vitrines, laying out an ephemeral context for the exhibition of Jackson’s works from …