The gray tones in Julie Mehretu’s paintings pack more of a punch than most artists’ entire palettes. They’re never idle or neutral; often they crackle with heat. Even when relegated to the background they seem like the raw material from which color is made. When Mehretu called a series of paintings “Grey Area,” the title didn’t suggest ambiguity so much as coiled potential.

Selections from “Grey Area” appear in “Julie Mehretu,” a mid-career survey at LACMA that reconfirms the artist as a rare talent. Mehretu is one of the few painters who can talk the big conceptual talk of systems and globalization without neglecting her craft. Ethiopia-born, Michigan-raised, and RISD-educated, she makes images that feel ambitious not simply for their size (although some are as big as a swimming pool) but also for their nuanced structure and dense, sedimentary layers. By 1997, the year she earned her master’s in fine arts, Mehretu already had an extensive tool kit of forms: whorls, arrows, licks of color. The pieces were there; the challenge was setting them in motion.