ST. LOUIS — Color is powerful. It can stop traffic, sell a product, make art sing. It’s also political. The color of your skin can lock you into a history; end your life. It did so in the case of Michael Brown, the unarmed African-American killed by police bullets in the St. Louis suburb of Ferguson three years ago this week.

Racially, the city has been on the alert since. Tensions surfaced last September in protests against the Contemporary Art Museum here around a show of work by a white artist, Kelley Walker, that included images of black bodies smeared with chocolate and rainbow-colored toothpaste. A large group exhibition this summer called “Blue Black” at the Pulitzer Arts Foundation, mere steps from the contemporary museum, is entirely about color, and might have seemed ripe for controversy. Yet, as far as I know, it has not caused a stir.