There’s something unsettling about the beauty of Frank Ammerlaan’s paintings. Their surfaces look almost like pools of oil suspended on water: Hallucinatory rainbow colors form voluptuous clouds that are delicate, all-encompassing, sublime. Yet their obvious dependence on chance raises the question of what their beauty means. To make the works in his recent untitled series (all 2012), for example, Ammerlaan, who graduated from London’s Royal College of Art last year, first blackens his canvases with acrylic paint, then deposits them in a bath of water with an undisclosed mixture of chemicals,