Whether delicately hushed or eye-poppingly intense, Dan Christensen’s abstractions unfailingly offer an ever-changing mix of incandescent colors, looping lines, giant dots, frothy patches, and loose calligraphies.

Christensen, who died in 2007, belonged to a group of painters who persisted in the legacy of postwar abstraction long after Conceptualism, video art, and other currents gained dominance in the 1960s and ’70s. And though the New York–based artist attracted the support of important critics, Clement Greenberg among them, and his paintings have joined the collections of more than thirty