When not converging on literally nothing, his pictorial schemes address objects that are either remote, like the moon, or obdurate, like the battered oak. Human figures intercept our gaze and transmit it into ineffable distance. The pictures don't give; they take. Something is drawn out of us with a harrowing effect, which Friedrich's use of color nudges toward intoxication. What at first seem to be mere tints in a tonal range combust into distinctly scented, disembodied hues: drenching purples and scratchy russets, plum.