The title Red April references the assassination of Dr. Martin Luther King, Jr. (April 4, 1968), and the riots that followed in Washington, D.C., where Sam Gilliam resided.
Gilliam painted Red April by pouring and splattering acrylic pigments (some thinned-out, some thick and intense) onto a raw canvas he placed on the floor. Gilliam folded the canvas like an accordion and let the paint dry for a while. He intended for some of the pigment to remain wet so that when he unfolded the canvas, it would pull off and adhere to the canvas on top of it. Gilliam then stretched the canvas on beveled stretchers, so it would appear to be coming out of the wall.