Red Petals is among the first paintings in which Gilliam poured paint onto an unprimed and unstretched canvas, folded the canvas onto itself, suspended it, and left the paint to settle overnight, subject to the force of gravity. The next day he would sponge, daub, splatter, fold, or roll the canvas. In the case of Red Petals, he also restretched the canvas. The emotional intensity and expressionistic force of Red Petals partly derives from this careful manipulation and the tension between chance and control.
In Red Petals, each nucleus of cadmium red, infused with highlights of hot coral, bleeds into black-violet stains that flow back into the cadmium before ending in feathered veils of green and yellow. Cobalt blue breaks through from beneath the reds, framed on the left by a strip of violet and yellow that recalls batik fabric. On the lower edge of the composition, splatterings of yellow and red paint erupt from the unprimed canvas, balanced on the upper edge by cadmium-red, orange, and coral tones.
Although Gilliam had experimented with spontaneous methods, including staining, Red Petals was the first in which he entirely abandoned sharp edges. Gilliam's improvisational technique and its emotive influence on the viewer have often been compared to the abstract quality of free-form jazz compositions. Although Gilliam acknowledges this influence, in particular the chromatic tonalities of John Coltrane, he cautions against isolating this quality of his work as merely an outgrowth of his African-American heritage.
Affiliated with Washington Color School artists Morris Louis, Kenneth Noland, and Thomas Downing by region and to a certain extent technique, Gilliam’s gestural handling of paint is also associated with the color field paintings of Helen Frankenthaler and Hans Hofmann. Like other local artists of his generation, Gilliam used The Phillips Collection for study, admiring in particular the works of Rothko, MacIver, and Tack.