Series 41. Two Color Twist, Yellow and Violet. Three Colour Twist, Red, Green and Blue.

The exhibition catalog highlights a fundamental principle of this research: when visual elements are extremely small or closely spaced, they merge into a single perceptual tone. This phenomenon of “optical mixing,” already central to Georges Seurat’s pointillist technique, produces effects of vibration, luminosity, and even pulsation. The eye is thus “bombarded with pure energy,” sometimes generating unexpected color impressions (pale pinks, golds, or blues) even though the surface may be devoid of actual color.

This perceptual logic is essential to understanding Riley’s evolution. Her transition from black-and-white to color was not a break with the past, but rather a deepening of the optical phenomena she had already explored. Her in-depth study of Seurat was decisive. Her study of Le Pont de Courbevoie in 1959 enabled her to assimilate the principles of Divisionism and “chromo-luminarism,” a concept favored by Seurat himself. This principle is fully at work here: complementary contrasts intensify the visual vibrations, while more complex combinations enrich the perceptual rhythm.

This gouache on paper is part of a series in which Riley explores the dynamic interplay of colors through sinuous, rhythmic bands. The composition is based on chromatic alternations (yellow/purple and red/green/blue) arranged in a twisted structure. The work is built on this tension between order and perceptual instability. The structure is rigorously constructed, yet this stability is constantly disrupted by the eye’s response. The motif of torsion plays a central role here. It introduces a more complex dynamic, guiding the viewer’s gaze in a sinuous movement that suggests expansion, contraction, and depth.

Gouache allows for intense, matte solid colors with great precision. While each band is clearly defined, the overall effect creates an impression of unstable movement, like a continuous undulation. Up close, the colors remain distinct; from a distance, they blend optically, producing secondary hues and luminous vibrations.