Riley spent two years copying Seurat’s painting, Bridge of Courbevoie, to learn about his painting technique and his use of complementary colors. She describes the process as “being a revelation to her” with regard to color. Soon after, in 1966, Riley begins to use color to achieve new optical effects. By juxtaposing lines of complementary pure colors she can affect the perceived brightness of the individual colors.
Riley works meticulously, carefully mixing her colors to achieve the exact hue and intensity she desires. She explores color interaction first in small gouache color studies, then moving to full-size paper-ad-gouache designs (as in the photo at right). The large-scale canvases are then marked up and painted entirely by hand — first in acrylics, then in oil.