In his Windows series, a group of twenty-two paintings made between April and December of 1912, Delaunay rejected painting's traditional function as a window onto an imaginary world. Instead he turned to the pictorial surface as a place where the process of seeing itself could be recorded. "Without visual perception there is no light, no movement," Delaunay wrote in the summer of 1912. "This movement is provided by relationships of uneven measures, by color contrasts, which constitute Reality." Light and its structuring of vision, the simultaneous contrasts of colors and their steady rhythmic motion, became the subjects of Delaunay’s Windows, setting the stage for his move into abstraction. "The Windows," he wrote, "truly began my life as an artist."
from Inventing Abstraction, 1910–1925, December 23, 2012–April 15, 2013