I have finally freed myself from the sticky medium of paint, and am working directly with light itself, Man Ray wrote in 1922, announcing his discovery of rayographs.
Man Ray made rayographs by placing objects directly on, or close to, light-sensitive paper, which was then briefly exposed to light. He was not the first to use this process, but he mastered its effects and was proud enough of the technique to brand it after his own name.
The procedure allowed Man Ray to produce images simply by controlling the direction and intensity of light. It also challenged the traditional value attached to the touch of the artist in a way that paralleled Duchamps readymades.