The motif of light and darkness emphasizes Jane’s social isolation, helplessness, and lack of freedom. Jane observes that light has a profound impact on the wallpaper and the woman she hallucinates within it, as both behave differently depending on time of day:
There is one marked peculiarity about this paper, a thing nobody seem to notice but myself, and that is that it changes as the light changes […] At night in any kind of light, in twilight, candlelight, lamplight, and worst of all moonlight, it becomes bars.
In daylight, Jane’s surroundings are generally “subdued,” meaning that the wallpaper and the mysterious figure inside are still and quiet. In darkness, however, both the wallpaper and the figure become volatile. The trapped woman creeps about and tries to escape the wallpaper, which echoes Jane’s own sleeping pattern: Jane is also relatively still in light because she sleeps “a good deal” during the day and stays up at night, diligently studying the wallpaper in the dark. This rhythm reflects how Jane’s depression—and her husband, John’s, treatment plan of confining her to a room—alienate her from other people, as she’s essentially leading an isolated, nocturnal lifestyle.
Moreover, light and dark are symbolically connected to freedom and agency in the story. Daytime makes it easier for John and Jennie (Jane’s sister-in-law) to control her, because she has some mental clarity and her actions are easily observable. But at night, they sleep while Jane stays up. With her overseers out of the way, Jane can move a bit more freely and do things she cannot during the day, such as writing in her diary. By day, Jane regulates herself and is more agreeable, but by night, she transforms into a restless woman with a limitless imagination. All of Jane’s unrestrained thinking takes place at night—if not physically, she is mentally liberated in the dark. She lets go and allows her mind to wander, to be active and invent increasingly horrific and fantastical things. The dark may remove Jane from reality and hasten her madness, but it also allows her to temporarily escape the social constraints that bind her physically and mentally.
