Light and dark imagery pervade this story. At the beginning, we learn that the narrator's street has "dark muddy lanes" and "dark dripping gardens." His own street is "blind," as if it were also in the dark, even though “blind” also means that the street is a dead-end. These elements of darkness suggest the narrator's lack of awareness, as well as the blindness that exists in his own community.
Light is associated with Mangan's sister, the narrator's love interest, whom he knows mostly through observing her from his house and whose beauty intrigues him. He sees her figure by way of "the light from the half-opened door." The bazaar is also associated with light when the narrator is looking forward to it. Later, though, because he arrives at the bazaar late, he finds the hall with closed stalls and "in darkness."
Joyce uses light and dark to develop the theme of harboring false hopes and having them exposed. The narrator builds the expectation that Mangan’s sister and the trip to the bazaar will lift him from his drab existence. When he arrives at the bazaar, his dreams are shattered by the shabbiness of the place. The darkening hall symbolizes the narrator’s realization that his dream was an illusion.