Get out the flashlight, because Great Expectations mostly takes place in the dark. When Pip first describes the marshes, they're "a long black horizontal line … and the sky was just a row of long angry red lines and dense black lines intermixed. On the edge of the river I could faintly make out the only two black things in all the prospect that seemed to be standing upright" (1.45). The villagers search for the convicts in the darkness; Miss Havisham's house is full of "heavy darkness" (11.55); and basically anytime anything happens, it's dark outside: meeting the convict, traveling to Miss Havisham's, stumbling on Magwitch, and nearly being killed by Orlick. Even Pip's apartment in London looks like it's weeping soot whenever it rains.
This darkness adds to the novel's creepy, Gothic feeling—and it also emphasizes that Pip is, well, a little lost. He's struggling to find his way in a world full of rules that he doesn't quite understand. Obviously, we notice right away whenever there's any light. On the marshes, Joe's forge is like a beacon of warmth and light that bleeds out onto the marshes, and Pip remembers that he used to think of it as a "glowing road to manhood and independence" (14.2).
So, this one's easy: darkness—bad; light—good. Right?
Maybe not. Not all light is good—Estella's candles in Miss Havisham's dark house are watery, and the night Magwitch comes to town, Pip sees little twinkly lights outside of his window: the city's lamps are shaking in the storm, as though foreshadowing trouble. Not to mention Estella herself. Her name means "star," and she's described as "bright" (29.80), but she's not exactly a positive influence in Pip's life.
Something tells us that this novel seeks to shake up those notions and associations that we instantly think of when we see images of darkness and light. Contrasting images of dark and light create a chiaroscuro effect, setting the Gothic mood and emphasizing Pip's struggle to understand the truth.