Symbolism, Imagery, Allegory
There's a lot of talk about race in this book—we dig into it over in the "Themes" section—but here we want to talk about how black and white are used to create imagery throughout Andy's experiences, and especially in his English class. In fact, he even asks his teacher about what the colors mean in literature. Here's his teacher's response:
I'm not sure, Andy, but it certainly is apparent in literature. I don't think it's completely racially motivated, however. The tones of black and white have the greatest amount of contrast between them, therefore writers and poets, who have always dealt with extremes in passion and people, use black and white to create those images of contrast. (19.32)
You know what this makes us think of? The contrast between Andy and his family. They are all black, but Andy is majorly concerned about their investments in whiteness. It's a source of major tension between Andy and his dad, as well as something he's concerned about when it comes to Monty, who's only six-years-old (more on this in the "Characters" section). What matters symbolically, though, isn't the racial elements, but instead the difference this creates between Andy and his family.
The differing relationships to white culture that Andy and his family possess are not directly connected to his suicide. They are, however, part of why Andy doesn't feel understood by his family, particularly his parents. And this is part of why he doesn't turn to them in his hour of need. His ideas of how to be black and how to relate to whiteness are one of many things Andy simply doesn't have in common with his mom and dad.