Just rewatched this recently and I realized something that I don't remember anyone talking about when it first came out.
The character Redd played by Morgan Freeman is a color blind casting. In the time period in which that story is set a Black prisoner would never have survived among an almost 100% white prison population. There were only maybe two or three other Black faces seen among the prison population, one of them played by Freeman's son Alfonso. No reference was made to Redd's color. Nothing seemed strange or off about it. Freeman just so naturally embodied everything about what that character should be that no one noticed a Black man among all white faces spanning years 1947 to 1967.
That is remarkable and if there was mention of it at the time it came out I missed it. That is what colorblind casting should be.