The vivid language of maps becomes more interesting when we consider that the word darkness still retains its traditional meaning of evil and dread. The fact that Marlow applies the concept of darkness to conquered territories once again indicates his negative view of colonialism. He clearly states that colonists are only exploiting the weakness of others. Their spreading over the world is no more noble than other types of violence and thievery. On the map, places that are blank and devoid of outside interference are apparently the most desirable.
Darkness has another application a color of skin.
Much of this chapter is spent discussing Marlow's primary encounters with and observations of the natives of the African Congo. The darkness of their skin is always mentioned. There is absolutely no differentiation between dark animals and dark people. Even the rags worn by the native people are described as tails. The constant dehumanization of black people is almost obsessive on the author's part.