Throughout Heart of Darkness, light and dark play numerous roles in relationship to physical as well as conceptual aspects of Marlow’s understanding of the European imperialist domination of Africa. The symbolic representation of the contrasting terms relates to physical attributes of people, things, and the environments in which both are found.
Race is the most obvious outward manifestation of light and dark in terms of skin color. The attitudes of the Europeans are associated with their ideas about light, or enlightening, the African people, whose ignorance of Christianity is viewed as a kind of spiritual darkness. Europeans often referred to Africa as the “dark continent.” Marlow comments ironically on these ideas, associating darkness with blindness, which is appropriate to those who “tackle a darkness.”
Joseph Conrad deliberately makes light a central element of imperialist exploitation through the symbol of ivory, which is the highly coveted object of the trade in which Kurtz is involved. The pale color of the substance is part of its appeal. While Kurtz’s excesses represent an abuse of normal commercial relations, Marlow’s narrative also shows the dark side of trade, which depends on the abuse of indigenous African laborers to create the necessary infrastructure. Light is not always positive, as it can be associated with death, such as through the bones displayed in Kurtz’s camp and Kurtz’s extreme pallor near the end of his life. Darkness is also associated with hidden things, decay, and degradation.