I think the sketch of the woman represents the Europeans bringing civilization to Africa. The candle represents what the Europeans are bringing to Africa and what they would see as light being brought into darkness. The woman in the piece is blindfolded to represent that the Europeans don't fully understand what they are getting into and they cannot 'see' the perspective of the native people. The woman's face appearing sinister above the light of the torch shows the corruption and evil that lies within many of the colonists, such as Kurtz.