compare the noble "torch bearing, sword wielding " civil men going into the heart of darkness with the portrait of the woman blindfolded

THe painting itself answers your question. The painting at the Central Station is perhaps the most extensive symbol in the novel. The painting is of a blindfolded woman carrying a lighted torch, which distorts her face. The woman likely symbolizes the Europeans who have come to civilize the natives. The torch she carries represents the European customs and values that they try to force upon the native Africans. The woman is blindfolded because the Europeans cannot "see" the negative effects that their customs have on the natives. Her face has become distorted because, to the natives, the European customs seem rather repulsive.