The most famous and iconic way to represent evil are monsters and darkness. In the play the three witches embody this sort of representation through their spells and what seem to be magical powers. We can differentiate between what characters seem good and evil in the play by the use of light imagery and how they speak. And the witches are clearly set apart from the rest of the characters from this standpoint.
Another of Camberwell College of Art graduate Sean McSorley's illustrations for the Folio Society's illustrated edition of Joseph Conrad novella A Heart of Darkness. Images were created using monoprinting and feature rusty reds and murky greens and browns