This chapter shows that the notion of skin colour emerged only gradually since the sixteenth century and became a prominent marker of race in conjunction with the development of racial anthropology during the Enlightenment. The colour of a person used to be perceived as body colour and often referred to as complexion, a term linked to the ancient medical theory of the four humours and temperaments. The artistic making and mixing of flesh tones was closely linked to humoral theory. By the eighteenth century most anatomist interested in the microscopic structure of skin agreed that the body's colouring matter – later called pigment – resides in an outer layer of the skin. This was demonstrated in an early medical illustration by Jan Admiral made for a Bernard Albinus' anatomical treatise on the colour of the skin. Interestingly, the print also uses a new technique of colour printing, and the argument is that skin colour is simultaneously an artistic, technical and medical problem in this colour mezzotint. Finally, an analysis of Girodet's Portrait of Belley and Benoist's Portrait d'une negresse suggests that skin colour is both a political and representational problem in these portraits painted shortly after the French Revolution.