The index and the diagram are, on the face of it, incompatible types of sign. While the index has a close, causal or tactile, connection with the object it signifies, the diagram is a sign that involves statistical abstraction, such as trends in the stock market or the weather. This chapter focuses on a hybrid form of representation that has aspects of both. The graphic trace is an indexical diagram. It takes from the index a registration of something unique, the impress of an individual thing, while incorporating the diagram’s abstraction from what is immediately given in perception. The use of the graphic trace in art is explored by drawing on an essay by the German poet Rainer Maria Rilke, the chronophotography of Étienne-Jules Marey and the work of artists including Marcel Duchamp, Susan Morris, Brian O’Doherty, Gabriel Orozco, Amalia Pica, and Nedko Solakov.