To make this drawing, Warhol started by tracing the soup-can logo from a mailing envelope sent by the Campbell's Soup Company onto a sheet of paper. He likely enlarged that tracing in a projection, which he then traced again on this sheet. The thirty-two paintings that make up Campbells' Soup Cans are also based on the same soup-can logo. Warhol may have used pencil drawings like this one to increase the size of the projected image in stages, which helped to preserve the graphic clarity of the logo when it reached the larger scale of the canvases.
from Andy Warhol: Campbell's Soup Cans and Other Works, 1953–1967, April 25–October 18, 2015