What is known about Picasso's early technique was gleaned from contemporary accounts and complemented by a technical examination of actual works. According to Fernande Olivier, Picasso's mistress at the time, his canvases were prepared in a rented building in Montmartre where they could dry until ready for use. Picasso favored a "fine tight canvas with a very smooth grain, less absorbent than others (Olivier, Picasso and His Friends, p. 129)." Picasso prepared the canvases after stretching them onto a wooden stretcher, sizing them with animal (rabbit skin) glue, and coating them with a preparation made from lead, chalk, and glue called gesso, which provides a smooth, white surface to receive the underdrawing and painting. The prepared canvases would then be transferred to the Bateau-Lavoir studio, which by all accounts was a rather cramped and cluttered space consisting of two dark rooms which also functioned as a bedroom, kitchen, and kennel. At nearly eight feet square, Les Demoiselles d'Avignon must have occupied almost an entire wall of the Bateau-Lavoir during the early spring of 1907, when Picasso started work on the canvas.