Study of a Sibyl (3)
Red chalk over Stylus, 262 x 167 mm
British Museum, London
Study for the Three Graces (3)
Red chalk over stylus, 203 x 258 mm
Royal Collection, Windsor
Modello for the Entombment (3)
Pen and ink over stylus and black chalk, 289 x 298 mm
Galleria degli Uffizi, Florence
I chose Raphael for his classical grace in his sketching and for his attention to detail and composition. His architectural tendencies are evident in the structured nature of his drawings as well as his use of chiaroscuro, or strong contrasts between light and dark.
(1) Wikipedia: Raphael
(2) Quoted Pon:114, from lecture on The Organization of Raphael's Workshop, pub. Chicago, 1983
(3) Web Gallery of Art. Drawings by Raffaello.