Gianfrancesco Penni
Born in Florence to a family of weavers, Penni entered Raphael's workshop very early in his life, and collaborated with him on several works, including the famous Rooms of the Vatican Palace, as well as the frescoes of Villa Farnesina, both in Rome. Heinrich Wölfflin and some other writers credited him with the entire execution of the Raphael Cartoons, with Raphael only creating the initial design, though more recent writers believe Raphael did much of the work himself.
Raphael
In later works painted by the workshop, the drawings are often painfully more attractive than the paintings. Most Raphael drawings are rather precise—even initial sketches with naked outline figures are carefully drawn, and later working drawings often have a high degree of finish, with shading and sometimes highlights in white. They lack the freedom and energy of some of Leonardo's and Michelangelo's sketches, but are nearly always aesthetically very satisfying. He was one of the last artists to use metalpoint (literally a sharp pointed piece of silver or another metal) extensively, although he also made superb use of the freer medium of red or black chalk. In his final years he was one of the first artists to use female models for preparatory drawings—male pupils ("garzoni") were normally used for studies of both sexes.