Donatello.
CIX
Drawing is the probity of art.
Ingres.
CX
To draw does not mean only to reproduce an outline, drawing does not consist only of line; drawing is more than this, it is expression, it is the inner form, the structure, the modelling. After that what is left? Drawing includes seven-eighths of what constitutes painting. If I had to put a sign above my door I would write on it "School of Drawing," and I am sure that I should turn out painters.
Ingres.