We feel similar distinctions in the case of all great draughtsmen.

Titian's chalk-studies, Fra Bartolommeo's, so singularly akin to Andrea del Sarto's, Giorgione's pen-and-ink sketch for a Lucretia, are seen at once by their richness and blurred outlines to be the work of colourists.

Signorelli's transcripts from the nude, remarkably similar to those of Michelangelo, reveal a sculptor rather than a painter.
Botticelli, with all his Florentine precision, shows that, like Lionardo, he was a seeker and a visionary in his anxious feeling after curve and attitude.

Mantegna seems to be graving steel or cutting into marble.

It is easy to apply this analysis in succession to any draughtsman who has style.