Houbraken relates several instances of his remarkable facility of hand.
He frequently painted a large landscape and inserted all the figures in
a single day--feats so much admired in Salvator Rosa, and Gaspar
Ponssin. On one occasion he commenced and finished three portraits, on
canvass, of three-quarters size, with heads as large as life, from
sun-rise to sun-set, on a summer's day. Lanzi warns all artists,
especially the youthful aspirant, not to imitate such expedition, as
they value their reputation.