• His extreme quickness has been particularly noticed, and
Joachim von Sandrart wrote in his Teutsche Academie that a woman came from Haarlem and went home the same day, in which short period of time her portrait, cuffs, fur, collar, together with the rest of her dress and both hands, was handsomely completed in a life-sized half-length.
• He produced about 140 paintings in twenty years.