Douw designed everything from nature, and with such exactness that each object appears as perfect as nature herself. He was incontestibly the most wonderful in his finishing of all the Flemish masters, although the number of artists of that school who have excelled in this particular style are quite large. The pictures he first painted were portraits, and he wrought by the aid of a concave mirror, and sometimes by looking at the object through a frame of many squares of small silk thread. He spent so much time in these works that, notwithstanding they were extremely admired, his sitters became disgusted, and he was obliged to abandon portrait painting entirely, and devote his attention to fancy subjects, in the execution of which he could devote as much time as he pleased. This will not appear surprising, when Sandrart informs us that, on one occasion, in company with Peter de Laer, he visited Douw, and found him at work on a picture, which they could not forbear admiring for its extraordinary neatness, and on taking particular notice of a broom, and expressing their surprise that he could devote so much time in finishing so minute an object, Douw informed them that he should work on it three days more before he should think it complete. The same author also says that in a family picture of Mrs. Spiering, that lady sat five days for the finishing of one of her hands, supporting it on the arm of a chair.