Our own Morgan Meis in The Smart Set:
Frans Hals is often described as a “loose” painter. You can see what that means in one of Hals' great paintings currently on display at the Metropolitan Museum of Art. The painting is called “The Smoker,” from 1625. You wouldn't be surprised, though, if someone told you it was painted 250 years later than that. The face of the young man smoking a pipe at the center of the painting is rendered in almost impressionistic strokes. A dab of red here, a curve of yellow there. The collar of the man's shirt is created with a rough stab of white down the middle of the canvas. The painstaking brushwork of other Dutch masters from the Golden Age is notably absent. That is not to say Hals was sloppy, a crime for which he has sometimes been accused. Hals labored at his chosen craft all life long. It is just that he worked very hard to achieve a looser style. You can see it even in his formal portraits, in works such as “Portrait of a Man” from 1636-8. The face of the man in that painting is rendered with all the precision you might find in a Rubens of roughly the same era. And the expressiveness of the man's face is reminiscent of Rembrandt. But if you look at the man's left arm, the one cocked at his hip, you notice that the style devolves (or evolves?) into that of the loose Hals again. The elbow — and the folds of garment around the elbow — are painted with the same rough gestures and impressionistic swaths of color that are so startling in “The Smoker.”
More here.