Humorous Portraits Smiling faces often look unnatural in a painting, because it is difficult to hold a cheesy smirk long enough for a painter to map out the front teeth. It can be done to some extent by smiling just for the five or ten minutes while the mouth is painted. And some people are incessantly grinning and to paint them without even the hint of a smile seems a violation. Of course you can use a camera or lens to help. I don't know how Franz Hals managed his Laughing Cavalier. David Hockney's book Secret Knowledge may give us a clue.