Old master in close-up

I've always been amazed by the old masters of illlustration, Norman Rockwell, J.C. Leyendecker, those kind of guys. Great craftsmen, painting vituosos whoes works are widespread and well known. They worked rather big, in order to create spectacular detailed smaller reproductions. By doing so it is almost impossible to study the works, how they are built up, but I've found a blogpost of a guy who went to see some originals and published some close-ups so that we can actualy see the brushstrokes. And they are FAT! Beautifull stuff.