As I have mentioned elsewhere, I had the good fortune to spend some time with Gil Kane back in the early 80s. Kane is/was an undisputed comics grand master of the Silver Age. He had a style that was instantly recognizable, full of energy and confidence. And for good reason. He worked very hard at his craft.
When I met with him, I was old enough and experienced enough in illustration to have a pretty good portfolio which, when I showed it to him, he seemed to like enough that we 'talked shop', while I bought him lunch. It was a dreary rainy day, but it was dazzling for me, as Kane was showing me drawings of his that he was willing to sell. I bought a number of them, but I was intrigued by a sheaf of drawings in his case that he wasn't showing me. When I asked about them, he said, 'oh you wouldn't be interested in those, they're just my finger exercises.'
Even more intrigued, I asked to see them, and they were sheet after sheet of anatomical drawings, done as practice to 'stay in shape', as he put it. Drawn from the imagination, they were human figures drawn from all angles, using a classic constructive method, visualizing joints and such.
When I told him how much I admired them, he seemed pleased and started to hand me one to keep. But then he kept it back and set it in front of him on the table. We were done eating by then, and there was no one around as we quietly chatted about art and comics. Well, darn it if he didn't turn that page over and start doing more finger exercises right then and there as we were talking. He had a selection of pencils, pens and markers with him and for these he used a red ballpoint pen directly on the comic book page bristol board.
The page, and details, that you see below with the faces were the exercises he did while talking with me. He explained somewhat as he drew, so it was a grand art lesson from a master! When he was done he started to hand it to me, saying 'here, this is for you'. I had to ask him to sign it, so then he pulled out one of the markers he used for more finished drawings to do that.
I was able to commission him to do several character drawings over a period of time, one of which I've already posted (Dejah Thoris and John Carter). I will post the others somewhere down the line.