That's a question I get asked all the time. The answer is "no" and it's "yes." The first thing I learned about painting a face is that I have to stop seeing a face, a mouth, an eye, an ear, a nose. It's just shapes and colors, darks and lights. If I think of an eye as an eye, I make it too round or to almond shaped and exactly like the other one; if I think a mouth is a mouth, I make it too red, too crescent shaped.
My portrait paintings are just like every other painting... they go through an ugly stage. I'm never comfortable letting someone see a portrait that's not finished. I can see in their face... "ummm... yeah..." while they wonder what to say. In the first stage of my portraits, they look very creepy, kind of like the zombies from Thriller, while I'm getting the darkest darks blocked in. The second stage happens pretty quickly, and I have a lovely portrait of some little child - just not really the one I'm supposed to have. The most tedious part is what follows. What tiny brush stroke will it take to make these lips, his lips? What's wrong with the shapes of that eye? Where is that nostril supposed to be?
Finally, there's the, "Oh, there you are!" moment followed by a big "Whew!" because the stress level is usually high by then.
So, my answer is no, it is not hard to paint a face. But, if you want a specific face... well, yeah, it's hard!
Isn't he a sweetie and a cutie!! (Both 50 years ago and now!)