It's a bit of a tossup with me and photorealistic art—some just remind me of the photograph, and the portrait doesn't add anything for me. But there are some artists that apply this technique to the fantastic, so there isn't a photograph, or somehow manage to be both moody and photorealistic at the same time.
This motherfucker, though—damn, I feel schooled. That's a really full range of greys and it's all so smooth...I don't feel like a black and white photo would look just the same, somehow. This feels particular.
Here's a sped-up video of the shading of the Emmy Rossum portrait: