I'm a huge portraiture fan and this is a beautiful piece. Just fantastic!
The shading work is beautifully handled. I found the shadowing especially well done in her face - you were able to capture the face and how it rounds off considering how bright your light sources are (around her eyes, the left cheek, the shadows under her nose and lower lip). The second part that I enjoyed was the dress top - it's ridiculously hard to show light on black fabric and you handled it amazingly well - and her bracelets. The black bracelet looks round and not blocky. The way you changed the angle of the light sources hitting each black square on the bracelet was great. Also, I know these are weird parts of the anatomy to point out but I LOVE the time you put in to show the skin crease next to her right arm pit and along her neck. They're subtle but, because of how strong the light sources are, give the viewer a feeling that this is skin.
There are two areas that I look at and question. The first one is the shadow under her necklace. Not so much the darker shadow between her breasts but the shadow as it moves up her chest towards her left shoulder. It seems a bit too large, like the necklace is facing the viewer straight on when it should be a bit smaller. The other part that throws me is that line of hair on her right side that starts just to the right of her right eye and moves down. It just seems like it makes that section of her hair look like an ocean wave to me.
Overall, beautiful piece. I think the detail work and shading was handled incredibly well. Thank you for sharing it.
(By the way, I don't know if it's just my computer but the zoom-in option isn't working.)
Damn! Love the detail in the hair, the lips, the bracelets, the shading of the shirt, and especially the creasing on the breasts where the shirt tugs. The one on the right is a little odd, but the one on the left is on the cusp of perfection. Well done!