What is causing the lighter outine? Looks a bit like some Sabbatier effect but not quite. Can't see it in the thumbnail but in the full size image, it makes the portrait "pop" a little bit.
I have burned the background. I have trimmed the figure of the girl in a somewhat greater mask. Later I have exposed the backgroud 10 second pluses. It is an old technique that already used J.L Sieff.
I find this portrait very pleasing to look at indeed.
I think it is because of the extra work you have put in, it almost has a 3 D effect, making the model stand out from the paper. It has a lovely light to it and it brings out her eyes and lips beautifully.
I'm not much of for portraits and such, but this is striking! I love the placement, and that cool light effect. I am also perfectly happy that her sweater holds no detail. It is VERY nice work!
I think the effect you have created is very striking helped by the fact the model is beautiful.
I am a fan of J.L. Sieff but know very little of his technical workings.
Maybe you could even accentuate the halo effect around the head , but it seems you are quite happy with the print and you should be. I also like the flat black of the sweater, the middle grey tones of the background and highlights of her face, but I am really drawn to her eyes which her haircut helps bring out even more.
The outline looks like you attempted to burn the background and failed to blend it with the model. I know it is intentional on your part, but to me it looks forced and unnatural. Personally, I would prefer to see the background backlit more naturally, or use an even tone throughout.
The quality of light on the model , on the other hand is superb. Very nice lighting on the face. The black block of her body is placed very nicely, and provides a bit of abstract balance to the image. A very nice portait overall.