For the hair, I simply sculpted over the head in another layer and used a sphere SubTool to sculpt the hair rolled up in the back of her head.
I also used a bit of fibermesh for some of the loose hairs on the back of her neck and head so they could be illuminated by an already-planned back light, but they ended up being too small to even be noticeable.
Sculpting the hair was a simple process
Since the whole dress was extremely complex and I had a close deadline, I decided to change it a lot and ended up making it quite stylized. For the clothing I used the same brushes as before, but also the Dynamic Trim brush for the more stretched and angular parts.
The corset was done by just extracting the equivalent bit of her body, then sculpting some seams in tension folds and bigger folds in the back where her back arches. Again, since I was betting on a low detail approach, I avoided over-detailing this piece to keep the image coherent.
Keeping the corset simple allowed the image to remain coherent
The top of the corset, the more decorated part, was also extracted from the body SubTool. I used a flower pattern as a mask using Spotlight and inflated the unmasked part using the Deformations panel. After that I used the Standard and Pinch brushes to clean it up a bit.
The flower pattern applied to the top of the corset
After looking at the Black Swan
film poster, I noticed that Nina had some small gems in her tiara and across her dress. Using 3ds Max (though this would have been possible in ZBrush by sculpting something similar using the Dynamic Trim brush) I modeled a small gem and made an insert mesh brush with it. I populated the tiara and the top part of the corset with the small gems with said brush.
Adding the gems strengthened the link between my sculpt and the character that inspired it