Awesome shot, what exactly is bounce fill? I'm so unfamiliar with flash so not really sure.
There was no flash used here. It was all natural light, with a negligible amount of interior incandescent.
Maybe I should have said reflected fill cause bounce has come to be associated with flash. Anyway, in the good ole days , bounce fill was just a method of reflecting light -- either ambient as in this case, or flash -- back onto the subject. It's usually done to fill (or increase the apparent illumination levels of) the shadows and reduce the global contrast of that part of the photo.
In this case, the window light was pretty bright and the inside of the room was quite dark. If I had used only window light and exposed for the highlights on her face, the shadows would have gone too dark and they would have lacked detail. That's particularly important here because her face is turned away from the light which puts important details in the shadows.
But taking a large white reflector and using it to reflect some of the window light back onto the dark side of her face from near the camera position, it lightens the shadows and allows the viewer to see more detail in them.
If you study light theory a bit you'll notice an interesting thing. Although fill light usually falls on both the shadow side and the illuminated side of her face pretty equally, it has almost no effect on the brightly exposed side illuminated by the window, while significantly increasing the illumination of the shadows.
It's because we see light logarithmically. It's a really interesting and useful subject if you'd like to follow up on it.
Appreciate your taking time to comment!