Window light portrait

I took this portrait of a Kazakh woman in ceremonial dress using only window light. This is in Shymkent, Kazakhstan. The interior of the room didn't go as black as I had envisioned, so in Photoshop I selected her using the quick selection tool, feathered the edge by one pixel (Select > modify > feather), and then used Select > inverse. This grabbed only the background. I then used Edit > fill, and in the dialog box I chose 'foreground color'. Black was in the foreground color box at the bottom of the tools palette, thus black replaced the original background. To make this perfect, I used Filter > noise > add noise, and chose 3.5. This is necessary because when you fill an area with a color, it's a solid color with no noise at all. Since our digital images all have at least some noise, to make the image look entirely photographic (as opposed to digitally manipulated) I had to add the same noise level as the rest of the picture. My settings for this were 1/125, f/5.6, 800 ISO, and I used a 100-400mm Canon zoom.