The first set of images were taken on a sunny day with light pouring in through a window. I placed a large reflector opposite the window so that it would act as a fill light, I also used the golden side of the reflector to add more warmth. In some of the post processing I thought that this was too golden and reduced it slightly using the temperature slider even though I had the camera set to the correct white balance for these conditions.
The first image I have kept although I am not sure about it. The problem is that the eyes are not lit, it would have been a better image is the majority of the face was in direct light rather than shade, it leaves the viewer guessing where the main eye is.
The next image taken from the same sitting has a lit the face up more, this I achieved by moving the reflector around a little and slightly closer. Here I was playing with props and thought a cup of coffee may work. I am not sure about the cup, it may be too much, but really like the light on the face in this one, and as this is what this exercise is all about I have kept it in.
For the final image from this sitting I closed the blinds to the window so that they cast a shadow of horizontal lines over the sitting. The warmth of the reflector didn't work for this one as well so I reduced the warmth post processing giving it a cooler effect. I like this one as it looks more serious. The left hand side of the face is well lit in this one leading into the left eye with the slatted light creating interesting shadows on the right hand side of the face creating a form of mystery.
And finally I took a shot using 100% natural light on a sunny room that had nothing but white walls, so that the light was brilliantly diffused. The strongest part of the light was behind the sitter which has helped to light the outside of the hair. If I was producing this as a final image I would have to remove that annoying strands of hair......as shown in the second version....this was done easily with the spot brush tool in Photoshop.