G'day Ngaire,
http://www.youtube.com/watch?v=qrKiutheOzg
Out of doors photo taking, for purposes of painting reference, is a mighty challenge. I asked that we start our session about 4 o'clock in the evening when the sun would be low in the sky, but still you're up against those light / shadow issues.
I think the worst in this regard is the first one posted. It lacks any significant shadow on her face. The others in the park setting were only slightly better. I was pleased with the ones on the bridge (this is a pedestrian bridge that spans the Arkansas river which runs through Tulsa). There are some good dramatic shadows there. This may be partly due to the fact that the sun was very low in the sky by the time we had changed locations. And being somewhat enclosed I was better able to manage the light.
I'd like to have another go at this gal indoors with a soft window light.
Getting these issues right is an important point when you are trying to model these features with paint and not have them look flat.
In this shot I can see that if I had paid more attention to the light on her face I could have moved her head slightly to her right. This would have allowed the light to catch her left cheek and given a much more interesting light / shadow pattern. Also, the scarf is a bit much, I think. There is only so much I can control when it comes to a woman's wardrobe.
Thanks for your interest, Ngaire.