I especially like the girl on the right -- her look is so open and approachable. Her open mouth and large, child-like teeth are a great element. To me the girl on left has an expression that's a little staged or less-than-natural. I can't quite pin it down but it just doesn't seem a "normal" pose in a photographic setting, which makes me think it's affected. Maybe she just blinked?
I like the print on warm paper. Hadn't noticed that before, but I see it enhances the work here.
Can't say enough about the right-side girl's candid expression. It's great.
John, I can understand where your comments are coming from. The expression from Briana is very real. She's very comfortable with me photographing her, as this is I believe our fifth session. Most importantly, she's very quiet and shy by nature, and closing her eyes is a natural comfort measure. It's not a blink. It's actually more of a challenge to get this girl to look at the camera without altering her natural expression.
Sometimes what doesn't seem normal in a photographic setting is that which comes naturally to the subject. It's also worth noting that the setting was an easy chair in their parents' bedroom near a big set of french doors. It's a lot more difficult to get these expressions in a sterile studio environment.
Incidentally, you might be surprised to know that these girls are only nine and ten years old. Intensity comes in all sizes.