Composition and Light Mechanics

the pose is conformed to the flow of the Fibonacci spiral,

the extended left arm and the under-chin is leveled with the horizontal lines of the golden ratio.

her head position sits nicely in the diminishing of the spiral, fitting for the focal region.

The light source positioned behind her is to create contrast around the premise of the head where the darker background uplifts it, this lightplay is like a Ying-Yang.

The under light is slanted and curved to contribute to the flow.