Very few subjects are totally backlit with no light at all falling from the front. A person with his back to a bright window will have light reflected from an opposite wall falling on him. Someone standing outside with her back to bright sunlight will have light falling on her from the open sky in front of her. In either case, you’ll need to increase exposure to record the light falling on the subject—and this light will deemphasize facial texture and dimensionality.
Tip: For spark in a backlit portrait or silhouette, try compositions that include the light source. This can drive your meter crazy, so bracket your exposures.
Learn how to achieve this style of lighting at our studio workshops with Jay Terry. All the details here... http://northof49photography.com/lighting-and-editing-workshop