Tangent

Lighting the model with equal amounts of natural (window) lighting and warm incandescent lighting can produce an interesting phenomenon, pure simultaneous contrast. The optical gray produce by the wrapping of natural light illustrates this clearly (see models neck left side). The line of tangency, if both lights are of the same intensity, should be neutral. However color temperature is influenced by the acuteness of the turn. Of course large fields of color will have complementary effects with the subject also, i.e., blue landscape will help activate model's left.