A simple experiment in lighting.

To keep things simple, a basic lambert shader was applied to the model. There are 4 spotlights: two on the sides, slightly forward and angles down at the face, one at the front with less of an angle, and one at the back further away and angle up steeply.

3 versions of the lighting were then rendered, The default (All 4 lights with 1.0 intensity white light and black shadow), varied intensity (different intensity levels white light and black shadows), and colored (same varied intensities with different multiple colors for the lights and non-black colors for the shadows).

I think the colored lighting makes a subtle yet very important difference, but I already thought that. What's more important is that using colored shadows is even better. I plan to incorporate more colored shadow for lighting in future images.

The most important take away is: DEFAULT, UNIFORM LIGHTING SUCKS! Seriously, even just changing up the intensity levels a bit really makes a titanic difference. Obviously, less light means the contrast between lit areas and shadow areas is going to decrease. Colored shadows, however, can be chosen to work with the color of the surface in order to make the shadows complement their surroundings. Look at the difference on the lighter shadows present between the eyes in the 3 images. On the side view, you can see on the cheeks how the colored shadows blend in a bit of a purplish hue, rather than just be a darker shade of blue.