[Chris Saper]

To summarize briefly how I approach shadows:

First, regardless of the color of shadow, areas in shadow abhorr strong saturation of color, sharp edges, and high contrast in value, in comparison to areas in light.

With respect to color, I use desaturated local color and incorporate into the shadow the complement to the color of light, and also consider adjacent and/ or reflected color.

So for example, when a light source is warm, the local color in shadow is desaturated (grayed-down); is influenced by the complement to a warm light (for example, blue); and is influenced by adjacent reflected color. Every different situation will present a unique answer to the qestion: How much?"

When a light source is cool, the opposite thing happens. The local color in shadow is still desaturated, and is warmed in the shadow by the opposite color to the color of light (in this case, a bluish light would result in warmer color in shadow). Again, there would be some influence of reflected color.

In situations such as Celeste describes, nostrils are indeed warm - living skin color bouncing against living skin color is always warm. Fingers that touch each other are another good example of this, as is the line where lips touch each other.

Some years ago, I took a workshop from painter Daniel Howe, who had a somewhat similar approach to what you read, Leslie, except rather than specifying "blue", he described adding the complement to the color of light.