Wednesday, December 30, 2009

18 The color of shadows


THE color of light and the color of shadow relate to each other. If this relationship is off the reality of the scene is marred. Getting shadow color right is often hampered by the complex light effects that modulate its color.

The academics solved the problem of shadow color by keeping all the shadows uniformly warm. They often painted a very warm underpainting that was preserved in the final painting. This underpinning was often burnt sienna or similar hue. If there was any modulation of the shadow color it was by very subtle glazing. This gave a similitude of reality by ensuring that the values were extremely accurate. However, color vibrancy was lost following this formula.

The revolutionary idea of the impressionists was that reality was much more complicated and could not be described using the brown formulas of the academics. Many painters began to paint in the field using direct observation to guide their color choices. Some effects were so obvious that immediately impressionist paintings began to reflect a more vibrant and colorful reality. These newly discovered methods also allowed the impressionists to pack more observation into their paintings. Instead of brown shadows we began to see the purple and blue shadows of the Impressionists. But there were even more subtleties to be discovered.

I was looking out from a twenty-four story building onto a building below. There had been a recent snow and one of the air-conditioning units on the roof was casting a long shadow. I could clearly see how the shadow was warmer closer to the air-conditioning unit and gradually cooled as the shadow lengthened. For me it adequately explained and demonstrated Monet's envelope. This principle says that objects that protrude into the blue amorphous envelope of the sky become cooler in color. Objects or spaces that retreat from this envelope become warmer. For example, spaces and deep recesses within trees and rocks will often appear warmer than the less recessed spaces right next to them.

It's not an easy principle to grasp. I think of it as the sky being a kind of bluish gas that wraps itself gently around every object. There are probably problems with this model and as we understand with greater clarity the natural phenomenon around us we will paint paintings with even greater vibrancy and vision. Let me know if you have any insights into this fascinating phenomenon.

Brad Teare © 2009


  1. Good post, Brad. I always like to tell my students that what's happening is the light from the sky is spilling down into the shadow area and affecting the local color. The reason the shadow is less blue (or less cool) as it approaches the object casting it is that the object itself is blocking some of that light from spilling in. Also, the shadow gets darker as it gets closer to the object for the same reason.

  2. Michael,

    I like your word "spill". That gives the phenomenon a fluid metaphor as if coolness is flowing around objects. Very evocative.

    I appreciate your perspective. Let me know if you have additional insights regarding the video.

  3. Great information.
    James Gurney wrote a post once noting something similar, he had a great example of a rock cliff in shadow where the upward facing planes were cooler than downward facing planes on the cliff.

  4. Thanks Craig. Gurney Journey is a great resource. I will definitely check out that entry.


Thanks for your comments!


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