Monday, December 6, 2010

Ambient Light




The holiday craziness is starting to heat up! I am trying to stay ahead and sane this year. Although my resistance is probably futile, I have to try!

Here are two very similar paintings. One of these was done as a class demo on brushwork and edges, and the other one is a variation I did at home. It doesn't matter which is which - I just wanted to share with you something I touched on during the demo.

Ambient light. When painting a scene like this where the sun is not out, the sky becomes the primary light source.  And because the light source is the entire sky, as opposed to the intense directional light that the sun provides,  the effect is much softer and often much cooler.  Although not necessarily a rule carved in stone, the value jump between light and shadow of a common surface tends to be much closer, and the cast shadows are not clearly defined.



And here's a color strategy for mixing the light side of the foliage (or barn, grass, whatever) : I first established the dark side of the tree - a very low chroma green, then I painted the sky.  As you can see from the two paintings, the main difference is the sky color - it's whatever dusky color you want.

Then I mixed the sky color into the shadow-side-of-the-foliage color to get the light side of the foliage.  Since the sky is the light source, and it has color, it affects whatever it's illuminating. You can see that the bottom painting has a cooler foliage color as a result.

Here's the disclaimer. Don't take this as a formula! It's a good starting point, but depending on the color you start with (the dark side of the tree) and your choice of the sky color, you may end up with a color that is much grayer than you want, so always expect to make adjustments.


And another thing. This doesn't really work in direct sunlight situations, because the sky is a secondary light source, and the color of the sunlight trumps it. However, you might try it to illuminate the shadows that face the sky~  (Ever seen blue shadows? Uh huh.)

9 comments:

  1. It's summer here in Oz now and it's been cloudy and raining for seven days straight (following some spectacularly bright and hot spring days!).

    I admire anyone who can capture the magic of a cloudy day. I go out occasionally with all intentions of painting without bright sunlight but I struggle to see beyond the grey and usually return home with blank canvas.

    Maybe I'll make it my new year's resolution to "just do it" :)

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  2. Great post Terry! I'm going to give this a try.
    This is the season for giving, and you just gave me a great idea! Thanks!

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  3. so helpful! Thank you Terry.

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  4. Enlightening idea- thanks! But on those sunny days, when the sun hits directly, say on a rock surface, the light would be yellowish, yes? What about on a less direct plane of that same rock- if it's not in shadow, would that plane reflect a more bluish light? Sorry to get complicated, but that's a specific problem I've come across.

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  5. Thanks Everyone! I just read what I wrote. It's not very concise, is it. LOL thanks for taking the time to decode it!

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  6. hi Terry, there is some thing no too clear in what you say. you say that you mix the sky color into the shadow-side-of-the foliage color to get the light side of the foliage. that is if you did the hole tree in the shadow first and then you apply the color of the sky on the parts that are suppose to be the light parts of the foliage, is this what you mean?

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  7. Jesus, not exactly. I do the whole tree in shadow color first, to establish the silhouette, but then I mix the light green on the palette by mixing the sky and the shadow green. I usually don't mix on the canvas, just on the palette.

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  8. Now I got it,what you say is what I mean,Thanks for getting it clear.This is a good tip.Cheers

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