Hey guys,
I've known for awhile now that shadows are never black and they are usually some shade of purple, but so far I've just been winging it not knowing exactly what I was doing. Sometimes it turns out and sometimes it doesn't. The result is just random because I'm just guessing at the colors and position.

So what I'm asking to all you pros: What is the formula/algorithm/whatever for knowing what color the shadow should be and where/how bright etc. I'm sure there are many factors that would affect this, but I'm just looking for some general rules. I'm ready to take the next step. Enlighten me!

Thanks

The perceived hue of a shadow on a neutral area would be close to the complementary color of the light. In case of yellowish sunlight this would be moving towards a shade of blue (if you ever painted with oil you'd know what amazing depth and realism a dab of ultramarine can give your shades). And I hear classic painters often shifted their shadows towards purple...so you're not really wrong. Besides, dark purple is a very useful color in a limited palette since it can ramp nicely to almost every hue. (The four darkest colors of my Iso-ology palette are all blue and purple-ish)

The darkness/contrast of a shadow "simply" depends on how much ambient light (or additional lightsources and reflections) you have. With one lightsource, no ambient light or reflections the shadow would be pitch black.

For your average scene the shadow would generally be a darker version of the surface it falls on...just remember to put a little blue in there and it will look a lot better :D

Not much realism about that, looks more like there's a secondary blue lightsource. I think it's just a way to get some variance from all the greens and an attempt to separate the trees from the grass a bit.

Well it's a good job you've seen it now! You get banned for not seeing that screenshot on here. Just hope it doesn't still happen!

Edited by theguy - 18 December 2010 at 6:50pm