Is there any way in Blender to adjust the color of shadows cast?
Most of the time you can get a similar/corresponding effect with ambient light or a hemi light.
I am now using hemi lamps…ambiance is just a lamp setting, correct?
Blender’s new render passes are ideal for this. Have a shadow pass and an ambient pass and put the shadow pass through an rgb curve and mix (multiply) the together.
GreyBeard
Nice set up. I wish more people would post simple node setups so I can figure them out better.
Off topic@ greybeard what them is that?
@GreyBeard: Thank you SO much…this is exactly what I am looking to do! However, I have just recently starting using Blender, so if you could explain how to set up such passes, I’d really appreciate it! 
Edit: I am trying to figure this out on my own, but I do not have “Shadow” on my “Render Layer” pass…
see http://mediawiki.blender.org/index.php/Manual/Node_Editor
and http://mediawiki.blender.org/index.php/Manual/Using_Nodes
This is a new feature – you can download a cvs version of blender from www.blenderbuilds.com
GreyBeard
Thanks! I’m using a CVS version from graphicall.org, so I’ll look in the wiki and see if I can get this figured out! (Like I said, I’ve figured out how to set it up, but I’m just not seeing what I should be…)
THANKS so much for showing me this new feature! Got it working, and I just can’t believe how much it has improved the lighting of my composition. (I’m from Denver, so I’m doing a “snowscape”…lighting has not exactly been easy!)
I’ll just warn anyone surfing the forum that wants to try this to make sure they render with the INTERNAL engine. I always have Blender set to render with Yafray, and I found after many freeze-ups that Yafray and noodles don’t get along!
You’ll often find node setups in the Composition, Visual Effects, and Rendering forum. I post them there frequently. They just don’t have anything to do with modeling so you won’t see them posted here very often.
How do I combine the result with the Specular Pass?
With a mix node. This page will tell you how to properly recombine the passes, most of which are “Added” or “Multiplied” back to the result via a mix node. Of course you have many other options and the “Proper” way may not be the best or most pleasing way to do it, depending on your taste, the scene, or the overall effect that you’re shooting for (realistic, surreal, toonish, etc…)
Wow. That’s some feature.
Yes…I LOVE nodes now! If I could just get them to work with animation…
to get them to work with animation, just expand your frame range under the ANIM button.
To get them to process an input image, use the movie clip icon on the Image input node. All is explained in the wiki. njoy!
I’ve been following the wiki as well as trying to solve the problem in this thread: http://blenderartists.org/forum/showthread.php?p=782173, but no luck yet… 
The proper way would be to recombine the passes to the original image. I think I don’t have asked precise enough.
I’ve used “Add” with a factor of 0.8, but I’m not sure whether this will work under any circumstances (light colours and the like).
So the question is, what does the Blender internal Renderer do?
With kind regards
SoylentGreen,
I gave you the link but here it is again. This page tells you how to recombine the passes. I am only assuming that Ton is telling us all how to recombine them in the same way that Blender would do it on it’s own. Recombining passes exactly the way Blender would do it is just a waste of you time and Blender’s newfound prowess. Play with it till you find something that looks good to YOU , not Ton or anyone else.
http://www.blender3d.org/cms/Render_Passes.829.0.html
As far as working under any circumstances…nothing concerning lighting works this way, especially in 3D. That’s one of the reasons that you get so many options to try in Blender. How do you want your scene to look? Cool, warm, dark, vibrant, mystic? I’ve been seeing your name in these forums for long enough that I would have thought you to understand this.
I may seem a bit stubborn, but here we go:
Spec
The specular component, RGB floats. It is masked out by shadow already.
Unlike some of the other passes Ton did not write anything about the way to combine it (or I’m to blind to find it - which may be quite possible).
Well, as you’ve already mentioned I’m using Blender for quite a while, and I’m pretty much aware of the different possibilities and looks of the different shaders. So if I have my look and only want to additionally add some color to the shadows (or use any other nice compositing method), I want to change only one thing.
Yes, and I could use compositing beforehand, but compositing needs more rendering time - sometimes seriously more.
So I use it if I have to, and don’t use it if I don’t want to.
Regards
“Adding” the spec (1.0) to the multiplied diffuse and shadow pass will make it look like the render would look without using passes.
GreyBeard