Lighting with mirror surfaces can be tricky. It seems like you have to sacrifice that crystal clarity in order to shed some light on your models…but that isn’t always so.
Take this example:
There’s nothing in this scene but some models, a mirror plane, a camera, and a background. Obviously this isn’t going to work. The first obvious solution is to lighten the ambient light color. Here’s what happens:
The models are more visible but now the reflection is all washed out. I don’t like this so the ambient light is going back to black. Next, I’ll try adding a light (Omni, as its shadows are turned off by default).
My background looks sharper and I like the effect the light has on the models, but my mirror plane is still getting washed out way too much. Fortunately, there is a simple fix here.
Select the light and go to the object modify panel. Under “General Parameters” in the Shadows section, click the “Exclude” box. From the left list, select your plane and move it over to the right list using the double right arrows. Make sure “Exclude” and “Both” are selected, then click OK.
Now I get the look I want; crystal clear reflection, well-lit models, and sharp background.
These settings can be manipulated in several ways and can be applied to any object or model in your scene.