How do I only apply reflection to certain area?

I have a UV mapped object and a stencil map. I want it to reflect based on the texture map, white being full and black being no reflection.

How should I do this?

Apply the black and white image to the Ray influence under Shading in the texture influence options.

Here is another way if you want two distinct materials being mixed by a B/W map.
You use the materials nodes.


25_mix_materials.blend (632 KB)

Ah, thanks.