I'm trying to create a cycles lamp shader that only lights up the diffuse component of the materials around it. Kinda like having its Glossy component turned off in the Ray Visibility box under the object tab. But it is not working. I seem to be missing something quite basic.
Here's my node setup:
When the material is reflecting sharply (with roughness turned down to zero), the node setup works. But with blurry reflections, it stops working. What is it that I'm doing wrong?