Cynicat Pro continues his explanation of Physically Based Rendering (PBR). If you haven't seen it yet watch part 1, An in-depth look at Physically Based Rendering first.
The Next Video in my Blender Physically Based Shading series where i cover how the Fresnel effect works and what blender is missing from its Fresnel node. hopefully you like it! =3
P.S. for those who don't know Fresnel is the math that describes how reflective a surface is. pretty important stuff.