Last week, Torii-san measured the backscattering properties of DLC and soot of a candle distributed on an Aluminum surface.

I have now calculated the respective BRDF. The DLC backscatter is now symmetric and shows a sharp and strong peak (>100 1/sr) for its specular reflection. The wide-angle scattering is similar to MV from A.

The soot shows no specular reflection peak but a more or less equally distributed scattering also at wide incident angles. The wide-angle scattering is 1.5-2 times the one from MV.
(for more details, just ask me)