Light Shelves Simulation

[Hummingbird]

I am trying to simulate the effect of internal light shelves.

The light shelf has a reflectance of 0,96 and specularity of 0,98 according to the official specs of the product. The surface of the shelf is pressed aluminum foil ASTM B211 with a roughness of 0.0013mm

The problem is that although the ceiling has a reflectance of 0,90, the light shelf does not make any difference unless I increase the specularity and roughness of the ceiling really alot. How much specularity and roughness can a plastered celeing have?

I found some values concerning the roughness in the following link
http://neutrium.net/fluid_flow/absolute-roughness/.

The roughness in the tab should be in mm, I guess.


Thank you in advance.


Thank you in advance