Is there a white texture wich don't bright ?
I was wondering is there is some white textures that dosen't give any more light ?
It seems I can't find any
Of course, game-wise, you could just scale the white wall texture to be very large so the light doesn't show...
Also, may I suggest you use some realistic light sources in your map? It really helps in making your map look good if you do. Use some glass lights in the wall (with white texures mostly) or my personal favorite: observation labs! 
FourthReaper wrote:
Also, may I suggest you use some realistic light sources in your map? It really helps in making your map look good if you do. Use some glass lights in the wall (with white texures mostly) or my personal favorite: observation labs!
The levels I make for Portal 2 are Portal 1 style. The goal is for the player to feel like "wait, did I run portal 1 or Portal 2". The true feel is for the player to feel like on Portal 1 test chambers style and most of my light sources are from "light holes" wich were really typical from portal 1.
I also use observations rooms, and my white textured blocks are the "covers" of these glasses (I understand myself). The problem is, even with a very dark ambiance, al textures are very dark, we see almost nothing, and the white covers are still...like...almost shinning front of your eyes due that they are "overlighted".
I don't really understand how to make it dark or...maybe you can suggest some else texture for these observations room classes covers ?
The second post is about how light reflects off of walls, which is not the same issue.