Simple white rectangular tiles with a faint grey marble effect (static meshes). When placed as a floor (with 8 units empty on each side) they look pretty grey. However, the same tiles are the ceiling and they look white. I have lights 64 units from floor but 212 from ceiling! There are no other lights, no 2 sided textures. I can't figure it out, when on the floor these white tiles look grey even when hovering around. Place them as a ceiling and they look white? Any ideas why illumination seems directional?