When rendering white: Don't.
Render light grey instead. Then you have some room to let the white have some highlights in the iimage without washing out.
Like when you guest host on Leno they give you a grey shirt and it looks white during your monologue on the screen.
Bes sure to use a combination of slightly yellow and slightly blue light color to give the light surfaces some dynamic effects to work with.
Dwight Atkinson