thanks guys,
unfortunately to reduce the rendering time I had to sacrifice the lighting (and  anti-aliasing too) so the light output is a little weak and "cold", then I guess that the gamma correction accentuates that issue too, anyway I must admit Carrara is great to manage files with "heavy" vegetation (by Xfrog): actually  exporting the file in 3ds without replicated objects, Vue 6 Xstream  took about 7 minutes to load, and it would certainly come out better, but with time rendering the Bible! I'd like  to bring the C atmosphere quite to  those of Vue. hope doing that