Thank you all.
I'll try to improve this picture... Here a render with non-black textures :
I don't know if it's better, I'm not sure of that (black is good for masking imperfections).
By the way, now I'll try to add some shadows and some colored influences from atmosphere on surfaces (maybe with snow land surfaces, that will be better for this test)(somewhere I saw a Volker's render of procedural land colored by clouds, it was very great, I'm looking for this topic, if someone seen it).
But, it will not easy... Since two days I had a lot of render problems, too many work for my old computer.
nb : My apologizes (again), I speak english like a drunk dog. :/
