Irrlicht Engine

hi
i have a little problem.
when i initialize my device lke this:
device=createDevice(EDT_DIRECTX8,dimension2d<s32>(resolutionX,resolutionY),16,true,true,true,&receiver);
i get darker colors than normal but the textures become smooth.

and when i do this:
device=createDevice(EDT_DIRECTX8,dimension2d<s32>(resolutionX,resolutionY),32,true,true,true,&receiver);
i get bright colors but the textures are badly mapped

so i was wondering how do i get smoothly mapped textures and bright colors?? why does the 16 bit make it dark?

note: i use MaterialType=EMT_REFLECTION_2_LAYER

thanks