when multitexture everything gets much darker

hi…my problem relates using MultiTexturing; i use two units (on Voodoo2 can’t any more) to texture 2 images and don’t know why everything gets much more dark, so that i can hardly see if there’s anything on the screen - but generally it works…it seems like enabling multitexturing changes some brightness or…?
thx 4 help

Have a look at this thread