I had this problem about 5 years ago but can't remember how I fixed it. I received a layout of a building from a architect. When I try to print it out it is extreemly light. This happens no mater what printer or ploter I use. I have changed line weight with no success.
It seems to always happen when I get a building drawing from an arhitect.
Even the new items I have drawn like conveyors , tables stc. come out nearly invisable.
Sincerely Warren