We have people using Journal and after writing equations in black ink they sometimes hi-lite with different colors. The yellow hi-liters "print" opaque when saving or printing to PDF files. ie, they cover the black writing below them. Whats up with that?

Joe

What application is that in, and what kind of printer (colour, black and white?)

My immediate though is to make sure that when you print you go into the print options and set it to best quality graphic mode and grayscale if it's a black and white printer. That should help a great deal.