[sdiy] My PCB positives are see through!

[Jeff Farr]

"If you mean that large areas of black are dense around the
edges, and light at the centre, you need a new print company.
On the bright side, any problems inside large areas, can be
touched up with opaque ink beforehand, if need be."

This is the situation.  Slightly annoyed about it too.  Using a
sharpie is a big PITA too, which leads me to Paul's comment. 
Unfortunately for some projects I have using 4pcb just isn't an option
as I can only get the layouts in .pdf, for the stuff I'm working on
from scratch tho, I'm certainly not going to bother doing the boards
myself!