Problem

When creating a pdf with pdf.pltcfg the fonts in the pdf look pixilated and not rendering correctly when zooming into the pdf. 

Solution

Make sure that you have set in the pdf.pltcfg driver the precision to high or maximum.

How to do this:

MicroStation -> File -> Print-> the Print Dialog box opens -> File -> Select Bentley Driver -> select the Bentley driver > pdf.pltcfg -> open -> the print dialog box is open
Print dialog box -> file -> Edit Printer Driver Configuration ->

Base Properties TAB -> Driver Properties -> Precision = Maximum

Advanced Properties TAB > Driver Resolution Units = Millimeters

File -> save; File -> exit.

The Print Dialog box is now open. Go to File -> Reload printer Driver Configuration.