Loss of resolution when exporting to pdf

Since installing DraftSight V1R4.0 I have been getting problems with exporting to pdf.

 

Any hatched area, with a solid fill type hatch ends up really badly pixelated when exported to pdf.

 

I've never had this problem with previous versions and wonder if anyone else has had this happen?

 

I'm currently having to send the .dwg files to another computer with an older version installed and export to pdf from there

 

Any help much appreciated.