Thank you Westcork and Kovid,
This is very useful. Sometimes I need to convert articles in epub format to PDF for sharing and printing with colleagues who do mainly paper based reading. This summary is of great help.
There is another good link, but for my needs Westcork's summary is perfect.
https://maxrohde.com/2015/01/28/rend...-with-calibre/
Cheers,
Rob