Is there a way to change the font size or do other customization of the "Printable View" of a ticket?
It might be possible by modifying EmailStyleSheet.html. It would be quite complex though and this template is used in multiple places in the application but it just might work. Also any changes done in that file would be gone after upgrade. Lastly it is not really supported change by Solarwinds, so I'd be very careful.