Lexmark MS810n / MS810dn / MS810dtn
From the printer control panel, set the paper type in the Paper menu to match the paper loaded in the tray.
Is the paper type for the tray set to Transparency?
Go to step 2.
Set the paper type to Transparency.
Check if you are using a recommended type of transparency.
Resend the print job.
Is the print quality still poor?
Contact customer support.
The problem is solved.