@tray_brown That's not how you print B/W or monochrome in any variant of AutoCAD including this free viewer.
The DWG file creators need to provide you with their PLOT STYLE TABLE predefined in the DWGs as a default first. The viewer offers no such ability to add/create.
Another option: find a 3rd party PDF driver that installs in Windows as a printer driver that includes a "monochrome' setting, you'll find that to be the most robust solution of all. I use this one for example
