Depending on the source of your sheet, different colors may be used to mark different properties of a sheet. In the Sphere XG Viewer, you can activate and deactivate black-and-white mode of a colored sheet, see figure below.
Select the sheet you want in the project structure view on the left side of the screen.
Click icon
in the toolbar on the right side of the screen.
This icon is also available in the screen where you can set the scale of the sheet or grid.
This feature has no effect on already black and white sheets.
Learn more about sheets and layers in the Sphere XG User Manual.