Force printing in monochrome.
[read/write property] printForceMono([out, retval] VARIANT_BOOL *mono) printForceMono([in] VARIANT_BOOL mono)
If this property is set to true, XpdfViewer will generate monochrome output, even if the printer appears to be color.

This setting is only relevant for GDI printing, i.e., for non-PostScript printers, or if printForceGDI is true. It is ignored when XpdfViewer generates PostScript code.

viewer.printForceMono = True