Created attachment 433220 [details] emerge --info for qpdfview I seem to be hit by this upstream Bug https://bugs.launchpad.net/qpdfview/+bug/1331646. qpdfview doesn't honour its printing dialog option "Color Mode": whatever that's set to, the results only depend on contents of "~/.cups/lpoptions" or "/etc/cups/lpoptions". If no "Ink=" option is specified by lpoptions, then qpdfview always prints in color mode; conversely, if "Ink=MONO", it always prints in monochrome mode.
Forgot to say. GTK-based apps do not suffer from this bug.
Well, even upstream doesn't seem to have a solution for this, so I'm not sure what you want us to do... I'm closing as UPSTREAM for now. Please reopen when (if) a patch becomes available.