On 05/20/14 14:05, Ed Greshko wrote:
On 05/20/14 12:57, Michael Hannon wrote:
and it *does* have the duplex printing option enabled:

    Double-sided printing: Long Edge (standard)

Sorry for the gratuitous trimming....  Just wanted to share my experience which probably doesn't fix your situation but may trigger others to think what may.....

I had much the opposite situation.  I have an HP 6500 with duplex capability.  It is configured in CUPS as "installed" and the default is set to " Double-Sided Printing: off".  Yet every time I printed I would get double-sided print-outs.  In checking the print options for each application I was using the Double-sided option was selected.  In order to get single-sided, I always had to manually revert it within all of the applications.

Ultimately, I ran "hp-toolbox"  (which isn't applicable to you) and set the default there....  After that, each application did pick up the default single sided.  So, it seems, settings are held in multiple places and I'm not certain where all the places are and which location has priority.....

Anyway.....  Just wondering, when you print from an application, if you checked to see what printer options are being used.

FWIW, this got to me thinking and I found where the per-user options are set.....

~/.cups/lpoptions

Duplex=DuplexNoTumble is set for a printer where the default should be
Double-sided printing: Long Edge


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Do not condemn the judgment of another because it differs from your own. You may both be wrong. -- Dandemis