print on both sides of paper

[Peter Flynn]

On 28/10/2022 23:58, Douglas McGArrett wrote:
> Folks:
> 
> System: Kubuntu 22.04
> 
> For some unknown reason, the developers don't want the user to print
> on both sides of paper, even if the file is a large one. It would
> seem that the printer definition file, which shows both of my
> printers as "print on one side" could fix that IF I could edit the
> file--but I can't. It seems to be protected by something other than
> sudo. (Or su -)  Questions: am I incorrect that the printer
> definition file controls this function, and if so, how do I edit the
> file? (If there is another answer to the 2-sided question, please
> point me to it. The internet answers seem utterly complicated.)

You are correct the the printer definition file controls whether or
not the print interface presents you with the option.

Assuming this is CUPS, the "driver" is a Postscript Printer Definition
(.ppd) file in /etc/cups/ppd named after your printer make and model.

I have a HP OfficeJet Pro 7720 so my PPD file is called
/etc/cups/ppd/HP_OfficeJet_Pro_7720_series_62189F_.ppd

In it, quite a long way down, there are some lines like this:

*OpenUI *Duplex/2-Sided Printing: PickOne
*OrderDependency: 10 AnySetup *Duplex
*DefaultDuplex: None
*Duplex None/Off: "<</Duplex false>>setpagedevice"
*Duplex DuplexNoTumble/On (Portrait): "<</Duplex true/Tumble 
false>>setpagedevice"
*Duplex DuplexTumble/On (Landscape): "<</Duplex true/Tumble 
true>>setpagedevice"
*CloseUI: *Duplex

The file is protected -rw-r----- 1 root  lp so you will need sudo to 
read it. I don't suggest you edit the file or make any changes but if 
you're not using CUPS, or if there is no such file, they you'll need to 
find out from your distribution support why it's not there.

Manufacturers often make changes to PPD files that break functionality. 
It's worth trying to download the latest one from the manufacturere's site.

Peter