In my case 'gksu-cups-add' detected two ppds for ach driver tested (the gzipped and the gunzipped). e.g.:
** (gnome-cups-add:6359): WARNING **: Two ppds have driver == 'Standard' ->linuxprinting.org-postscript/Savin/Savin-SLP26n_PS.ppd.gz (Savin SLP26n PS[0]) and ->linuxprinting.org-gs-builtin/Savin/Savin-SLP26n-Postscript.ppd (Savin SLP26n PS)[0] ** (gnome-cups-add:6359): WARNING **: Two ppds have driver == 'Standard' ->linuxprinting.org-postscript/Savin/Savin-SLP32_PS.ppd.gz (Savin SLP32 PS[0]) and ->linuxprinting.org-gs-builtin/Savin/Savin-SLP32-Postscript.ppd (Savin SLP32 PS)[0] ** (gnome-cups-add:6359): WARNING **: Two ppds have driver == 'Standard' ->linuxprinting.org-postscript/Savin/Savin-SLP38c_PS.ppd.gz (Savin SLP38c PS[0]) and ->linuxprinting.org-gs-builtin/Savin/Savin-SLP38c-Postscript.ppd (Savin SLP38c PS)[0] ** (gnome-cups-add:6359): WARNING **: Two ppds have driver == '1.2' ->linuxprinting.org-postscript/Sharp/shc260mj.ppd.gz (Sharp AR-C260M PS, 1.2[0]) and ->linuxprinting.org-postscript/Sharp/shac260m.ppd.gz (Sharp AR-C260M PS, 1.2)[0] -- cupsys does not automatically detect parallel printer https://launchpad.net/bugs/29050 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs