Higher resolution printing in PPD

PPDs in /etc/cups/ppd/

*OpenUI *Resolution/Output Resolution: PickOne
*DefaultResolution: 600
*Resolution 600/600 dpi: "<</HWResolution[600 600]>>setpagedevice"
*Resolution 1200/1200 dpi: "<</HWResolution[1200 1200]>>setpagedevice"
*Resolution 2400/2400 dpi: "<</HWResolution[2400 2400]>>setpagedevice"
*CloseUI: *Resolution

Source