To get accurate scaling plot to ps file from pcbnew (Kicad) and print with this command (printing from Okular caused scaling issues)

lp -d OKI -o OKMultiOutputMode=False -o media=A4,MultiPurpose -o OKManualFeed=true -o InputSlot=Front kilncontrol-B_Cu.ps

lp -d OKI -o OKMultiOutputMode=False -o OKOutputModeBlack=True -o media=A4,MultiPurpose -o OKManualFeed=true -o InputSlot=Front kilncontrol-B_Cu.ps