When I plot to our HP Designjet 500 Plus plotter the colors that are Red or Green on the display plot Yellow. We are using the Bentley HPGL2.PLTCFG Printer Driver Configuration file. We are not using a pen table and we are not using any pen mappings. BTW, this used to work.
Issue caused by a configuration setting at the plotter
At the front panel of the plotter set the Pen settings->Palette to Software instead of Factory or Palette A/B