Comment 25 for bug 189720

I find that
  $ echo Xft.rgba: none | xrdb -merge
is needed to cause proper display, as configured in xfce-mcs-manager and also in fontconfig-config. Something's not making use of the settings or is trying to second-guess them (LCD monitor, but I can tell when RGB alleged subpixel a-a is in use - colour fringes are visible).

(Debian testing/unstable; Minefield 3 beta 3 compiled from source. I've not yet tried cairo from experimental.)