ΔE 12.1, fair: the same colour family, but not a straight swap. Quinacridone Magenta is a little lighter, more muted than Witchbane Plum. They are different kinds of paint: Army Painter Witchbane Plum is an opaque base/layer paint and Golden Quinacridone Magenta is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Quinacridone Magenta is a little lighter, more muted than Witchbane Plum. They are different kinds of paint.
The same difference applies the other way round: Witchbane Plum is a little darker, more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Witchbane Plum on the colour wheel See Quinacridone Magenta on the colour wheel
All matches: Witchbane Plum equivalents · Quinacridone Magenta equivalents