ΔE 10.6, fair: the same colour family, but not a straight swap. Purple Ink is warmer than Broodmother Purple. They are different kinds of paint: Army Painter Broodmother Purple is an opaque base/layer paint and Reaper Purple Ink 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 11). Purple Ink is warmer than Broodmother Purple. They are different kinds of paint.
The same difference applies the other way round: Broodmother Purple is cooler.
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 Broodmother Purple on the colour wheel See Purple Ink on the colour wheel
All matches: Broodmother Purple equivalents · Purple Ink equivalents