ΔE 14.4, fair: the same colour family, but not a straight swap. Oxide Brown Dark is a little darker, more muted, warmer than Grimoire Purple.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Oxide Brown Dark is a little darker, more muted, warmer than Grimoire Purple.
The same difference applies the other way round: Grimoire Purple is a little lighter, more saturated, 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 Grimoire Purple on the colour wheel See Oxide Brown Dark on the colour wheel
All matches: Grimoire Purple equivalents · Oxide Brown Dark equivalents