ΔE 10.1, fair: the same colour family, but not a straight swap. Lucius Lilac is a little lighter, more muted, cooler than Matt Violet. They are different kinds of paint: AMMO by Mig Matt Violet is an ink, glaze or transparent paint and Citadel Lucius Lilac is an opaque base/layer 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 10). Lucius Lilac is a little lighter, more muted, cooler than Matt Violet. They are different kinds of paint.
The same difference applies the other way round: Matt Violet is a little darker, more saturated, warmer.
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 Matt Violet on the colour wheel See Lucius Lilac on the colour wheel
All matches: Matt Violet equivalents · Lucius Lilac equivalents