ΔE 10.8, fair: the same colour family, but not a straight swap. Inktense Violet is noticeably darker than Eidolon Purple Clear. They are different kinds of paint: Citadel Eidolon Purple Clear is an opaque base/layer paint and Scale75 Inktense Violet 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). Inktense Violet is noticeably darker than Eidolon Purple Clear. They are different kinds of paint.
The same difference applies the other way round: Eidolon Purple Clear is noticeably lighter.
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 Eidolon Purple Clear on the colour wheel See Inktense Violet on the colour wheel
All matches: Eidolon Purple Clear equivalents · Inktense Violet equivalents