ΔE 11.4, fair: the same colour family, but not a straight swap. Gloomy Violet is more saturated, warmer than Indigo Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Gloomy Violet is more saturated, warmer than Indigo Blue.
The same difference applies the other way round: Indigo Blue is more muted, 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 Indigo Blue on the colour wheel See Gloomy Violet on the colour wheel
All matches: Indigo Blue equivalents · Gloomy Violet equivalents