ΔE 8.1, close: similar, with a visible difference side by side. Extra Dark Seagray BS381C/640 is a little lighter, more muted than Incubi Darkness.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Extra Dark Seagray BS381C/640 is a little lighter, more muted than Incubi Darkness.
The same difference applies the other way round: Incubi Darkness is a little darker, more saturated.
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 Incubi Darkness on the colour wheel See Extra Dark Seagray BS381C/640 on the colour wheel
All matches: Incubi Darkness equivalents · Extra Dark Seagray BS381C/640 equivalents