ΔE 9.9, close: similar, with a visible difference side by side. Blue Black is a little lighter than Corvus Black.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Blue Black is a little lighter than Corvus Black.
The same difference applies the other way round: Corvus Black is a little darker.
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 Corvus Black on the colour wheel See Blue Black on the colour wheel
All matches: Corvus Black equivalents · Blue Black equivalents