ΔE 7.6, close: similar, with a visible difference side by side. Black Grey is a little darker than Tenebrous Teal.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Black Grey is a little darker than Tenebrous Teal.
The same difference applies the other way round: Tenebrous Teal is a little 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 Tenebrous Teal on the colour wheel See Black Grey on the colour wheel
All matches: Tenebrous Teal equivalents · Black Grey equivalents