Coal Black vs Black Green

How close are they?

ΔE 16.2, loose: different enough that you should pick on purpose. Black Green is a little darker, much more muted than Coal Black.

Can I use Black Green instead of Coal Black?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Black Green is a little darker, much more muted than Coal Black.

Can I use Coal Black instead of Black Green?

The same difference applies the other way round: Coal Black is a little lighter, much 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.