ΔE 9.6, close: similar, with a visible difference side by side. 3B Russian Green is a little lighter, more muted than Black Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). 3B Russian Green is a little lighter, more muted than Black Green.
The same difference applies the other way round: Black Green 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 Black Green on the colour wheel See 3B Russian Green on the colour wheel
All matches: Black Green equivalents · 3B Russian Green equivalents