ΔE 12.7, fair: the same colour family, but not a straight swap. Ink Black Green is more saturated than Inktense Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Ink Black Green is more saturated than Inktense Brown.
The same difference applies the other way round: Inktense Brown is more muted.
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 Inktense Brown on the colour wheel See Ink Black Green on the colour wheel
All matches: Inktense Brown equivalents · Ink Black Green equivalents