ΔE 14.4, fair: the same colour family, but not a straight swap. Deep Green is much more muted, cooler than Dark Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Deep Green is much more muted, cooler than Dark Green.
The same difference applies the other way round: Dark Green is much more saturated, warmer.
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 Dark Green on the colour wheel See Deep Green on the colour wheel
All matches: Dark Green equivalents · Deep Green equivalents