ΔE 5.8, very close: most people won’t see a difference side by side. IJA Olive Green is more muted, cooler than Dark Green Brown.
Yes, for most jobs. Very close match (ΔE 6). IJA Olive Green is more muted, cooler than Dark Green Brown.
The same difference applies the other way round: Dark Green Brown is 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 Brown on the colour wheel See IJA Olive Green on the colour wheel
All matches: Dark Green Brown equivalents · IJA Olive Green equivalents