ΔE 9.0, close: similar, with a visible difference side by side. Dark Green is a little lighter, more muted, warmer than Lupercal Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Dark Green is a little lighter, more muted, warmer than Lupercal Green.
The same difference applies the other way round: Lupercal Green is a little darker, more saturated, cooler.
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 Lupercal Green on the colour wheel See Dark Green on the colour wheel
All matches: Lupercal Green equivalents · Dark Green equivalents