Mecha Dark Green vs Lupercal Green

How close are they?

ΔE 6.9, close: similar, with a visible difference side by side. Lupercal Green is a little lighter, warmer than Mecha Dark Green.

Can I use Lupercal Green instead of Mecha Dark Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Lupercal Green is a little lighter, warmer than Mecha Dark Green.

Can I use Mecha Dark Green instead of Lupercal Green?

The same difference applies the other way round: Mecha Dark Green is a little darker, 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.