Green vs Eternal Hunt

How close are they?

ΔE 8.6, close: similar, with a visible difference side by side. Eternal Hunt is a little lighter, more saturated than Green.

Can I use Eternal Hunt instead of Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Eternal Hunt is a little lighter, more saturated than Green.

Can I use Green instead of Eternal Hunt?

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