Aeldari Emerald vs Green Ghost

How close are they?

ΔE 22.8, loose: different enough that you should pick on purpose. Green Ghost is noticeably darker, more muted, warmer than Aeldari Emerald.

Can I use Green Ghost instead of Aeldari Emerald?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Green Ghost is noticeably darker, more muted, warmer than Aeldari Emerald.

Can I use Aeldari Emerald instead of Green Ghost?

The same difference applies the other way round: Aeldari Emerald is noticeably lighter, 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.