Aeldari Emerald vs Hulky Green

How close are they?

ΔE 28.9, loose: different enough that you should pick on purpose. Hulky Green is noticeably darker, much more muted than Aeldari Emerald.

Can I use Hulky Green instead of Aeldari Emerald?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Hulky Green is noticeably darker, much more muted than Aeldari Emerald.

Can I use Aeldari Emerald instead of Hulky Green?

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

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.