Coelia Greenshade vs Aether Blue

How close are they?

ΔE 45.6, loose: different enough that you should pick on purpose. Aether Blue is a little lighter, cooler than Coelia Greenshade.

Can I use Aether Blue instead of Coelia Greenshade?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 46). Aether Blue is a little lighter, cooler than Coelia Greenshade.

Can I use Coelia Greenshade instead of Aether Blue?

The same difference applies the other way round: Coelia Greenshade is a little darker, warmer.

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.