Underhive Ash vs Soft Green

How close are they?

ΔE 16.1, loose: different enough that you should pick on purpose. Soft Green is more saturated, cooler than Underhive Ash.

Can I use Soft Green instead of Underhive Ash?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Soft Green is more saturated, cooler than Underhive Ash.

Can I use Underhive Ash instead of Soft Green?

The same difference applies the other way round: Underhive Ash is more muted, 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.