Underhive Ash vs Pastel Green

How close are they?

ΔE 8.2, close: similar, with a visible difference side by side. Pastel Green is cooler than Underhive Ash.

Can I use Pastel Green instead of Underhive Ash?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Pastel Green is cooler than Underhive Ash.

Can I use Underhive Ash instead of Pastel Green?

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