ΔE 6.1, close: similar, with a visible difference side by side. IJA Light Grey Green is cooler than Underhive Ash.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). IJA Light Grey Green is cooler than Underhive Ash.
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.
See Underhive Ash on the colour wheel See IJA Light Grey Green on the colour wheel
All matches: Underhive Ash equivalents · IJA Light Grey Green equivalents