Underhive Ash vs Gray FS16440

How close are they?

ΔE 12.2, fair: the same colour family, but not a straight swap. Gray FS16440 is a little lighter, more saturated, cooler than Underhive Ash.

Can I use Gray FS16440 instead of Underhive Ash?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Gray FS16440 is a little lighter, more saturated, cooler than Underhive Ash.

Can I use Underhive Ash instead of Gray FS16440?

The same difference applies the other way round: Underhive Ash is a little darker, 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.