Umberroot vs Feral Brown

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Feral Brown is noticeably darker, more muted, cooler than Umberroot.

Can I use Feral Brown instead of Umberroot?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Feral Brown is noticeably darker, more muted, cooler than Umberroot.

Can I use Umberroot instead of Feral Brown?

The same difference applies the other way round: Umberroot is noticeably lighter, more saturated, 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.