Umberroot vs Sanguine Base

How close are they?

ΔE 16.0, loose: different enough that you should pick on purpose. Sanguine Base is a little darker, much more saturated than Umberroot.

Can I use Sanguine Base instead of Umberroot?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Sanguine Base is a little darker, much more saturated than Umberroot.

Can I use Umberroot instead of Sanguine Base?

The same difference applies the other way round: Umberroot is a little lighter, much more muted.

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.