Dark Wood vs Endurance Brown

How close are they?

ΔE 17.1, loose: different enough that you should pick on purpose. Endurance Brown is noticeably lighter, more saturated, cooler than Dark Wood.

Can I use Endurance Brown instead of Dark Wood?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Endurance Brown is noticeably lighter, more saturated, cooler than Dark Wood.

Can I use Dark Wood instead of Endurance Brown?

The same difference applies the other way round: Dark Wood is noticeably 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.