Evil Root vs Dreadnought Yellow

How close are they?

ΔE 21.9, loose: different enough that you should pick on purpose. Dreadnought Yellow is a little darker, more saturated, warmer than Evil Root.

Can I use Dreadnought Yellow instead of Evil Root?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Dreadnought Yellow is a little darker, more saturated, warmer than Evil Root.

Can I use Evil Root instead of Dreadnought Yellow?

The same difference applies the other way round: Evil Root is a little lighter, more muted, cooler.

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.