Beaten Purple vs Dark Blue

How close are they?

ΔE 24.4, loose: different enough that you should pick on purpose. Dark Blue is much more muted, cooler than Beaten Purple.

Can I use Dark Blue instead of Beaten Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Dark Blue is much more muted, cooler than Beaten Purple.

Can I use Beaten Purple instead of Dark Blue?

The same difference applies the other way round: Beaten Purple is much 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.