Broodmother Purple vs Dark Grey Blue

How close are they?

ΔE 15.7, loose: different enough that you should pick on purpose. Dark Grey Blue is a little lighter, more muted, cooler than Broodmother Purple.

Can I use Dark Grey Blue instead of Broodmother Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Dark Grey Blue is a little lighter, more muted, cooler than Broodmother Purple.

Can I use Broodmother Purple instead of Dark Grey Blue?

The same difference applies the other way round: Broodmother Purple is a little darker, 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.