Xereus Purple vs Anthraquinone Blue

How close are they?

ΔE 20.5, loose: different enough that you should pick on purpose. Anthraquinone Blue is a little darker, more saturated, cooler than Xereus Purple.

Can I use Anthraquinone Blue instead of Xereus Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Anthraquinone Blue is a little darker, more saturated, cooler than Xereus Purple.

Can I use Xereus Purple instead of Anthraquinone Blue?

The same difference applies the other way round: Xereus Purple is a little lighter, 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.