Royal Purple vs Dark Metallic Blue

How close are they?

ΔE 32.6, loose: different enough that you should pick on purpose. Dark Metallic Blue is much more muted, cooler than Royal Purple.

Can I use Dark Metallic Blue instead of Royal Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 33). Dark Metallic Blue is much more muted, cooler than Royal Purple.

Can I use Royal Purple instead of Dark Metallic Blue?

The same difference applies the other way round: Royal 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.