Dark Prussian Blue vs Royal Purple

How close are they?

ΔE 14.5, fair: the same colour family, but not a straight swap. Royal Purple is much more saturated than Dark Prussian Blue.

Can I use Royal Purple instead of Dark Prussian Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Royal Purple is much more saturated than Dark Prussian Blue.

Can I use Dark Prussian Blue instead of Royal Purple?

The same difference applies the other way round: Dark Prussian Blue is much more muted.

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.