Dark Blue vs Regal Blue

How close are they?

ΔE 10.2, fair: the same colour family, but not a straight swap. Regal Blue is more muted, cooler than Dark Blue.

Can I use Regal Blue instead of Dark Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Regal Blue is more muted, cooler than Dark Blue.

Can I use Dark Blue instead of Regal Blue?

The same difference applies the other way round: Dark Blue is 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.