Nightmare Purple vs Royal Purple

How close are they?

ΔE 14.4, fair: the same colour family, but not a straight swap. Royal Purple is much more muted, warmer than Nightmare Purple.

Can I use Royal Purple instead of Nightmare Purple?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Royal Purple is much more muted, warmer than Nightmare Purple.

Can I use Nightmare Purple instead of Royal Purple?

The same difference applies the other way round: Nightmare Purple is much more saturated, cooler.

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.