Royal Blue vs Purple Rain

How close are they?

ΔE 13.5, fair: the same colour family, but not a straight swap. Purple Rain is a little lighter, warmer than Royal Blue.

Can I use Purple Rain instead of Royal Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Purple Rain is a little lighter, warmer than Royal Blue.

Can I use Royal Blue instead of Purple Rain?

The same difference applies the other way round: Royal Blue is a little darker, 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.