ΔE 16.4, loose: different enough that you should pick on purpose. Royal Blue is much more muted, cooler than Character Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Royal Blue is much more muted, cooler than Character Blue.
The same difference applies the other way round: Character Blue 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.
See Character Blue on the colour wheel See Royal Blue on the colour wheel
All matches: Character Blue equivalents · Royal Blue equivalents