ΔE 14.5, fair: the same colour family, but not a straight swap. Royal Blue is noticeably lighter, cooler than Kantor Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Royal Blue is noticeably lighter, cooler than Kantor Blue.
The same difference applies the other way round: Kantor Blue is noticeably darker, 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 Kantor Blue on the colour wheel See Royal Blue on the colour wheel
All matches: Kantor Blue equivalents · Royal Blue equivalents