ΔE 15.3, loose: different enough that you should pick on purpose. Imperial Blue is a little lighter, much more muted than Mica Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Imperial Blue is a little lighter, much more muted than Mica Blue.
The same difference applies the other way round: Mica Blue is a little darker, much more saturated.
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 Mica Blue on the colour wheel See Imperial Blue on the colour wheel
All matches: Mica Blue equivalents · Imperial Blue equivalents