ΔE 19.8, loose: different enough that you should pick on purpose. Smoke Ink is a little lighter, more muted than Night Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Smoke Ink is a little lighter, more muted than Night Blue.
The same difference applies the other way round: Night Blue is a little darker, 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 Night Blue on the colour wheel See Smoke Ink on the colour wheel
All matches: Night Blue equivalents · Smoke Ink equivalents