ΔE 41.5, loose: different enough that you should pick on purpose. Ink Blue is noticeably darker, much more saturated, warmer than Sapphire Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 41). Ink Blue is noticeably darker, much more saturated, warmer than Sapphire Blue.
The same difference applies the other way round: Sapphire Blue is noticeably lighter, much more muted, 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.
See Sapphire Blue on the colour wheel See Ink Blue on the colour wheel
All matches: Sapphire Blue equivalents · Ink Blue equivalents