Matt Blood Red vs Ink Red

How close are they?

ΔE 19.5, loose: different enough that you should pick on purpose. Ink Red is noticeably darker, more saturated than Matt Blood Red.

Can I use Ink Red instead of Matt Blood Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Ink Red is noticeably darker, more saturated than Matt Blood Red.

Can I use Matt Blood Red instead of Ink Red?

The same difference applies the other way round: Matt Blood Red is noticeably lighter, more muted.

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.