Sooty Black INK vs Ink White

How close are they?

ΔE 64.4, loose: different enough that you should pick on purpose. Ink White is noticeably lighter, more muted than Sooty Black INK.

Can I use Ink White instead of Sooty Black INK?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 64). Ink White is noticeably lighter, more muted than Sooty Black INK.

Can I use Sooty Black INK instead of Ink White?

The same difference applies the other way round: Sooty Black INK is noticeably 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.