Praxeti White vs Ivory Tusk

How close are they?

ΔE 18.1, loose: different enough that you should pick on purpose. Ivory Tusk is noticeably darker, more saturated than Praxeti White.

Can I use Ivory Tusk instead of Praxeti White?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Ivory Tusk is noticeably darker, more saturated than Praxeti White.

Can I use Praxeti White instead of Ivory Tusk?

The same difference applies the other way round: Praxeti White 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.