Ivory Tusk vs White

How close are they?

ΔE 16.9, loose: different enough that you should pick on purpose. White is a little lighter, much more muted than Ivory Tusk.

Can I use White instead of Ivory Tusk?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). White is a little lighter, much more muted than Ivory Tusk.

Can I use Ivory Tusk instead of White?

The same difference applies the other way round: Ivory Tusk is a little darker, much 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.